The most complete and summarized list of minerals (elements) inside the human body that you will find in one place.

This includes all minerals that are found in the human body, whether they have a known function or not. This document is very extensive, please give your computer time to upload all of the information from canvas. The elements in your body are made inside of stars and some of them are made from exploding stars. The element gold, which is in your body, was made from the collision of two neutron stars. This is amazing.

First off, what is a mineral (compared to an element)?

(the terms are used interchangeably)

In the context of nutrition, a mineral is a chemical element required as an essential nutrient by organisms to perform functions necessary for life. However, the four major structural elements in the human body by weight (oxygen, hydrogen, carbon, and nitrogen), are usually not included in lists of major nutrient minerals (nitrogen is considered a "mineral" for plants, as it often is included in fertilizers). These four elements compose about 96% of the weight of the human body, and major minerals (macrominerals) and minor minerals (also called trace elements) compose the remainder. Nutrient minerals, being elements, cannot be synthesized biochemically by living organisms. Plants get minerals from soil. Most of the minerals in a human diet come from eating plants and animals or from drinking water. As a group, minerals are one of the four groups of essential nutrients, the others of which are vitamins, essential fatty acids, and essential amino acids. The five major minerals in the human body are calcium, phosphorus, potassium, sodium, and magnesium. Some resources say there are more than 5 major minerals. This document lists 11 major minerals. All of the remaining elements in a human body are called "trace elements". The trace elements that have a specific biochemical function in the human body are sulfur, iron, chlorine, cobalt, copper, zinc, manganese, molybdenum, iodine, and selenium. Most chemical elements that are ingested by organisms are in the form of simple compounds. Plants absorb dissolved elements in soils, which are subsequently ingested by the herbivores and omnivores that eat them, and the elements move up the food chain. Larger organisms may also consume soil (geophagia) or use mineral resources, such as salt licks, to obtain limited minerals unavailable through other dietary sources.

What are minerals? Where are the elements (minerals) made? Inside of stars? in ➡ (Here)

Keep in mind that minerals do not cure any disease, except a disease caused by a deficiency of that mineral. So, if you have osteomalacia, some calcium might help. As a general rule, you may take in extra minerals, more than a particular cell needs, but that cell will not take in more than it needs. It knows how to protect itself. However, if you take in massive amounts of any mineral, this can cause serious problems and overwhelm the cell and various organs, esp. the kidney and liver. The RDA for the major vitamins and minerals (some will surprise you) is located➡ Here Click on any Mineral Tab below to find out the latest information on that mineral or chemical compound. The approximate weight of that mineral in the average human body (155 lbs.) is listed beside that mineral (in lbs.) To watch the video associated with that mineral, click on the video. (disclaimer)I am not offering any advise on taking any of these supplements or not taking them. I am presenting the most current information available on all of these substances as of (December, 2020). Asterisk coding: (1) asterisk* indicates a major mineral (2) asterisks** indicates a trace mineral (3) asterisks*** indicates an electrolyte mineral (4) asterisks**** indicates a mineral with a possible function in the human body (5) asterisks***** indicates a mineral with no known function in the human body: Color coding: (11) major minerals* (15) trace minerals** (5) electrolyte minerals (also major minerals)*** (5) minerals with a possible function in humans**** (29) minerals with no known function in humans (yet, they are in you, why?) *****

The number of pounds listed by each mineral is based on a person that weights 155 lbs. This is how many pounds of this mineral or element are in your body. Click on the mineral you are interested in for a short video and information.

Periodic Table of Minerals used by the human body and biological processes
Oxygen* (94.6 lbs.)
Carbon* (35.2 lbs.)
Hydrogen* (15.4 lbs.)
Nitrogen*(3.96 lbs.)
Calcium*(2.2 lbs.) (electrolyte)***
Phosphorus* (1.716 lbs.) (electrolyte)***
Sulfur* (0.308lbs.)
Potassium*(0.308 lbs.) (electrolyte)***
Sodium* (0.22 lbs.) (electrolyte)***
Chlorine* (Chloride form) (0.209 lbs.)
Iron** (0.00924lbs.)
Magnesium*(0.0418 lbs.) (electrolyte)***
Fluorine (Fluoride form)**** (0.00572 lbs.)
Zinc** (0.00506 lbs.)
Silicon** (0.0022lbs.)
Gallium***** (.0000015lbs.)
Rubidium***** (0.001496lbs.)
Strontium**** (0.000704 lbs.)
Bromine**** (0.00572 lbs.)
Lead***** (0.000264 lbs.)
Copper** (0.0001584 lbs.)
Aluminum***** (0.000132 lbs.)
Cadmium***** (0.0001 lbs.)
Cerium***** (0.000088 lbs.)
Barium***** (0.0000484 lbs.)
Tin***** (0.000044 lbs.)
Iodine** (Iodide form) (0.000044 lbs.)
Titanium***** (0.000044 lbs.)
Boron** (0.000036 lbs.)
Selenium** (0.000033 lbs.)
Nickel** (0.000033 lbs.)
Chromium** (0.0000308 lbs.)
Maganese** (0.0000264 lbs.)
Arsenic** (0.000014 lbs.)
Lithium** (0.000014 lbs.)
Mercury***** (0.0000132 lbs.)
Cesium***** (0.0000132 lbs.)
Moylbdenum** (0.000011 lbs.)
Germanium***** (0.000011 lbs.)
Cobalt** (0.0000066 lbs.)
Antimony***** (0.0000044 lbs.)
Silver***** (0.0000044 lbs.)
Niobium***** (0.0000033 lbs.)
Zirconium***** (0.0000022 lbs.)
Lanthanum***** (0.00000176 lbs.)
Tellurium***** (0.00000154 lbs.)
Yttrium***** (0.00000132 lbs.)
Bismuth***** (0.0000011 lbs.)
Thallium***** (0.0000011 lbs.)
Indium***** (0.00000088 lbs.)
Gold****💲 (0.00000044 lbs.)
Scandium***** (0.00000044 lbs.)
Tantalum***** (0.00000044 lbs.)
Vanadium** (0.00000024 lbs.)
Thorium***** (0.00000022 lbs.)
Uranium***** (0.00000022 lbs.)
Samarium***** (0.00000011 lbs.)
Tungsten***** (0.00000004 lbs.)
Berylium***** (0.000000009 lbs.)
Lutetium**** (? very small amount)

Elements used and (possibly used) by the human body and roles in there biological processes in ➡ (Here)

Purpose of Minerals
Number	Element	Fraction of mass	Mass (kg)	Atomic percent	Essential in humans (some might say no)	Negative effects of excess
8	Oxygen	0.65	43	24	Yes (e.g. water, electron acceptor)	Reactive oxygen species	16
6	Carbon	0.18	16	12	Yes (organic compounds)		14
1	Hydrogen	0.10	7	62	Yes (e.g. water)		1
7	Nitrogen	0.03	1.8	1.1	Yes (e.g. DNA and amino acids)		15
20	Calcium	0.014	1.0	0.22	Yes (e.g. Calmodulin and Hydroxylapatite in bones)		2
15	Phosphorus	0.011	0.78	0.22	Yes (e.g. DNA and phosphorylation)	Hyperphosphatemia	15
19	Potassium	2.0×10⁻³	0.14	0.033	Yes (e.g. Na⁺/K⁺-ATPase)		1
16	Sulfur	2.5×10⁻³	0.14	0.038	Yes (e.g. Cysteine, Methionine, Biotin, Thiamine)		16
11	Sodium	1.5×10⁻³	0.10	0.037	Yes (e.g. Na⁺/K⁺-ATPase)		1
17	Chlorine	1.5×10⁻³	0.095	0.024	Yes (e.g. Cl-transporting ATPase)		17
12	Magnesium	500×10⁻⁶	0.019	0.0070	Yes^[ (e.g. binding to ATP and other nucleotides)		2
26	Iron*	60×10⁻⁶	0.0042	0.00067	Yes (e.g. Hemoglobin, Cytochromes)		8
9	Fluorine	37×10⁻⁶	0.0026	0.0012	Yes (AUS, NZ), No (US, EU), Maybe (WHO)	toxic in high amounts	17
30	Zinc	32×10⁻⁶	0.0023	0.00031	Yes (e.g. Zinc finger proteins)		12
14	Silicon	20×10⁻⁶	0.0010	0.0058	Possibly		14
31	Gallium	4.9×10⁻⁶	?	0.0007	No		13
37	Rubidium	4.6×10⁻⁶	0.00068	0.000033	No		1
38	Strontium	4.6×10⁻⁶	0.00032	0.000033	——		2
35	Bromine	2.9×10⁻⁶	0.00026	0.000030	——		17
82	Lead	1.7×10⁻⁶	0.00012	0.0000045	No	toxic	14
29	Copper	1×10⁻⁶	0.000072	0.0000104	Yes (e.g. copper proteins)	toxic in higher amounts	11
13	Aluminum	870×10⁻⁹	0.000060	0.000015	No		13
48	Cadmium	720×10⁻⁹	0.000050	0.0000045	No	toxic	12
58	Cerium	570×10⁻⁹	0.000040		No
56	Barium	310×10⁻⁹	0.000022	0.0000012	No	toxic in higher amounts	2
50	Tin	240×10⁻⁹	0.000020	6.0×10⁻⁷	No		14
53	Iodine	160×10⁻⁹	0.000020	7.5×10⁻⁷	Yes (e.g. thyroxine, triiodothyronine)		17
22	Titanium	130×10⁻⁹	0.000020		No		4
5	Boron	690×10⁻⁹	0.000018	0.0000030	Probably		13
34	Selenium	190×10⁻⁹	0.000015	4.5×10⁻⁸	Yes	toxic in higher amounts	16
28	Nickel	140×10⁻⁹	0.000015	0.0000015	Probably	toxic in higher amounts	10
24	Chromium	24×10⁻⁹	0.000014	8.9×10⁻⁸	Yes		6
25	Manganese	170×10⁻⁹	0.000012	0.0000015	Yes (e.g. Mn-SOD)		7
33	Arsenic	260×10⁻⁹	0.000007	8.9×10⁻⁸	No	toxic	15
3	Lithium	31×10⁻⁹	0.000007	0.0000015	Yes (intercorrelated with the functions of several enzymes, hormones and vitamins)	toxic in higher amounts	1
80	Mercury	190×10⁻⁹	0.000006	8.9×10⁻⁸	No	toxic	12
55	Cesium	21×10⁻⁹	0.000006	1.0×10⁻⁷	No		1
42	Molybdenum	130×10⁻⁹	0.000005	4.5×10⁻⁸	Yes (e.g. the molybdenum oxotransferases, Xanthine oxidase and Sulfite oxidase)		6
32	Germanium		5×10⁻⁶		No		14
27	Cobalt	21×10⁻⁹	0.000003	3.0×10⁻⁷	Yes (cobalamin, B₁₂)		9
51	Antimony	110×10⁻⁹	0.000002		No	toxic	15
47	Silver	10×10⁻⁹	0.000002		No		11
41	Niobium	1600×10⁻⁹	0.0000015		No		5
40	Zirconium	6×10⁻⁶	0.000001	3.0×10⁻⁷	No		4
57	Lanthanum	1370×10⁻⁹	8×10⁻⁷		No
52	Tellurium	120×10⁻⁹	7×10⁻⁷		No		16
39	Yttrium		6×10⁻⁷		No		3
83	Bismuth		5×10⁻⁷		No		15
81	Thallium		5×10⁻⁷		No	highly toxic	13
49	Indium		4×10⁻⁷		No		13
79	Gold	3×10⁻⁹	2×10⁻⁷	3.0×10⁻⁷	No	uncoated nanoparticles possibly genotoxic	11
21	Scandium		2×10⁻⁷		No		3
73	Tantalum		2×10⁻⁷		No		5
23	Vanadium	260×10⁻⁹	1.1×10⁻⁷	1.2×10⁻⁸	Possibly (suggested osteo-metabolism (bone) growth factor)		5
90	Thorium		1×10⁻⁷		No	toxic, radioactive
92	Uranium		1×10⁻⁷	3.0×10⁻⁹	No	toxic, radioactive
62	Samarium		5.0×10⁻⁸		No
74	Tungsten		2.0×10⁻⁸		No		6
4	Beryllium		3.6×10⁻⁸	4.5×10⁻⁸	No	toxic in higher amounts	2
88	Radium		3×10⁻¹⁴	1×10⁻¹⁷	No	toxic, radioactive	2
71	Lutetium				Possibly	toxic in higher amounts	4

Roles in biological processes

List of Minerals
Dietary element	RDA/AI Male/Female (US) [mg]	UL (US and EU) [mg]	Category	High nutrient density dietary sources	Term for deficiency	Term for excess
Potassium	4700	NE; NE	A systemic electrolyte and is essential in coregulating ATP with sodium	Sweet potato, tomato, potato, beans, lentils, dairy products, seafood, banana, prune, carrot, orange	hypokalemia	hyperkalemia
Chlorine	2300	3600; NE	Needed for production of hydrochloric acid in the stomach and in cellular pump functions	Table salt (sodium chloride) is the main dietary source.	hypochloremia	hyperchloremia
Sodium	1500	2300; NE	A systemic electrolyte and is essential in coregulating ATP with potassium	Table salt (sodium chloride, the main source), sea vegetables, milk, and spinach.	hyponatremia	hypernatremia
Calcium	1000	2500; 2500	Needed for muscle, heart and digestive system health, builds bone, supports synthesis and function of blood cells	Dairy products, eggs, canned fish with bones (salmon, sardines), green leafy vegetables, nuts, seeds, tofu, thyme, oregano, dill, cinnamon.	hypocalcaemia	hypercalcaemia
Phosphorus	700	4000; 4000	A component of bones (see apatite), cells, in energy processing, in DNA and ATP (as phosphate) and many other functions	Red meat, dairy foods, fish, poultry, bread, rice, oats. In biological contexts, usually seen as phosphate	hypophosphatemia	hyperphosphatemia
Magnesium	420/320	350; 250	Required for processing ATP and for bones	Spinach, legumes, nuts, seeds, whole grains, peanut butter, avocado	hypomagnesemia, magnesium deficiency	hypermagnesemia
Iron	8/18	45; NE	Required for many proteins and enzymes, notably hemoglobin to prevent anemia	Meat, seafood, nuts, beans, dark chocolate	iron deficiency	iron overload disorder
Zinc	11/8	40; 25	Required for several classes of enzymes such as matrix metalloproteinases, liver alcohol dehydrogenase, carbonic anhydrase and zinc finger proteins	Oysters*, red meat, poultry, nuts, whole grains, dairy products	zinc deficiency	zinc toxicity
Manganese	2.3/1.8	11; NE	Required co-factor for superoxide dismutase	Grains, legumes, seeds, nuts, leafy vegetables, tea, coffee	manganese deficiency	manganism
Copper	0.9	10; 5	Required co-factor for cytochrome c oxidase	Liver, seafood, oysters, nuts, seeds; some: whole grains, legumes	copper deficiency	copper toxicity
Iodine	0.150	1.1; 0.6	Required for the synthesis of thyroid hormones	Seaweed (kelp or kombu)*, grains, eggs, iodized salt	iodine deficiency / goiter	Hyperthyroidism
Chromium	0.035/0.25	NE; NE	Involved in glucose and lipid metabolism, although its mechanisms of action in the body and the amounts needed for optimal health are not well-defined	Broccoli, grape juice (especially red), meat, whole grain products	Chromium deficiency	Chromium toxicity
Molybdenum	0.045	2; 0.6	Required for the functioning of xanthine oxidase, aldehyde oxidase, and sulfite oxidase	Legumes, whole grains, nuts	molybdenum deficiency	molybdenum toxicity
Selenium	0.055	0.4; 0.3	Essential to activity of antioxidant enzymes like glutathione peroxidase	Brazil nuts, seafoods, organ meats, meats, grains, dairy products, eggs	selenium deficiency	selenosis
Cobalt	none	NE; NE		Required in the synthesis of vitamin B₁₂, but because bacteria are required to synthesize the vitamin, it is usually considered part of vitamin B₁₂ which comes from eating animals and animal-sourced foods (eggs...)		Cobalt poisoning

RDA = Recommended Dietary Allowance; AI= Adequate intake; UL = Tolerable upper intake level; Figures shown are for adults age 31-50, male or female neither pregnant nor lactating

One serving of seaweed exceeds the US UL of 1100 μg but not the 3000 μg UL set by Japan.

Dietary nutrition

Dietitians may recommend that minerals are best supplied by ingesting specific foods rich with the chemical element(s) of interest. The elements may be naturally present in the food (e.g., calcium in dairy milk) or added to the food (e.g., orange juice fortified with calcium; iodized salt fortified with iodine). Dietary supplements can be formulated to contain several different chemical elements (as compounds), a combination of vitamins and/or other chemical compounds, or a single element (as a compound or mixture of compounds), such as calcium (calcium carbonate, calcium citrate) or magnesium (magnesium oxide), or iron (ferrous sulfate, iron bis-glycinate).

The dietary focus on chemical elements derives from an interest in supporting the biochemical reactions of metabolism with the required elemental components. Appropriate intake levels of certain chemical elements have been demonstrated to be required to maintain optimal health. Diet can meet all the body's chemical element requirements, although supplements can be used when some recommendations are not adequately met by the diet. An example would be a diet low in dairy products, and hence not meeting the recommendation for calcium.

Safety

The gap between recommended daily intake and what are considered safe upper limits (ULs) can be small. For example, for calcium the U.S. Food and Drug Administration set the recommended intake for adults over 70 years at 1,200 mg/day and the UL at 2,000 mg/day. The European Union also sets recommended amounts and upper limits, which are not always in accord with the U.S. Likewise, Japan, which sets the UL for iodine at 3000 μg versus 1100 for the U.S. and 600 for the EU. In the table above, magnesium appears to be an anomaly as the recommended intake for adult men is 420 mg/day (women 350 mg/day) while the UL is lower than the recommended, at 350 mg. The reason is that the UL is specific to consuming more than 350 mg of magnesium all at once, in the form of a dietary supplement, as this may cause diarrhea. Magnesium-rich foods do not cause this problem.

Elements considered possibly essential for humans but not confirmed

Many ultratrace elements have been suggested as essential, but such claims have usually not been confirmed. Definitive evidence for efficacy comes from the characterization of a biomolecule containing the element with an identifiable and testable function. One problem with identifying efficacy is that some elements are innocuous at low concentrations and are pervasive (examples: silicon and nickel in solid and dust), so proof of efficacy is lacking because deficiencies are difficult to reproduce. Ultratrace elements of some minerals such as silicon and boron are known to have a role but the exact biochemical nature is unknown, and others such as arsenic are suspected to have a role in health, but with weaker evidence.^[6]

Table of Minerals
Element	Description	Excess
Bromine	Possibly important to basement membrane architecture and tissue development, as a needed catalyst to make collagen IV	bromism
Arsenic	Essential in rat, hamster, goat and chicken models, but no research has been done in humans.	arsenic poisoning
Nickel	Nickel is an essential component of several enzymes, including urease and hydrogenase. Although not required by humans, some are thought to be required by gut bacteria, such as urease required by some varieties of Bifidobacterium.In humans, nickel may be a cofactor or structural component of certain metalloenzymes involved in hydrolysis, redox reactions and gene expression. Nickel deficiency depressed growth in goats, pigs, and sheep, and diminished circulating thyroid hormone concentration in rats.	Nickel toxicity
Fluorine	Fluorine (as fluoride) is not considered an essential element because humans do not require it for growth or to sustain life. Research indicates that the primary dental benefit from fluoride occurs at the surface from topical exposure. Of the minerals in this table, fluoride is the only one for which the U.S. Institute of Medicine has established an Adequate Intake.	Fluoride poisoning
Boron	Boron is an essential plant nutrient, required primarily for maintaining the integrity of cell walls. Boron has been shown to be essential to complete the life cycle in representatives of all kingdoms of life. In animals, supplemental boron has been shown to reduce calcium excretion and activate vitamin D.	No acute effects (LD50 of boric acid is 2.5 grams per kilogram body weight) Chronic effects of long term high dose boron exposure are not fully elucidated
Lithium	It is not known whether lithium has a physiological role in any species, but nutritional studies in some mammals have indicated its importance to health, leading to a suggestion that it be classed as an essential trace element.	Lithium toxicity
Strontium	Strontium has been found to be involved in the utilization of calcium in the body. It has promoting action on calcium uptake into bone at moderate dietary strontium levels, but a rachitogenic (rickets-producing) action at higher dietary levels.	Certain forms of Rickets
Other	Silicon and vanadium have established, albeit specialized, biochemical roles as structural or functional cofactors in other organisms, and are possibly, even probably, used by mammals (including humans). By contrast, tungsten, the early lanthanides, and cadmium have specialized biochemical uses in certain lower organisms, but these elements appear not to be utilized by mammals.Other elements considered to be possibly essential include aluminium, germanium, lead, rubidium, and tin.	Multiple

What is Oxygen?

(in about 4 minutes)

Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as well as with other compounds. After hydrogen and helium, oxygen is the third-most abundant element in the universe by mass. At standard temperature and pressure, two atoms of the element bind to form dioxygen, a colorless and odorless diatomic gas with the formula O2. Diatomic oxygen gas constitutes 20.95% of the Earth's atmosphere. Oxygen makes up almost half of the Earth's crust in the form of oxides. Dioxygen provides the energy released in combustion[and aerobic cellular respiration, and many major classes of organic molecules in living organisms contain oxygen atoms, such as proteins, nucleic acids, carbohydrates, and fats, as do the major constituent inorganic compounds of animal shells, teeth, and bone. Most of the mass of living organisms is oxygen as a component of water, the major constituent of lifeforms. Oxygen is continuously replenished in Earth's atmosphere by photosynthesis, which uses the energy of sunlight to produce oxygen from water and carbon dioxide. Oxygen is too chemically reactive to remain a free element in air without being continuously replenished by the photosynthetic action of living organisms. Another form (allotrope) of oxygen, ozone (O3), strongly absorbs ultraviolet UVB radiation and the high-altitude ozone layer helps protect the biosphere from ultraviolet radiation. However, ozone present at the surface is a byproduct of smog and thus a pollutant.

Safety and precautions

The NFPA 704 standard rates compressed oxygen gas as nonhazardous to health, nonflammable and nonreactive, but an oxidizer. Refrigerated liquid oxygen (LOX) is given a health hazard rating of 3 (for increased risk of hyperoxia from condensed vapors, and for hazards common to cryogenic liquids such as frostbite), and all other ratings are the same as the compressed gas form.

Toxicity

Main symptoms of oxygen toxicity Oxygen gas (O2) can be toxic at elevated partial pressures, leading to convulsions and other health problems. Oxygen toxicity usually begins to occur at partial pressures more than 50 kilopascals (kPa), equal to about 50% oxygen composition at standard pressure or 2.5 times the normal sea-level O2 partial pressure of about 21 kPa. This is not a problem except for patients on mechanical ventilators, since gas supplied through oxygen masks in medical applications is typically composed of only 30%–50% O2 by volume (about 30 kPa at standard pressure). At one time, premature babies were placed in incubators containing O2-rich air, but this practice was discontinued after some babies were blinded by the oxygen content being too high. Breathing pure O2 in space applications, such as in some modern space suits, or in early spacecraft such as Apollo, causes no damage due to the low total pressures used. In the case of spacesuits, the O2 partial pressure in the breathing gas is, in general, about 30 kPa (1.4 times normal), and the resulting O2 partial pressure in the astronaut's arterial blood is only marginally more than normal sea-level O2 partial pressure. Oxygen toxicity to the lungs and central nervous system can also occur in deep scuba diving and surface supplied diving. Prolonged breathing of an air mixture with an O2 partial pressure more than 60 kPa can eventually lead to permanent pulmonary fibrosis. Exposure to an O2 partial pressures greater than 160 kPa (about 1.6 atm) may lead to convulsions (normally fatal for divers). Acute oxygen toxicity (causing seizures, its most feared effect for divers) can occur by breathing an air mixture with 21% O2 at 66 m (217 ft.) or more of depth; the same thing can occur by breathing 100% O2 at only 6 m (20 ft.)

What is Carbon

(in 8 minutes)

Carbon (from Latin: carbo "coal") is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon makes up only about 0.025 percent of Earth's crust. Three isotopes occur naturally, 12C and 13C being stable, while 14C is a radionuclide, decaying with a half-life of about 5,730 years. Carbon is one of the few elements known since antiquity. Carbon is the 15th most abundant element in the Earth's crust, and the fourth most abundant element in the universe by mass after hydrogen, helium, and oxygen. Carbon's abundance, its unique diversity of organic compounds, and its unusual ability to form polymers at the temperatures commonly encountered on Earth enables this element to serve as a common element of all known life. It is the second most abundant element in the human body by mass (about 18.5%) after oxygen. The atoms of carbon can bond together in diverse ways, resulting in various allotropes of carbon. The best known allotropes are graphite, diamond, and buckminsterfullerene. The physical properties of carbon vary widely with the allotropic form. For example, graphite is opaque and black while diamond is highly transparent. Graphite is soft enough to form a streak on paper (hence its name, from the Greek verb "γράφειν" which means "to write"), while diamond is the hardest naturally occurring material known. Graphite is a good electrical conductor while diamond has a low electrical conductivity. Under normal conditions, diamond, carbon nanotubes, and graphene have the highest thermal conductivities of all known materials. All carbon allotropes are solids under normal conditions, with graphite being the most thermodynamically stable form at standard temperature and pressure. They are chemically resistant and require high temperature to react even with oxygen.

What is Hydrogen?

(in less than 1 minute)

Hydrogen is the chemical element with the symbol H and atomic number 1. With a standard atomic weight of 1.008, hydrogen is the lightest element in the periodic table. Hydrogen is the most abundant chemical substance in the universe, constituting roughly 75% of all baryonic mass. Non-remnant stars are mainly composed of hydrogen in the plasma state. The most common isotope of hydrogen, termed protium (name rarely used, symbol H), has one proton and no neutrons.

The universal emergence of atomic hydrogen first occurred during the recombination epoch (Big Bang). At standard temperature and pressure, hydrogen is a colorless, odorless, tasteless, non-toxic, nonmetallic, highly combustible diatomic gas with the molecular formula H₂. Since hydrogen readily forms covalent compounds with most nonmetallic elements, most of the hydrogen on Earth exists in molecular forms such as water or organic compounds. Hydrogen plays a particularly important role in acid–base reactions because most acid-base reactions involve the exchange of protons between soluble molecules. In ionic compounds, hydrogen can take the form of a negative charge (i.e., anion) when it is known as a hydride, or as a positively charged (i.e., cation) species denoted by the symbol H+. The hydrogen cation is written as though composed of a bare proton, but in reality, hydrogen cations in ionic compounds are always more complex. As the only neutral atom for which the Schrödinger equation can be solved analytically, study of the energetics and bonding of the hydrogen atom has played a key role in the development of quantum mechanics.

Hydrogen gas was first artificially produced in the early 16th century by the reaction of acids on metals. In 1766–81, Henry Cavendish was the first to recognize that hydrogen gas was a discrete substance, and that it produces water when burned, the property for which it was later named: in Greek, hydrogen means "water-former".

What is Nitrogen?

(in less that 5 minutes)

Nitrogen is the chemical element with the symbol N and atomic number 7. It was first discovered and isolated by Scottish physician Daniel Rutherford in 1772. Although Carl Wilhelm Scheele and Henry Cavendish had independently done so at about the same time, Rutherford is generally accorded the credit because his work was published first. The name nitrogène was suggested by French chemist Jean-Antoine-Claude Chaptal in 1790 when it was found that nitrogen was present in nitric acid and nitrates. Antoine Lavoisier suggested instead the name azote, from the Greek ἀζωτικός "no life", as it is an asphyxiant gas; this name is instead used in many languages, such as French, Italian, Russian, Romanian and Turkish, and appears in the English names of some nitrogen compounds such as hydrazine, azides and azo compounds. Adenine is a purine base of nucleic acids. Its status as a human vitamin is doubtful.

Apart from its use in fertilizer's and energy-stores, nitrogen is a constituent of organic compounds as diverse as Kevlar used in high-strength fabric and cyanoacrylate used in superglue. Nitrogen is a constituent of every major pharmacological drug class, including antibiotics. Many drugs are mimics or prodrugs of natural nitrogen-containing signal molecules: for example, the organic nitrates nitroglycerin and nitroprusside control blood pressure by metabolizing into nitric oxide. Many notable nitrogen-containing drugs, such as the natural caffeine and morphine or the synthetic amphetamines, act on receptors of animal neurotransmitters.

What is Calcium

(in 1 minute)

Calcium and bone health

(in 2 minutes)

Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to its heavier homologues strontium and barium. It is the fifth most abundant element in Earth's crust and the third most abundant metal, after iron and aluminum. The most common calcium compound on Earth is calcium carbonate, found in limestone and the fossilized remnants of early sea life; gypsum, anhydrite, fluorite, and apatite are also sources of calcium. The name derives from Latin calx "lime", which was obtained from heating limestone.

Some calcium compounds were known to the ancients, though their chemistry was unknown until the seventeenth century. Pure calcium was isolated in 1808 via electrolysis of its oxide by Humphry Davy, who named the element. Calcium compounds are widely used in many industries: in foods and pharmaceuticals for calcium supplementation, in the paper industry as bleaches, as components in cement and electrical insulators, and in the manufacture of soaps. On the other hand, the metal in pure form has few applications due to its high reactivity; still, in small quantities it is often used as an alloying component in steelmaking, and sometimes, as a calcium–lead alloy, in making automotive batteries.

Calcium is the most abundant metal and the fifth-most abundant element in the human body. As electrolytes, calcium ions play a vital role in the physiological and biochemical processes of organisms and cells: in signal transduction pathways where they act as a second messenger; in neurotransmitter release from neurons; in contraction of all muscle cell types; as cofactors in many enzymes; and in fertilization. Calcium ions outside cells are important for maintaining the potential difference across excitable cell membranes, protein synthesis, and bone formation.

Food sources

Foods rich in calcium include dairy products, such as yogurt and cheese, sardines, salmon, soy products, kale, and fortified breakfast cereals. Because of concerns for long-term adverse side effects, including calcification of arteries and kidney stones, both the U.S. Institute of Medicine (IOM) and the European Food Safety Authority (EFSA) set Tolerable Upper Intake Levels (ULs) for combined dietary and supplemental calcium. From the IOM, people of ages 9–18 years are not to exceed 3 g/day combined intake; for ages 19–50, not to exceed 2.5 g/day; for ages 51 and older, not to exceed 2 g/day.[50] EFSA set the UL for all adults at 2.5 g/day, but decided the information for children and adolescents was not sufficient to determine ULs.

**RDA**
Age	Calcium (mg/day)
1–3 years	700
4–8 years	1000
9–18 years	1300
19–50 years	1000
>51 years	1000
Pregnancy	1000
Lactation	1000

Biological and pathological role

Calcium is an essential element needed in large quantities. The Ca2+ ion acts as an electrolyte and is vital to the health of the muscular, circulatory, and digestive systems; is indispensable to the building of bone; and supports synthesis and function of blood cells. For example, it regulates the contraction of muscles, nerve conduction, and the clotting of blood. As a result, intra- and extracellular calcium levels are tightly regulated by the body. Calcium can play this role because the Ca2+ ion forms stable coordination complexes with many organic compounds, especially proteins; it also forms compounds with a wide range of solubility, enabling the formation of the skeleton.

Binding

Calcium ions may be complexed by proteins through binding the carboxyl groups of glutamic acid or aspartic acid residues; through interacting with phosphorylated serine, tyrosine, or threonine residues; or by being chelated by γ-carboxylated amino acid residues. Trypsin, a digestive enzyme, uses the first method; osteocalcin, a bone matrix protein, uses the third. Some other bone matrix proteins such as osteopontin and bone sialoprotein use both the first and the second. Direct activation of enzymes by binding calcium is common; some other enzymes are activated by noncovalent association with direct calcium-binding enzymes. Calcium also binds to the phospholipid layer of the cell membrane, anchoring proteins associated with the cell surface.

Solubility

As an example of the wide range of solubility of calcium compounds, monocalcium phosphate is very soluble in water, 85% of extracellular calcium is as dicalcium phosphate with a solubility of 2.0 mM and the hydroxyapatite of bones in an organic matrix is tricalcium phosphate at 100 μM.

Nutrition

Calcium is a common constituent of multivitamin dietary supplements, but the composition of calcium complexes in supplements may affect its bioavailability which varies by solubility of the salt involved: calcium citrate, malate, and lactate are highly bioavailable, while the oxalate is less. Other calcium preparations include calcium carbonate, calcium citrate malate, and calcium gluconate. The intestine absorbs about one-third of calcium eaten as the free ion, and plasma calcium level is then regulated by the kidneys.

Hormonal regulation of bone formation and serum levels

Parathyroid hormone and vitamin D promote the formation of bone by allowing and enhancing the deposition of calcium ions there, allowing rapid bone turnover without affecting bone mass or mineral content. When plasma calcium levels fall, cell surface receptors are activated and the secretion of parathyroid hormone occurs; it then proceeds to stimulate the entry of calcium into the plasma pool by taking it from targeted kidney, gut, and bone cells, with the bone-forming action of parathyroid hormone being antagonized by calcitonin, whose secretion increases with increasing plasma calcium levels.

Abnormal serum levels

Excess intake of calcium may cause hypercalcemia. However, because calcium is absorbed rather inefficiently by the intestines, high serum calcium is more likely caused by excessive secretion of parathyroid hormone (PTH) or possibly by excessive intake of vitamin D, both which facilitate calcium absorption. All these conditions result in excess calcium salts being deposited in the heart, blood vessels, or kidneys. Symptoms include anorexia, nausea, vomiting, memory loss, confusion, muscle weakness, increased urination, dehydration, and metabolic bone disease. Chronic hypercalcaemia typically leads to calcification of soft tissue and its serious consequences: for example, calcification can cause loss of elasticity of vascular walls and disruption of laminar blood flow—and thence to plaque rupture and thrombosis. Conversely, inadequate calcium or vitamin D intakes may result in hypocalcemia, often caused also by inadequate secretion of parathyroid hormone or defective PTH receptors in cells. Symptoms include neuromuscular excitability, which potentially causes tetany and disruption of conductivity in cardiac tissue.

Bone disease and Kidney stones

As calcium is required for bone development, many bone diseases can be traced to the organic matrix or the hydroxyapatite in molecular structure or organization of bone. Osteoporosis is a reduction in mineral content of bone per unit volume, and can be treated by supplementation of calcium, vitamin D, and bisphosphonates. Inadequate amounts of calcium, vitamin D, or phosphates can lead to softening of bones, called osteomalacia.

What is Phosphorus?

(in 3 minutes)

Phosphorus is a chemical element with the symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus, but because it is highly reactive, phosphorus is never found as a free element on Earth. It has a concentration in the Earth's crust of about one gram per kilogram (compare copper at about 0.06 grams). In minerals, phosphorus generally occurs as phosphate. Elemental phosphorus was first isolated as white phosphorus in 1669. White phosphorus emits a faint glow when exposed to oxygen – hence the name, taken from Greek mythology, Φωσφόρος meaning "light-bearer" (Latin Lucifer), referring to the "Morning Star", the planet Venus. The term "phosphorescence", meaning glow after illumination, derives from this property of phosphorus, although the word has since been used for a different physical process that produces a glow. The glow of phosphorus is caused by oxidation of the white (but not red) phosphorus — a process now called chemiluminescence. Together with nitrogen, arsenic, antimony, and bismuth, phosphorus is classified as a pnictogen. Phosphorus is essential for life. Phosphates (compounds containing the phosphate ion, PO43−) are a component of DNA, RNA, ATP, and phospholipids. Elemental phosphorus was first isolated from human urine, and bone ash was an important early phosphate source. Phosphate mines contain fossils because phosphate is present in the fossilized deposits of animal remains and excreta. Low phosphate levels are an important limit to growth in some aquatic systems. The vast majority of phosphorus compounds mined are consumed as fertilizers. Phosphate is needed to replace the phosphorus that plants remove from the soil, and its annual demand is rising nearly twice as fast as the growth of the human population. Other applications include organophosphorus compounds in detergents, pesticides, and nerve agents.

Biological role

Inorganic phosphorus in the form of the phosphate PO3−4 is required for all known forms of life.[88] Phosphorus plays a major role in the structural framework of DNA and RNA. Living cells use phosphate to transport cellular energy with adenosine triphosphate (ATP), necessary for every cellular process that uses energy. ATP is also important for phosphorylation, a key regulatory event in cells. Phospholipids are the main structural components of all cellular membranes. Calcium phosphate salts assist in stiffening bones. Biochemists commonly use the abbreviation "Pi" to refer to inorganic phosphate.

Every living cell is encased in a membrane that separates it from its surroundings. Cellular membranes are composed of a phospholipid matrix and proteins, typically in the form of a bilayer. Phospholipids are derived from glycerol with two of the glycerol hydroxyl (OH) protons replaced by fatty acids as an ester, and the third hydroxyl proton has been replaced with phosphate bonded to another alcohol.

An average adult human contains about 0.7 kg of phosphorus, about 85–90% in bones and teeth in the form of apatite, and the remainder in soft tissues and extracellular fluids (~1%). The phosphorus content increases from about 0.5 weight% in infancy to 0.65–1.1 weight% in adults. Average phosphorus concentration in the blood is about 0.4 g/L, about 70% of that is organic and 30% inorganic phosphates. An adult with healthy diet consumes and excretes about 1–3 grams of phosphorus per day, with consumption in the form of inorganic phosphate and phosphorus-containing biomolecules such as nucleic acids and phospholipids; and excretion almost exclusively in the form of phosphate ions such as H2PO−4 and HPO2−4. Only about 0.1% of body phosphate circulates in the blood, paralleling the amount of phosphate available to soft tissue cells.

Bone and teeth enamel

The main component of bone is hydroxyapatite as well as amorphous forms of calcium phosphate, possibly including carbonate. Hydroxyapatite is the main component of tooth enamel. Water fluoridation enhances the resistance of teeth to decay by the partial conversion of this mineral to the still harder material called fluoroapatite

Phosphorus deficiency

In medicine, phosphate deficiency syndrome may be caused by malnutrition, by failure to absorb phosphate, and by metabolic syndromes that draw phosphate from the blood (such as in refeeding syndrome after malnutrition) or pass too much of it into the urine. All are characterized by hypophosphatemia, which is a condition of low levels of soluble phosphate levels in the blood serum and inside the cells. Symptoms of hypophosphatemia include neurological dysfunction and disruption of muscle and blood cells due to lack of ATP. Too much phosphate can lead to diarrhea and calcification (hardening) of organs and soft tissue, and can interfere with the body's ability to use iron, calcium, magnesium, and zinc. Phosphorus is an essential macromineral for plants, which is studied extensively in edaphology to understand plant uptake from soil systems. Phosphorus is a limiting factor in many ecosystems; that is, the scarcity of phosphorus limits the rate of organism growth. An excess of phosphorus can also be problematic, especially in aquatic systems where eutrophication sometimes leads to algae blooms.

Nutrition

The U.S. Institute of Medicine (IOM) updated Estimated Average Requirements (EARs) and Recommended Dietary Allowances (RDAs) for phosphorus in 1997. If there is not sufficient information to establish EARs and RDAs, an estimate designated Adequate Intake (AI) is used instead. The current EAR for phosphorus for people ages 19 and up is 580 mg/day. The RDA is 700 mg/day. RDAs are higher than EARs so as to identify amounts that will cover people with higher than average requirements. RDA for pregnancy and lactation are also 700 mg/day. For children ages 1–18 years the RDA increases with age from 460 to 1250 mg/day. As for safety, the IOM sets Tolerable upper intake levels (ULs) for vitamins and minerals when evidence is sufficient. In the case of phosphorus the UL is 4000 mg/day. Collectively the EARs, RDAs, AIs and ULs are referred to as Dietary Reference Intakes (DRIs). The European Food Safety Authority (EFSA) refers to the collective set of information as Dietary Reference Values, with Population Reference Intake (PRI) instead of RDA, and Average Requirement instead of EAR. AI and UL defined the same as in United States. For people ages 15 and older, including pregnancy and lactation, the AI is set at 550 mg/day. For children ages 4–10 years the AI is 440 mg/day, for ages 11–17 640 mg/day. These AIs are lower than the U.S RDAs. In both systems, teenagers need more than adults. The European Food Safety Authority reviewed the same safety question and decided that there was not sufficient information to set a UL.

For U.S. food and dietary supplement labeling purposes the amount in a serving is expressed as a percent of Daily Value (%DV). For phosphorus labeling purposes 100% of the Daily Value was 1000 mg, but as of May 27, 2016 it was revised to 1250 mg to bring it into agreement with the RDA. Compliance with the updated labeling regulations was required by 1 January 2020, for manufacturers with $10 million or more in annual food sales, and by 1 January 2021, for manufacturers with less than $10 million in annual food sales. During the first six months following the 1 January 2020 compliance date, the FDA plans to work cooperatively with manufacturers to meet the new Nutrition Facts label requirements and will not focus on enforcement actions regarding these requirements during that time. A table of the old and new adult Daily Values is provided at Reference Daily Intake.

Food sources

The main food sources for phosphorus are the same as those containing protein, although proteins do not contain phosphorus. For example, milk, meat, and soya typically also have phosphorus. As a rule, if a diet has sufficient protein and calcium, the amount of phosphorus is probably sufficient.

Precautions

Organic compounds of phosphorus form a wide class of materials; many are required for life, but some are extremely toxic. Fluorophosphate esters are among the most potent neurotoxins known. A wide range of organophosphorus compounds are used for their toxicity as pesticides (herbicides, insecticides, fungicides, etc.) and weaponized as nerve agents against enemy humans. Most inorganic phosphates are relatively nontoxic and essential nutrients.

The white phosphorus allotrope presents a significant hazard because it ignites in air and produces phosphoric acid residue. Chronic white phosphorus poisoning leads to necrosis of the jaw called "phossy jaw". White phosphorus is toxic, causing severe liver damage on ingestion and may cause a condition known as "Smoking Stool Syndrome".

In the past, external exposure to elemental phosphorus was treated by washing the affected area with 2% copper sulfate solution to form harmless compounds that are then washed away. According to the recent US Navy's Treatment of Chemical Agent Casualties and Conventional Military Chemical Injuries: FM8-285: Part 2 Conventional Military Chemical Injuries, "Cupric (copper(II)) sulfate has been used by U.S. personnel in the past and is still being used by some nations. However, copper sulfate is toxic and its use will be discontinued. Copper sulfate may produce kidney and cerebral toxicity as well as intravascular hemolysis."

The manual suggests instead "a bicarbonate solution to neutralize phosphoric acid, which will then allow removal of visible white phosphorus. Particles often can be located by their emission of smoke when air strikes them, or by their phosphorescence in the dark. In dark surroundings, fragments are seen as luminescent spots. Promptly debride the burn if the patient's condition will permit removal of bits of WP (white phosphorus) that might be absorbed later and possibly produce systemic poisoning. DO NOT apply oily-based ointments until it is certain that all WP has been removed. Following complete removal of the particles, treat the lesions as thermal burns." As white phosphorus readily mixes with oils, any oily substances or ointments are not recommended until the area is thoroughly cleaned and all white phosphorus removed.

People can be exposed to phosphorus in the workplace by inhalation, ingestion, skin contact, and eye contact. The Occupational Safety and Health Administration (OSHA) has set the phosphorus exposure limit (Permissible exposure limit) in the workplace at 0.1 mg/m3 over an 8-hour workday. The National Institute for Occupational Safety and Health (NIOSH) has set a Recommended exposure limit (REL) of 0.1 mg/m3 over an 8-hour workday. At levels of 5 mg/m3, phosphorus is immediately dangerous to life and health.

What is Sulfur?

(in less than 2 minutes)

What are the Health Benefits of Sulfur?

(in 3 minutes)

Sulfur (in British English: sulphur) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formula S8. Elemental sulfur is a bright yellow, crystalline solid at room temperature.

Sulfur is the tenth most common element by mass in the universe, and the fifth most common on Earth. Though sometimes found in pure, native form, sulfur on Earth usually occurs as sulfide and sulfate minerals. Being abundant in native form, sulfur was known in ancient times, being mentioned for its uses in ancient India, ancient Greece, China, and Egypt. Historically and in literature sulfur is also called brimstone, which means "burning stone". Today, almost all elemental sulfur is produced as a byproduct of removing sulfur-containing contaminants from natural gas and petroleum. The greatest commercial use of the element is the production of sulfuric acid for sulfate and phosphate fertilizers, and other chemical processes. The element sulfur is used in matches, insecticides, and fungicides. Many sulfur compounds are odoriferous, and the smells of odorized natural gas, skunk scent, grapefruit, and garlic are due to organosulfur compounds. Hydrogen sulfide gives the characteristic odor to rotting eggs and other biological processes.

Sulfur is an essential element for all life, but almost always in the form of organosulfur compounds or metal sulfides. Three amino acids (cysteine, cystine, and methionine) and two vitamins (biotin and thiamine) are organosulfur compounds. Many cofactors also contain sulfur, including glutathione, thioredoxin, and iron–sulfur proteins. Disulfides, S–S bonds, confer mechanical strength and insolubility of the protein keratin, found in outer skin, hair, and feathers. Sulfur is one of the core chemical elements needed for biochemical functioning and is an elemental macronutrient for all living organisms.

Biological role

Sulfur is an essential component of all living cells. It is either the seventh or eighth most abundant element in the human body by weight, about equal in abundance to potassium, and slightly greater than sodium and chlorine. A 70 kg (150 lb.) human body contains about 140 grams of sulfur.

In plants and animals, the amino acids cysteine and methionine contain most of the sulfur, and the element is present in all polypeptides, proteins, and enzymes that contain these amino acids. In humans, methionine is an essential amino acid that must be ingested. However, save for the vitamins biotin and thiamine, cysteine and all sulfur-containing compounds in the human body can be synthesized from methionine. The enzyme sulfite oxidase is needed for the metabolism of methionine and cysteine in humans and animals.

Disulfide bonds (S-S bonds) between cysteine residues in peptide chains are very important in protein assembly and structure. These covalent bonds between peptide chains confer extra toughness and rigidity. For example, the high strength of feathers and hair is due in part to the high content of S-S bonds with cysteine and sulfur. Eggs are high in sulfur to nourish feather formation in chicks, and the characteristic odor of rotting eggs is due to hydrogen sulfide. The high disulfide bond content of hair and feathers contributes to their indigestibility and to their characteristic disagreeable odor when burned.

Homocysteine and taurine are other sulfur-containing acids that are similar in structure, but not coded by DNA, and are not part of the primary structure of proteins. Many important cellular enzymes use prosthetic groups ending with -SH moieties to handle reactions involving acyl-containing biochemicals: two common examples from basic metabolism are coenzyme A and alpha-lipoic acid. Two of the 13 classical vitamins, biotin, and thiamine, contain sulfur, with the latter being named for its sulfur content.

In intracellular chemistry, sulfur operates as a carrier of reducing hydrogen and its electrons for cellular repair of oxidation. Reduced glutathione, a sulfur-containing tripeptide, is a reducing agent through its sulfhydryl (-SH) moiety derived from cysteine. The thioredoxins, a class of small proteins essential to all known life, use neighboring pairs of reduced cysteines to work as general protein reducing agents, with similar effect.

Methanogenesis, the route to most of the world's methane, is a multistep biochemical transformation of carbon dioxide. This conversion requires several organosulfur cofactors. These include coenzyme M, CH₃SCH₂CH₂SO₃⁻, the immediate precursor to methane.

What is Potassium?

(in 10 minutes)

Hyperkalimia

(too much potassium)

(in 3 minutes)

Hypokalemia

(Too little potassium)

(in 3 minutes)

Potassium is a chemical element with the symbol K (from Neo-Latin kalium) and atomic number 19. Potassium is a silvery-white metal that is soft enough to be cut with a knife with little force. Potassium metal reacts rapidly with atmospheric oxygen to form flaky white potassium peroxide in only seconds of exposure. It was first isolated from potash, the ashes of plants, from which its name derives. In the periodic table, potassium is one of the alkali metals, all of which have a single valence electron in the outer electron shell, that is easily removed to create an ion with a positive charge – a cation, that combines with anions to form salts. Potassium in nature occurs only in ionic salts. Elemental potassium reacts vigorously with water, generating sufficient heat to ignite hydrogen emitted in the reaction, and burning with a lilac-colored flame. It is found dissolved in sea water (which is 0.04% potassium by weight) and occurs in any minerals such as orthoclase, a common constituent of granites and other igneous rocks. Potassium is chemically very similar to sodium, the previous element in group 1 of the periodic table. They have a similar first ionization energy, which allows for each atom to give up its sole outer electron. It was suspected in 1702 that they were distinct elements that combine with the same anions to make similar salts, and was proven in 1807 using electrolysis. Naturally occurring potassium is composed of three isotopes, of which K is radioactive. Traces of K are found in all potassium, and it is the most common radioisotope in the human body.Potassium ions are vital for the functioning of all living cells. The transfer of potassium ions across nerve cell membranes is necessary for normal nerve transmission; potassium deficiency and excess can each result in numerous signs and symptoms, including an abnormal heart rhythm and various electrocardiographic abnormalities. Fresh fruits and vegetables are good dietary sources of potassium. The body responds to the influx of dietary potassium, which raises serum potassium levels, with a shift of potassium from outside to inside cells and an increase in potassium excretion by the kidneys.

Biochemical function

Potassium levels influence multiple physiological processes, including

resting cellular-membrane potential and the propagation of action potentials in neuronal, muscular, and cardiac tissue. Due to the electrostatic and chemical properties, K⁺
ions are larger than Na⁺
ions, and ion channels and pumps in cell membranes can differentiate between the two ions, actively pumping or passively passing one of the two ions while blocking the other.

hormone secretion and action
vascular tone
systemic blood pressure control
gastrointestinal motility
acid–base homeostasis
glucose and insulin metabolism
mineralocorticoid action
renal concentrating ability
fluid and electrolyte balance

Homeostasis

Potassium homeostasis denotes the maintenance of the total body potassium content, plasma potassium level, and the ratio of the intracellular to extracellular potassium concentrations within narrow limits, in the face of pulsatile intake (meals), obligatory renal excretion, and shifts between intracellular and extracellular compartments.

Plasma levels

Plasma potassium is normally kept at 3.5 to 5.0 millimoles (mmol) [or milliequivalents (mEq)] per liter by multiple mechanisms. Levels outside this range are associated with an increasing rate of death from multiple causes, and some cardiac, kidney, and lung diseases progress more rapidly if serum potassium levels are not maintained within the normal range.

An average meal of 40–50 mmol presents the body with more potassium than is present in all plasma (20–25 mmol). However, this surge causes the plasma potassium to rise only 10% at most as a result of prompt and efficient clearance by both renal and extra-renal mechanisms.

Hypokalemia, a deficiency of potassium in the plasma, can be fatal if severe. Common causes are increased gastrointestinal loss (vomiting, diarrhea), and increased renal loss (diuresis). Deficiency symptoms include muscle weakness, paralytic ileus, ECG abnormalities, decreased reflex response; and in severe cases, respiratory paralysis, alkalosis, and cardiac arrhythmia.

Control mechanisms

Potassium content in the plasma is tightly controlled by four basic mechanisms, which have various names and classifications. The four are 1) a reactive negative-feedback system, 2) a reactive feed-forward system, 3) a predictive or circadian system, and 4) an internal or cell membrane transport system. Collectively, the first three are sometimes termed the "external potassium homeostasis system"; and the first two, the "reactive potassium homeostasis system".

The reactive negative-feedback system refers to the system that induces renal secretion of potassium in response to a rise in the plasma potassium (potassium ingestion, shift out of cells, or intravenous infusion.)

The reactive feed-forward system refers to an incompletely understood system that induces renal potassium secretion in response to potassium ingestion prior to any rise in the plasma potassium. This is probably initiated by gut cell potassium receptors that detect ingested potassium and trigger vagal afferent signals to the pituitary gland.

The predictive or circadian system increases renal secretion of potassium during mealtime hours (e.g. daytime for humans, nighttime for rodents) independent of the presence, amount, or absence of potassium ingestion. It is mediated by a circadian oscillator in the suprachiasmatic nucleus of the brain (central clock), which causes the kidney (peripheral clock) to secrete potassium in this rhythmic circadian fashion.

The action of the sodium-potassium pump is an example of primary active transport. The two carrier proteins embedded in the cell membrane on the left are using ATP to move sodium out of the cell against the concentration gradient; The two proteins on the right are using secondary active transport to move potassium into the cell. This process results in reconstitution of ATP.

The ion transport system moves potassium across the cell membrane using two mechanisms. One is active and pumps sodium out of, and potassium into, the cell. The other is passive and allows potassium to leak out of the cell. Potassium and sodium cations influence fluid distribution between intracellular and extracellular compartments by osmotic forces. The movement of potassium and sodium through the cell membrane is mediated by the Na+/K+-ATPase pump. This ion pump uses ATP to pump three sodium ions out of the cell and two potassium ions into the cell, creating an electrochemical gradient and electromotive force across the cell membrane. The highly selective potassium ion channels (which are tetramers) are crucial for hyperpolarization inside neurons after an action potential is triggered, to cite one example. The most recently discovered potassium ion channel is KirBac, which makes a total of five potassium ion channels (KcsA, KirBac1.1, KirBac3.1, KvAP, and MthK) with a determined structure. All five are from prokaryotic species.

Renal filtration, reabsorption, and excretion

Renal handling of potassium is closely connected to sodium handling. Potassium is the major cation (positive ion) inside animal cells [150 mmol/L, (4.8 g)], while sodium is the major cation of extracellular fluid [150 mmol/L, (3.345 g)]. In the kidneys, about 180 liters of plasma is filtered through the glomeruli and into the renal tubules per day. This filtering involves about 600 g of sodium and 33 g of potassium. Since only 1–10 g of sodium and 1–4 g of potassium are likely to be replaced by diet, renal filtering must efficiently reabsorb the remainder from the plasma.

Sodium is reabsorbed to maintain extracellular volume, osmotic pressure, and serum sodium concentration within narrow limits. Potassium is reabsorbed to maintain serum potassium concentration within narrow limits. Sodium pumps in the renal tubules operate to reabsorb sodium. Potassium must be conserved, but because the amount of potassium in the blood plasma is very small and the pool of potassium in the cells is about 30 times as large, the situation is not so critical for potassium. Since potassium is moved passivelyin counter flow to sodium in response to an apparent (but not actual) Donnan equilibrium, the urine can never sink below the concentration of potassium in serum except sometimes by actively excreting water at the end of the processing. Potassium is excreted twice and reabsorbed three times before the urine reaches the collecting tubules. At that point, urine usually has about the same potassium concentration as plasma. At the end of the processing, potassium is secreted one more time if the serum levels are too high.

With no potassium intake, it is excreted at about 200 mg per day until, in about a week, potassium in the serum declines to a mildly deficient level of 3.0–3.5 mmol/L. If potassium is still withheld, the concentration continues to fall until a severe deficiency causes eventual death.

The potassium moves passively through pores in the cell membrane. When ions move through Ion transporters (pumps) there is a gate in the pumps on both sides of the cell membrane and only one gate can be open at once. As a result, approximately 100 ions are forced through per second. Ion channel have only one gate, and there only one kind of ion can stream through, at 10 million to 100 million ions per second. Calcium is required to open the pores, although calcium may work in reverse by blocking at least one of the pores. Carbonyl groups inside the pore on the amino acids mimic the water hydration that takes place in water solution by the nature of the electrostatic charges on four carbonyl groups inside the pore.

Nutrition

(Dietary recommendations)

The U.S. National Academy of Medicine (NAM), on behalf of both the U.S. and Canada, sets Estimated Average Requirements (EARs) and Recommended Dietary Allowances (RDAs), or Adequate Intakes (AIs) for when there is not sufficient information to set EARs and RDAs. Collectively the EARs, RDAs, AIs and ULs are referred to as Dietary Reference Intakes.For both males and females under 9 years of age, the AIs for potassium are: 400 mg of potassium for 0-6-month-old infants, 860 mg of potassium for 7-12-month-old infants, 2,000 mg of potassium for 1-3-year-old children, and 2,300 mg of potassium for 4-8-year-old children. For males 9 years of age and older, the AIs for potassium are: 2,500 mg of potassium for 9-13-year-old males, 3,000 mg of potassium for 14-18-year-old males, and 3,400 mg for males that are 19 years of age and older.For females 9 years of age and older, the AIs for potassium are: 2,300 mg of potassium for 9-18-year-old females, and 2,600 mg of potassium for females that are 19 years of age and older.For pregnant and lactating females, the AIs for potassium are: 2,600 mg of potassium for 14-18-year-old pregnant females, 2,900 mg for pregnant females that are 19 years of age and older; furthermore, 2,500 mg of potassium for 14-18-year-old lactating females, and 2,800 mg for lactating females that are 19 years of age and older. As for safety, the NAM also sets tolerable upper intake levels (ULs) for vitamins and minerals, but for potassium the evidence was insufficient, so no UL was established. As of 2004, most Americans adults consume less than 3,000 mg. Likewise, in the European Union, in particular in Germany and Italy, insufficient potassium intake is somewhat common. The British National Health service recommends a similar intake, saying that adults need 3,500 mg per day and that excess amounts may cause health problems such as stomach pain and diarrhea. Previously the Adequate Intake for adults was set at 4,700 mg per day. In 2019, the National Academies of Sciences, Engineering, and Medicine revised the AI for potassium to 2,600 mg/day for females 19 years and older and 3,400 mg/day for males 19 years and older.

Food sources

Potassium is present in all fruits, vegetables, meat and fish. Foods with high potassium concentrations include yam, parsley, dried apricots, milk, chocolate, all nuts (especially almonds and pistachios), potatoes, bamboo shoots, bananas, avocados, coconut water, soybeans, and bran. The USDA lists tomato paste, orange juice, beet greens, white beans, potatoes, plantains, bananas, apricots, and many other dietary sources of potassium, ranked in descending order according to potassium content. A day's worth of potassium is in 5 plantains or 11 bananas.

Supplementation

Supplements of potassium are most widely used in conjunction with diuretics that block reabsorption of sodium and water upstream from the distal tubule (thiazides and loop diuretics), because this promotes increased distal tubular potassium secretion, with resultant increased potassium excretion. A variety of prescription and over-the counter supplements are available. Potassium chloride may be dissolved in water, but the salty/bitter taste make liquid supplements unpalatable. Typical doses range from 10 mmol (400 mg), to 20 mmol (800 mg). Potassium is also available in tablets or capsules, which are formulated to allow potassium to leach slowly out of a matrix, since very high concentrations of potassium ion that occur adjacent to a solid tablet can injure the gastric or intestinal mucosa. For this reason, non-prescription potassium pills are limited by law in the US to a maximum of 99 mg of potassium.

Since the kidneys are the site of potassium excretion, individuals with impaired kidney function are at risk for hyperkalemia if dietary potassium and supplements are not restricted. The more severe the impairment, the more severe is the restriction necessary to avoid hyperkalemia.

A meta-analysis concluded that a 1640 mg increase in the daily intake of potassium was associated with a 21% lower risk of stroke. Potassium chloride and potassium bicarbonate may be useful to control mild hypertension. In 2017, potassium was the 37th most commonly prescribed medication in the United States, with more than 19 million prescriptions.

Detection by taste buds

Potassium can be detected by taste because it triggers three of the five types of taste sensations, according to concentration. Dilute solutions of potassium ions taste sweet, allowing moderate concentrations in milk and juices, while higher concentrations become increasingly bitter/alkaline, and finally also salty to the taste. The combined bitterness and saltiness of high-potassium solutions makes high-dose potassium supplementation by liquid drinks a palatability challenge.

What is Sodium? Salt?

(in three minutes)

What is the difference between table salt and sea salt?

(in 2 minutes)

Too much sodium? To little sodium?

(in five minutes)

Sodium is a chemical element with the symbol Na (from Latin "natrium") and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable isotope is 23Na. The free metal does not occur in nature, and must be prepared from compounds. Sodium is the sixth most abundant element in the Earth's crust and exists in numerous minerals such as feldspars, sodalite, and rock salt (NaCl). Many salts of sodium are highly water-soluble: sodium ions have been leached by the action of water from the Earth's minerals over eons, and thus sodium and chlorine are the most common dissolved elements by weight in the oceans. Sodium was first isolated by Humphry Davy in 1807 by the electrolysis of sodium hydroxide. Among many other useful sodium compounds, sodium hydroxide (lye) is used in soap manufacture, and sodium chloride (edible salt) is a de-icing agent and a nutrient for animals including humans. Sodium is an essential element for all animals and some plants. Sodium ions are the major cation in the extracellular fluid (ECF) and as such are the major contributor to the ECF osmotic pressure and ECF compartment volume.[citation needed] Loss of water from the ECF compartment increases the sodium concentration, a condition called hypernatremia. Isotonic loss of water and sodium from the ECF compartment decreases the size of that compartment in a condition called ECF hypovolemia. By means of the sodium-potassium pump, living human cells pump three sodium ions out of the cell in exchange for two potassium ions pumped in; comparing ion concentrations across the cell membrane, inside to outside, potassium measures about 40:1, and sodium, about 1:10. In nerve cells, the electrical charge across the cell membrane enables transmission of the nerve impulse—an action potential—when the charge is dissipated; sodium plays a key role in that activity.

Biological role in humans

In humans, sodium is an essential mineral that regulates blood volume, blood pressure, osmotic equilibrium and pH. The minimum physiological requirement for sodium is estimated to range from about 120 milligrams per day in newborns to 500 milligrams per day over the age of 10.

Diet

Sodium chloride is the principal source of sodium in the diet, and is used as seasoning and preservative in such commodities as pickled preserves and jerky; for Americans, most sodium chloride comes from processed foods. Other sources of sodium are its natural occurrence in food and such food additives as monosodium glutamate (MSG), sodium nitrite, sodium saccharin, baking soda (sodium bicarbonate), and sodium benzoate.

Dietary recommendations

The U.S. Institute of Medicine set its Tolerable Upper Intake Level for sodium at 2.3 grams per day, but the average person in the United States consumes 3.4 grams per day. The American Heart Association recommends no more than 1.5 g of sodium per day.

Health

Studies have found that lowering sodium intake by 2 g per day tends to lower systolic blood pressure by about two to four mm Hg. It has been estimated that such a decrease in sodium intake would lead to between 9 and 17% fewer cases of hypertension. Hypertension causes 7.6 million premature deaths worldwide each year. (Note that salt contains about 39.3% sodium—the rest being chlorine and trace chemicals; thus, 2.3 g sodium is about 5.9 g, or 5.3 ml, of salt—about one US teaspoon.)One study found that people with or without hypertension who excreted less than 3 grams of sodium per day in their urine (and therefore were taking in less than 3 g/d) had a higher risk of death, stroke, or heart attack than those excreting 4 to 5 grams per day. Levels of 7 g per day or more in people with hypertension were associated with higher mortality and cardiovascular events, but this was not found to be true for people without hypertension. The US FDA states that adults with hypertension and prehypertension should reduce daily intake to 1.5 g.The renin–angiotensin system regulates the amount of fluid and sodium concentration in the body. Reduction of blood pressure and sodium concentration in the kidney result in the production of renin, which in turn produces aldosterone and angiotensin, which stimulates the reabsorption of sodium back into the bloodstream. When the concentration of sodium increases, the production of renin decreases, and the sodium concentration returns to normal. The sodium ion (Na+) is an important electrolyte in neuron function, and in osmoregulation between cells and the extracellular fluid. This is accomplished in all animals by Na+/K+-ATPase, an active transporter pumping ions against the gradient, and sodium/potassium channels. Sodium is the most prevalent metallic ion in extracellular fluid. Unusually low or high sodium levels in humans are recognized in medicine as hyponatremia and hypernatremia. These conditions may be caused by genetic factors, ageing, or prolonged vomiting or diarrhea.

What is Chlorine (Chloride)?

(in 3 minutes)

The chloride ion /ˈklɔːraɪd/ is the anion (negatively charged ion) Cl−. It is formed when the element chlorine (a halogen) gains an electron or when a compound such as hydrogen chloride is dissolved in water or other polar solvents. Chloride salts such as sodium chloride are often very soluble in water. It is an essential electrolyte located in all body fluids responsible for maintaining acid/base balance, transmitting nerve impulses and regulating fluid in and out of cells. Less frequently, the word chloride may also form part of the "common" name of chemical compounds in which one or more chlorine atoms are covalently bonded. For example, methyl chloride, with the standard name chloromethane (see IUPAC books) is an organic compound with a covalent C−Cl bond in which the chlorine is not an anion.

Chloride has a major physiological significance, which includes regulation of osmotic pressure, electrolyte balance and acid-base homeostasis. Chloride is the most abundant extracellular anion and accounts for around one third of extracellular fluid tonicity. Chloride is an essential electrolyte, playing a key role in maintaining cell homeostasis and transmitting action potentials in neurons. It can flow through chloride channels (including the GABAA receptor) and is transported by KCC2 and NKCC2 transporters. Chloride is usually (though not always) at a higher extracellular concentration, causing it to have a negative reversal potential (around -61 mV at 37 degrees Celsius in a mammalian cell). Characteristic concentrations of chloride in model organisms are: in both E. coli and budding yeast are 10-200 mM (media dependent), in mammalian cell 5-100mM and in blood plasma 100mM. The concentration of chloride in the blood is called serum chloride, and this concentration is regulated by the kidneys. A chloride ion is a structural component of some proteins, e.g., it is present in the amylase enzyme. For these roles, chloride is one of the essential dietary mineral (listed by its element name chlorine). Serum chloride levels are mainly regulated by the kidneys through a variety of transporters that are present along the nephron. Most of the chloride, which is filtered by the glomerulus, is reabsorbed by both proximal and distal tubules (majorly by proximal tubule) by both active and passive transport.

What is Iron?

(in less than 2 minutes)

What is Iron Deficiency Anemia?

(in 1 minute)

Symptoms of Iron Deficiency you must not ignore.

(in 9 minutes)

Iron (/ˈaɪərn/) is a chemical element with symbol Fe (from Latin: ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is by mass the most common element on Earth, right in front of oxygen (32.1% and 30.1%, respectively), forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust.In its metallic state, iron is rare in the Earth's crust, limited mainly to deposition by meteorites. Iron ores, by contrast, are among the most abundant in the Earth's crust, although extracting usable metal from them requires kilns or furnaces capable of reaching 1,500 °C (2,730 °F) or higher, about 500 °C (900 °F) higher than that required to smelt copper. Humans started to master that process in Eurasia only about 2000 BCE,[not verified in body] and the use of iron tools and weapons began to displace copper alloys, in some regions, only around 1200 BCE. That event is considered the transition from the Bronze Age to the Iron Age. In the modern world, iron alloys, such as steel, inox, cast iron and special steels are by far the most common industrial metals, because of their mechanical properties and low cost. Pristine and smooth pure iron surfaces are mirror-like silvery-gray. However, iron reacts readily with oxygen and water to give brown to black hydrated iron oxides, commonly known as rust. Unlike the oxides of some other metals, that form passivating layers, rust occupies more volume than the metal and thus flakes off, exposing fresh surfaces for corrosion. The body of an adult human contains about 4 grams (0.005% body weight) of iron, mostly in hemoglobin and myoglobin. These two proteins play essential roles in vertebrate metabolism, respectively oxygen transport by blood and oxygen storage in muscles. To maintain the necessary levels, human iron metabolism requires a minimum of iron in the diet. Iron is also the metal at the active site of many important redox enzymes dealing with cellular respiration and oxidation and reduction in plants and animals.

Diet

Iron is pervasive, but particularly rich sources of dietary iron include red meat, oysters, lentils, beans, poultry, fish, leaf vegetables, watercress, tofu, chickpeas, black-eyed peas, and blackstrap molasses. Bread and breakfast cereals are sometimes specifically fortified with iron.

Iron provided by dietary supplements is often found as iron (II) fumarate, although iron(II) sulfate is cheaper and is absorbed equally well. Elemental iron, or reduced iron, despite being absorbed at only one-third to two-thirds the efficiency (relative to iron sulfate), is often added to foods such as breakfast cereals or enriched wheat flour. Iron is most available to the body when chelated to amino acids and is also available for use as a common iron supplement. Glycine, the least expensive amino acid, is most often used to produce iron glycinate supplements.

Dietary recommendations

The U.S. Institute of Medicine (IOM) updated Estimated Average Requirements (EARs) and Recommended Dietary Allowances (RDAs) for iron in 2001. The current EAR for iron for women ages 14–18 is 7.9 mg/day, 8.1 for ages 19–50 and 5.0 thereafter (post menopause). For men the EAR is 6.0 mg/day for ages 19 and up. The RDA is 15.0 mg/day for women ages 15–18, 18.0 for 19–50 and 8.0 thereafter. For men, 8.0 mg/day for ages 19 and up. RDAs are higher than EARs so as to identify amounts that will cover people with higher than average requirements. RDA for pregnancy is 27 mg/day and, for lactation, 9 mg/day. For children ages 1–3 years 7 mg/day, 10 for ages 4–8 and 8 for ages 9–13. As for safety, the IOM also sets Tolerable upper intake levels (ULs) for vitamins and minerals when evidence is sufficient. In the case of iron the UL is set at 45 mg/day. Collectively the EARs, RDAs and ULs are referred to as Dietary Reference Intakes. The European Food Safety Authority (EFSA) refers to the collective set of information as Dietary Reference Values, with Population Reference Intake (PRI) instead of RDA, and Average Requirement instead of EAR. AI and UL defined the same as in United States. For women the PRI is 13 mg/day ages 15–17 years, 16 mg/day for women ages 18 and up who are premenopausal and 11 mg/day postmenopausal. For pregnancy and lactation, 16 mg/day. For men the PRI is 11 mg/day ages 15 and older. For children ages 1 to 14 the PRI increases from 7 to 11 mg/day. The PRIs are higher than the U.S. RDAs, with the exception of pregnancy. The EFSA reviewed the same safety question did not establish a UL. Infants may require iron supplements if they are bottle-fed cow's milk. Frequent blood donors are at risk of low iron levels and are often advised to supplement their iron intake. For U.S. food and dietary supplement labeling purposes the amount in a serving is expressed as a percent of Daily Value (%DV). For iron labeling purposes 100% of the Daily Value was 18 mg, and as of May 27, 2016 remained unchanged at 18 mg. Compliance with the updated labeling regulations was required by 1 January 2020, for manufacturers with $10 million or more in annual food sales, and by 1 January 2021, for manufacturers with less than $10 million in annual food sales. During the first six months following the 1 January 2020 compliance date, the FDA plans to work cooperatively with manufacturers to meet the new Nutrition Facts label requirements and will not focus on enforcement actions regarding these requirements during that time. A table of the old and new adult Daily Values is provided at Reference Daily Intake.

Iron deficiency

Iron deficiency is the most common nutritional deficiency in the world. When loss of iron is not adequately compensated by adequate dietary iron intake, a state of latent iron deficiency occurs, which over time leads to iron-deficiency anemia if left untreated, which is characterized by an insufficient number of red blood cells and an insufficient amount of hemoglobin. Children, pre-menopausal women (women of child-bearing age), and people with poor diet are most susceptible to the disease. Most cases of iron-deficiency anemia are mild, but if not treated can cause problems like fast or irregular heartbeat, complications during pregnancy, and delayed growth in infants and children.

Iron overload

Iron uptake is tightly regulated by the human body, which has no regulated physiological means of excreting iron. Only small amounts of iron are lost daily due to mucosal and skin epithelial cell sloughing, so control of iron levels is primarily accomplished by regulating uptake. Regulation of iron uptake is impaired in some people as a result of a genetic defect that maps to the HLA-H gene region on chromosome 6 and leads to abnormally low levels of hepcidin, a key regulator of the entry of iron into the circulatory system in mammals. In these people, excessive iron intake can result in iron overload disorders, known medically as hemochromatosis. Many people have an undiagnosed genetic susceptibility to iron overload, and are not aware of a family history of the problem. For this reason, people should not take iron supplements unless they suffer from iron deficiency and have consulted a doctor. Hemochromatosis is estimated to be the cause of 0.3 to 0.8% of all metabolic diseases of Caucasians.

Overdoses of ingested iron can cause excessive levels of free iron in the blood. High blood levels of free ferrous iron react with peroxides to produce highly reactive free radicals that can damage DNA, proteins, lipids, and other cellular components. Iron toxicity occurs when the cell contains free iron, which generally occurs when iron levels exceed the availability of transferrin to bind the iron. Damage to the cells of the gastrointestinal tract can also prevent them from regulating iron absorption, leading to further increases in blood levels. Iron typically damages cells in the heart, liver and elsewhere, causing adverse effects that include coma, metabolic acidosis, shock, liver failure, coagulopathy, adult respiratory distress syndrome, long-term organ damage, and even death. Humans experience iron toxicity when the iron exceeds 20 milligrams for every kilogram of body mass; 60 milligrams per kilogram is considered a lethal dose. Overconsumption of iron, often the result of children eating large quantities of ferrous sulfate tablets intended for adult consumption, is one of the most common toxicological causes of death in children under six. The Dietary Reference Intake (DRI) sets the Tolerable Upper Intake Level (UL) for adults at 45 mg/day. For children under fourteen years old the UL is 40 mg/day. The medical management of iron toxicity is complicated, and can include use of a specific chelating agent called deferoxamine to bind and expel excess iron from the body.

Cancer

The role of iron in cancer defense can be described as a "double-edged sword" because of its pervasive presence in non-pathological processes. People having chemotherapy may develop iron deficiency and anemia, for which intravenous iron therapy is used to restore iron levels.[180] Iron overload, which may occur from high consumption of red meat, may initiate tumor growth and increase susceptibility to cancer onset, particularly for colorectal cancer.

What is Magnesium?

(in 4 minutes)

Warning signs you need more magnesium

(in 9 minutes)

Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray solid which bears a close physical resemblance to the other five elements in the second column (group 2, or alkaline earth metals) of the periodic table: all group 2 elements have the same electron configuration in the outer electron shell and a similar crystal structure. Magnesium is the ninth most abundant element in the universe. It is produced in large, aging stars from the sequential addition of three helium nuclei to a carbon nucleus. When such stars explode as supernovas, much of the magnesium is expelled into the interstellar medium where it may recycle into new star systems. Magnesium is the eighth most abundant element in the Earth's crust and the fourth most common element in the Earth (after iron, oxygen and silicon), making up 13% of the planet's mass and a large fraction of the planet's mantle. It is the third most abundant element dissolved in seawater, after sodium and chlorine. Magnesium occurs naturally only in combination with other elements, where it invariably has a +2 oxidation state. The free element (metal) can be produced artificially, and is highly reactive (though in the atmosphere, it is soon coated in a thin layer of oxide that partly inhibits reactivity – see passivation). The free metal burns with a characteristic brilliant-white light. The metal is now obtained mainly by electrolysis of magnesium salts obtained from brine, and is used primarily as a component in aluminum-magnesium alloys, sometimes called magnalium or magnelium. Magnesium is less dense than aluminum, and the alloy is prized for its combination of lightness and strength. Magnesium is the eleventh most abundant element by mass in the human body and is essential to all cells and some 300 enzymes. Magnesium ions interact with polyphosphate compounds such as ATP, DNA, and RNA. Hundreds of enzymes require magnesium ions to function. Magnesium compounds are used medicinally as common laxatives, antacids (e.g., milk of magnesia), and to stabilize abnormal nerve excitation or blood vessel spasm in such conditions as eclampsia. Mechanism of action. The important interaction between phosphate and magnesium ions makes magnesium essential to the basic nucleic acid chemistry of all cells of all known living organisms. More than 300 enzymes require magnesium ions for their catalytic action, including all enzymes using or synthesizing ATP and those that use other nucleotides to synthesize DNA and RNA. The ATP molecule is normally found in a chelate with a magnesium ion. Examples of food sources of magnesium: bran muffins, pumpkin seeds, barley, buckwheat flour, low-fat vanilla yogurt, trail mix, halibut steaks, garbanzo beans, lima beans, soybeans, and spinach, spices, nuts, cereals, cocoa and vegetables are rich sources of magnesium. Green leafy vegetables such as spinach are also rich in magnesium. Dietary recommendations. In the UK, the recommended daily values for magnesium are 300 mg for men and 270 mg for women. In the U.S. the Recommended Dietary Allowances (RDAs) are 400 mg for men ages 19–30 and 420 mg for older; for women 310 mg for ages 19–30 and 320 mg for older. Supplementation Numerous pharmaceutical preparations of magnesium and dietary supplements are available. In two human trials magnesium oxide, one of the most common forms in magnesium dietary supplements because of its high magnesium content per weight, was less bioavailable than magnesium citrate, chloride, lactate or aspartate. Metabolism. An adult body has 22–26 grams of magnesium, with 60% in the skeleton, 39% intracellular (20% in skeletal muscle), and 1% extracellular. Serum levels are typically 0.7–1.0 mmol/L or 1.8–2.4 mEq/L. Serum magnesium levels may be normal even when intracellular magnesium is deficient. The mechanisms for maintaining the magnesium level in the serum are varying gastrointestinal absorption and renal excretion. Intracellular magnesium is correlated with intracellular potassium. Increased magnesium lowers calcium and can either prevent hypercalcemia or cause hypocalcemia depending on the initial level. Both low and high protein intake conditions inhibit magnesium absorption, as does the amount of phosphate, phytate, and fat in the gut. Unabsorbed dietary magnesium is excreted in feces; absorbed magnesium is excreted in urine and sweat. Detection in serum and plasma, Magnesium status may be assessed by measuring serum and erythrocyte magnesium concentrations coupled with urinary and fecal magnesium content, but intravenous magnesium loading tests are more accurate and practical. A retention of 20% or more of the injected amount indicates deficiency. No biomarker has been established for magnesium. Magnesium concentrations in plasma or serum may be monitored for efficacy and safety in those receiving the drug therapeutically, to confirm the diagnosis in potential poisoning victims, or to assist in the forensic investigation in a case of fatal overdose. The newborn children of mothers who received parenteral magnesium sulfate during labor may exhibit toxicity with normal serum magnesium levels. Low plasma magnesium (hypomagnesemia) is common: it is found in 2.5–15% of the general population. From 2005 to 2006, 48 percent of the United States population consumed less magnesium than recommended in the Dietary Reference Intake. Other causes are increased renal or gastrointestinal loss, an increased intracellular shift, and proton-pump inhibitor antacid therapy. Most are asymptomatic, but symptoms referable to neuromuscular, cardiovascular, and metabolic dysfunction may occur. Alcoholism is often associated with magnesium deficiency. Chronically low serum magnesium levels are associated with metabolic syndrome, diabetes mellitus type 2, fasciculation, and hypertension. Therapy Intravenous magnesium is recommended by the ACC/AHA/ESC 2006 Guidelines for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death for patients with ventricular arrhythmia associated with torsades de pointes who present with long QT syndrome; and for the treatment of patients with digoxin induced arrhythmias. Magnesium sulfate – intravenous – is used for the management of pre-eclampsia and preeclampsia. Hypomagnesemia, including that caused by alcoholism, is reversible by oral or parenteral magnesium administration depending on the degree of deficiency. There is limited evidence that magnesium supplementation may play a role in the prevention and treatment of migraine. Sorted by type of magnesium salt, other therapeutic applications include: Magnesium sulfate, as the heptahydrate called Epsom salts, is used as bath salts, a laxative, and a highly soluble fertilizer. Magnesium hydroxide, suspended in water, is used in milk of magnesia antacids and laxatives. Magnesium chloride, oxide, gluconate, malate, orotate, glycinate, ascorbate and citrate are all used as oral magnesium supplements. Magnesium borate, magnesium salicylate, and magnesium sulfate are used as antiseptics. Magnesium bromide is used as a mild sedative (this action is due to the bromide, not the magnesium). Magnesium stearate is a slightly flammable white powder with lubricating properties. In pharmaceutical technology, it is used in pharmacological manufacture to prevent tablets from sticking to the equipment while compressing the ingredients into tablet form. Magnesium carbonate powder is used by athletes such as gymnasts, weightlifters, and climbers to eliminate palm sweat, prevent sticking, and improve the grip on gymnastic apparatus, lifting bars, and climbing rocks. Overdose from dietary sources alone is unlikely because excess magnesium in the blood is promptly filtered by the kidneys, and overdose is more likely in the presence of impaired renal function. In spite of this, megadose therapy has caused death in a young child, and severe hypermagnesemia in a woman and a young girl who had healthy kidneys. The most common symptoms of overdose are nausea, vomiting, and diarrhea; other symptoms include hypotension, confusion, slowed heart and respiratory rates, deficiencies of other minerals, coma, cardiac arrhythmia, and death from cardiac arrest.

What is Fluorine? Fluoride?

(in 6 minutes)

What is in your bottled water? (shocking)

(in 17 minutes)

Fluorine is a chemical element with the symbol F and atomic number 9. It is the lightest halogen and exists as a highly toxic pale yellow diatomic gas at standard conditions. As the most electronegative element, it is extremely reactive, as it reacts with all other elements, except for argon, neon, and helium.

Fluoride consumption has been studied as a factor in the following:

Brain

Some research has suggested that high levels of fluoride exposure may adversely affect neurodevelopment in children, but the evidence is of insufficient quality to allow any firm conclusions to be drawn.

Bones

Whilst fluoridated water is associated with decreased levels of fractures in a population, toxic levels of fluoride have been associated with a weakening of bones and an increase in hip and wrist fractures. The U.S. National Research Council concludes that fractures with fluoride levels 1–4 mg/L, suggesting a dose-response relationship, but states that there is "suggestive but inadequate for drawing firm conclusions about the risk or safety of exposures at [2 mg/L]". Consumption of fluoride at levels beyond those used in fluoridated water for a long period of time causes skeletal fluorosis. In some areas, particularly the Asian subcontinent, skeletal fluorosis is endemic. It is known to cause irritable-bowel symptoms and joint pain. Early stages are not clinically obvious, and may be misdiagnosed as (seronegative) rheumatoid arthritis or ankylosing spondylitis.

Kidney

Fluoride induced nephrotoxicity is kidney injury due to toxic levels of serum fluoride, commonly due to release of fluoride from fluorine-containing drugs, such as methoxyflurane. Within the recommended dose, no effects are expected, but chronic ingestion in excess of 12 mg/day are expected to cause adverse effects, and an intake that high is possible when fluoride levels are around 4 mg/L. Those with impaired kidney function are more susceptible to adverse effects. The kidney injury is characterized by failure to concentrate urine, leading to polyuria, and subsequent dehydration with hypernatremia and hyperosmolarity. Inorganic fluoride inhibits adenylate cyclase activity required for antidiuretic hormone effect on the distal convoluted tubule of the kidney. Fluoride also stimulates intrarenal vasodilation, leading to increased medullary blood flow, which interferes with the counter current mechanism in the kidney required for concentration of urine. Fluoride induced nephrotoxicity is dose dependent, typically requiring serum fluoride levels exceeding 50 micromoles per liter (about 1 ppm) to cause clinically significant renal dysfunction, which is likely when the dose of methoxyflurane exceeds 2.5 MAC hours. (Note: "MAC hour" is the multiple of the minimum alveolar concentration (MAC) of the anesthetic used times the number of hours the drug is administered, a measure of the dosage of inhaled anesthetics.) Elimination of fluoride depends on glomerular filtration rate. Thus, patients with chronic kidney disease will maintain serum fluoride for longer period of time, leading to increased risk of fluoride induced nephrotoxicity.

Teeth

The only generally accepted adverse effect of fluoride at levels used for water fluoridation is dental fluorosis, which can alter the appearance of children's teeth during tooth development; this is mostly mild and usually only an aesthetic concern. Compared to unfluoridated water, fluoridation to 1 mg/L is estimated to cause fluorosis in one of every 6 people (range 4–21), and to cause fluorosis of aesthetic concern in one of every 22 people (range 13.6–∞).

Thyroid

Fluoride's suppressive effect on the thyroid is more severe when iodine is deficient, and fluoride is associated with lower levels of iodine. Thyroid effects in humans were associated with fluoride levels 0.05–0.13 mg/kg/day when iodine intake was adequate and 0.01–0.03 mg/kg/day when iodine intake was inadequate. Its mechanisms and effects on the endocrine system remain unclear. Testing on mice shows that the medication gamma-Aminobutyric acid (GABA) can be used to treat fluoride toxicity of the thyroid and return normal function.

Effects on aquatic organisms

Fluoride accumulates in the bone tissues of fish and in the exoskeleton of aquatic invertebrates. The mechanism of fluoride toxicity in aquatic organisms is believed to involve the action of fluoride ions as enzymatic poisons. In soft waters with low ionic content, invertebrates and fishes may suffer adverse effects from fluoride concentration as low as 0.5 mg/L. Negative effects are less in hard waters and seawaters, as the bioavailability of fluoride ions is reduced with increasing water hardness. Seawater contains fluoride at a concentration of 1.3 mg/L.

What is Zinc?

(in 4 minutes)

Too much Zinc can be toxic.

(in 7 minutes)

Zinc is a chemical element with the symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and has a blue-silvery appearance when oxidation is removed. It is the first element in group 12 of the periodic table. In some respects, zinc is chemically similar to magnesium: both elements exhibit only one normal oxidation state (+2), and the Zn²⁺ and Mg²⁺ ions are of similar size. Zinc is the 24th most abundant element in Earth's crust and has five stable isotopes. The most common zinc ore is sphalerite (zinc blende), a zinc sulfide mineral. The largest workable lodes are in Australia, Asia, and the United States. Zinc is refined by froth flotation of the ore, roasting, and final extraction using electricity (electrowinning). Zinc is an essential mineral, including to prenatal and postnatal development. Zinc deficiency affects about two billion people in the developing world and is associated with many diseases. In children, deficiency causes growth retardation, delayed sexual maturation, infection susceptibility, and diarrhea. Enzymes with a zinc atom in the reactive center are widespread in biochemistry, such as alcohol dehydrogenase in humans. Consumption of excess zinc may cause ataxia, lethargy, and copper deficiency.

Biological

Zinc is an essential trace element for humans and other animals, for plants and other microorganisms. Zinc is required for the function of over 300 enzymes and 1000 transcription factors, and is stored and transferred in metallothioneins. It is the second most abundant trace metal in humans after iron and it is the only metal which appears in all enzyme classes. In proteins, zinc ions are often coordinated to the amino acid side chains of aspartic acid, glutamic acid, cysteine and histidine. The theoretical and computational description of this zinc binding in proteins (as well as that of other transition metals) is difficult. Roughly 2–4 grams of zinc are distributed throughout the human body. Most zinc is in the brain, muscle, bones, kidney, and liver, with the highest concentrations in the prostate and parts of the eye. Semen is particularly rich in zinc, a key factor in prostate gland function and reproductive organ growth. Zinc homeostasis of the body is mainly controlled by the intestine. Here, ZIP4 and especially TRPM7 were linked to intestinal zinc uptake essential for postnatal survival. In humans, the biological roles of zinc are ubiquitous. It interacts with "a wide range of organic ligands", and has roles in the metabolism of RNA and DNA, signal transduction, and gene expression. It also regulates apoptosis. A review from 2015 indicated that about 10% of human proteins (~3000) bind zinc, in addition to hundreds more that transport and traffic zinc; a similar in silico study in the plant Arabidopsis thaliana found 2367 zinc-related proteins. In the brain, zinc is stored in specific synaptic vesicles by glutamatergic neurons and can modulate neuronal excitability. It plays a key role in synaptic plasticity and so in learning. Zinc homeostasis also plays a critical role in the functional regulation of the central nervous system. Dysregulation of zinc homeostasis in the central nervous system that results in excessive synaptic zinc concentrations is believed to induce neurotoxicity through mitochondrial oxidative stress (e.g., by disrupting certain enzymes involved in the electron transport chain, including complex I, complex III, and α-ketoglutarate dehydrogenase), the dysregulation of calcium homeostasis, glutamatergic neuronal excitotoxicity, and interference with intraneuronal signal transduction. L- and D-histidine facilitate brain zinc uptake. SLC30A3 is the primary zinc transporter involved in cerebral zinc homeostasis.

Enzymes

Zinc fingers help read DNA sequences. Zinc is an efficient Lewis acid, making it a useful catalytic agent in hydroxylation and other enzymatic reactions. The metal also has a flexible coordination geometry, which allows proteins using it to rapidly shift conformations to perform biological reactions. Two examples of zinc-containing enzymes are carbonic anhydrase and carboxypeptidase, which are vital to the processes of carbon dioxide (CO2) regulation and digestion of proteins, respectively. In vertebrate blood, carbonic anhydrase converts CO2 into bicarbonate and the same enzyme transforms the bicarbonate back into CO2 for exhalation through the lungs. Without this enzyme, this conversion would occur about one million times slower at the normal blood pH of 7 or would require a pH of 10 or more. The non-related β-carbonic anhydrase is required in plants for leaf formation, the synthesis of indole acetic acid (auxin) and alcoholic fermentation. Carboxypeptidase cleaves peptide linkages during digestion of proteins. A coordinate covalent bond is formed between the terminal peptide and a C=O group attached to zinc, which gives the carbon a positive charge. This helps to create a hydrophobic pocket on the enzyme near the zinc, which attracts the non-polar part of the protein being digested. Signaling Zinc has been recognized as a messenger, able to activate signaling pathways. Many of these pathways provide the driving force in aberrant cancer growth. They can be targeted through ZIP transporters.

Zinc serves a purely structural role in zinc fingers, twists and clusters. Zinc fingers form parts of some transcription factors, which are proteins that recognize DNA base sequences during the replication and transcription of DNA. Each of the nine or ten Zn2+ ions in a zinc finger helps maintain the finger's structure by coordinately binding to four amino acids in the transcription factor. The transcription factor wraps around the DNA helix and uses its fingers to accurately bind to the DNA sequence. In blood plasma, zinc is bound to and transported by albumin (60%, low-affinity) and transferrin (10%). Because transferrin also transports iron, excessive iron reduces zinc absorption, and vice versa. A similar antagonism exists with copper. The concentration of zinc in blood plasma stays relatively constant regardless of zinc intake. Cells in the salivary gland, prostate, immune system, and intestine use zinc signaling to communicate with other cells. Zinc may be held in metallothionein reserves within microorganisms or in the intestines or liver of animals. Metallothionein in intestinal cells is capable of adjusting absorption of zinc by 15–40%. However, inadequate or excessive zinc intake can be harmful; excess zinc particularly impairs copper absorption because metallothionein absorbs both metals. The human dopamine transporter contains a high affinity extracellular zinc binding site which, upon zinc binding, inhibits dopamine reuptake and amplifies amphetamine-induced dopamine efflux in vitro. The human serotonin transporter and norepinephrine transporter do not contain zinc binding sites. Some EF-hand calcium binding proteins such as S100 or NCS-1 are also able to bind zinc ions.

Nutrition

The U.S. Institute of Medicine (IOM) updated Estimated Average Requirements (EARs) and Recommended Dietary Allowances (RDAs) for zinc in 2001. The current EARs for zinc for women and men ages 14 and up is 6.8 and 9.4 mg/day, respectively. The RDAs are 8 and 11 mg/day. RDAs are higher than EARs so as to identify amounts that will cover people with higher than average requirements. RDA for pregnancy is 11 mg/day. RDA for lactation is 12 mg/day. For infants up to 12 months the RDA is 3 mg/day. For children ages 1–13 years the RDA increases with age from 3 to 8 mg/day. As for safety, the IOM sets Tolerable upper intake levels (ULs) for vitamins and minerals when evidence is sufficient. In the case of zinc the adult UL is 40 mg/day (lower for children). Collectively the EARs, RDAs, AIs and ULs are referred to as Dietary Reference Intakes (DRIs). The European Food Safety Authority (EFSA) refers to the collective set of information as Dietary Reference Values, with Population Reference Intake (PRI) instead of RDA, and Average Requirement instead of EAR. AI and UL are defined the same as in the United States. For people ages 18 and older the PRI calculations are complex, as the EFSA has set higher and higher values as the phytate content of the diet increases. For women, PRIs increase from 7.5 to 12.7 mg/day as phytate intake increases from 300 to 1200 mg/day; for men the range is 9.4 to 16.3 mg/day. These PRIs are higher than the U.S. RDAs. The EFSA reviewed the same safety question and set its UL at 25 mg/day, which is much lower than the U.S. value. For U.S. food and dietary supplement labeling purposes the amount in a serving is expressed as a percent of Daily Value (%DV). For zinc labeling purposes 100% of the Daily Value was 15 mg, but on May 27, 2016 it was revised to 11 mg. Compliance with the updated labeling regulations was required by 1 January 2020, for manufacturers with $10 million or more in annual food sales, and by 1 January 2021, for manufacturers with less than $10 million in annual food sales. During the first six months following the 1 January 2020 compliance date, the FDA plans to work cooperatively with manufacturers to meet the new Nutrition Facts label requirements and will not focus on enforcement actions regarding these requirements during that time. A table of the old and new adult Daily Values is provided at Reference Daily Intake.

Foods and spices containing zinc

Animal products such as meat, fish, shellfish, fowl, eggs, and dairy contain zinc. The concentration of zinc in plants varies with the level in the soil. With adequate zinc in the soil, the food plants that contain the most zinc are wheat (germ and bran) and various seeds, including sesame, poppy, alfalfa, celery, and mustard. Zinc is also found in beans, nuts, almonds, whole grains, pumpkin seeds, sunflower seeds, and blackcurrant. Plant phytates are particularly found in pulses and cereals and interfere with zinc absorption. Other sources include fortified food and dietary supplements in various forms. A 1998 review concluded that zinc oxide, one of the most common supplements in the United States, and zinc carbonate are nearly insoluble and poorly absorbed in the body. This review cited studies that found lower plasma zinc concentrations in the subjects who consumed zinc oxide and zinc carbonate than in those who took zinc acetate and sulfate salts. For fortification, however, a 2003 review recommended cereals (containing zinc oxide) as a cheap, stable source that is as easily absorbed as the more expensive forms. A 2005 study found that various compounds of zinc, including oxide and sulfate, did not show statistically significant differences in absorption when added as fortificants to maize tortillas.

Deficiency

Nearly two billion people in the developing world are deficient in zinc. Groups at risk include children in developing countries and elderly with chronic illnesses. In children, it causes an increase in infection and diarrhea and contributes to the death of about 800,000 children worldwide per year. The World Health Organization advocates zinc supplementation for severe malnutrition and diarrhea. Zinc supplements help prevent disease and reduce mortality, especially among children with low birth weight or stunted growth. However, zinc supplements should not be administered alone, because many in the developing world have several deficiencies, and zinc interacts with other micronutrients. While zinc deficiency is usually due to insufficient dietary intake, it can be associated with malabsorption, acrodermatitis enteropathica, chronic liver disease, chronic renal disease, sickle cell disease, diabetes, malignancy, and other chronic illnesses. In the United States, a federal survey of food consumption determined that for women and men over the age of 19, average consumption was 9.7 and 14.2 mg/day, respectively. For women, 17% consumed less than the EAR, for men 11%. The percentages below EAR increased with age. The most recent published update of the survey (NHANES 2013–2014) reported lower averages – 9.3 and 13.2 mg/day – again with intake decreasing with age. Symptoms of mild zinc deficiency are diverse. Clinical outcomes include depressed growth, diarrhea, impotence and delayed sexual maturation, alopecia, eye and skin lesions, impaired appetite, altered cognition, impaired immune functions, defects in carbohydrate utilization, and reproductive teratogenesis. Zinc deficiency depresses immunity, but excessive zinc does also.

Despite some concerns, western vegetarians and vegans do not suffer any more from overt zinc deficiency than meat-eaters. Major plant sources of zinc include cooked dried beans, sea vegetables, fortified cereals, soy foods, nuts, peas, and seeds. However, phytates in many whole-grains and fibers may interfere with zinc absorption and marginal zinc intake has poorly understood effects. The zinc chelator phytate, found in seeds and cereal bran, can contribute to zinc malabsorption. Some evidence suggests that more than the US RDA (8 mg/day for adult women; 11 mg/day for adult men) may be needed in those whose diet is high in phytates, such as some vegetarians. The European Food Safety Authority (EFSA) guidelines attempt to compensate for this by recommending higher zinc intake when dietary phytate intake is greater. These considerations must be balanced against the paucity of adequate zinc biomarkers, and the most widely used indicator, plasma zinc, has poor sensitivity and specificity.

What is Silicon (silica)?

(in 4 minutes)

Silicon and Bone Health

(in 4 minutes)

Silicon is a chemical element with the symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic luster, and is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic table: carbon is above it; and germanium, tin, and lead are below it. It is relatively unreactive. Because of its high chemical affinity for oxygen, it was not until 1823 that Jöns Jakob Berzelius was first able to prepare it and characterize it in pure form. Its oxides form a family of anions known as silicates. Its melting and boiling points of 1414 °C and 3265 °C respectively are the second-highest among all the metalloids and nonmetals, being only surpassed by boron. Silicon is the eighth most common element in the universe by mass, but very rarely occurs as the pure element in the Earth's crust. It is most widely distributed in space in cosmic dusts, planetoids, and planets as various forms of silicon dioxide (silica) or silicates. More than 90% of the Earth's crust is composed of silicate minerals, making silicon the second most abundant element in the Earth's crust (about 28% by mass), after oxygen. Most silicon is used commercially without being separated, and often with little processing of the natural minerals. Such use includes industrial construction with clays, silica sand, and stone. Silicates are used in Portland cement for mortar and stucco, and mixed with silica sand and gravel to make concrete for walkways, foundations, and roads. They are also used in whiteware ceramics such as porcelain, and in traditional quartz-based soda-lime glass and many other specialty glasses. Silicon compounds such as silicon carbide are used as abrasives and components of high-strength ceramics. Silicon is the basis of the widely used synthetic polymers called silicones. The late 20th century to early 21st century has been described as the Silicon Age (also known as the Digital Age or Information Age) due to elemental silicon having a large impact on the modern world economy. The relatively small portion of very highly purified elemental silicon used in semiconductor electronics (< 10%) is essential to the metal–oxide–semiconductor (MOS) transistors and integrated circuit chips used in most modern technology (such as computers and cell phones, for example). The most widely used silicon device is the MOSFET (metal–oxide–semiconductor field-effect transistor), which has been manufactured in larger numbers than any other device in history. Free silicon is also used in the steel refining, aluminum-casting, and fine chemical industries (often to make fumed silica).Silicon is an essential element in biology, although only traces are required by animals. However, various sea sponges and microorganisms, such as diatoms and radiolaria, secrete skeletal structures made of silica. Silica is deposited in many plant tissues.

Human nutrition

There is some evidence that silicon is important to human health for their nail, hair, bone, and skin tissues, for example, in studies that demonstrate that premenopausal women with higher dietary silicon intake have higher bone density, and that silicon supplementation can increase bone volume and density in patients with osteoporosis. Silicon is needed for synthesis of elastin and collagen, of which the aorta contains the greatest quantity in the human body, and has been considered an essential element; nevertheless, it is difficult to prove its essentiality, because silicon is very common, and hence, deficiency symptoms are difficult to reproduce. Silicon is currently under consideration for elevation to the status of a "plant beneficial substance by the Association of American Plant Food Control Officials (AAPFCO)."

What is Gallium?

(no known benefit, but it is in us)

(but it is a cool metal, check this out, 12 minutes)

What is Rubidium?

(why is it in us?)

(no known function, but check this out, in 7 minutes)

What is Strontium?

(why is it in us? controversial?)

(in 15 minutes)

The human body absorbs strontium as if it were its lighter congener calcium. Because the elements are chemically very similar, stable strontium isotopes do not pose a significant health threat. The average human has an intake of about two milligrams of strontium a day. In adults, strontium consumed tends to attach only to the surface of bones, but in children, strontium can replace calcium in the mineral of the growing bones and thus lead to bone growth problems. The biological half-life of strontium in humans has variously been reported as from 14 to 600 days, 1,000 days, 18 years, 30 years and, at an upper limit, 49 years. The wide-ranging published biological half-life figures are explained by strontium's complex metabolism within the body. However, by averaging all excretion paths, the overall biological half-life is estimated to be about 18 years. The elimination rate of strontium is strongly affected by age and sex, due to differences in bone metabolism. The drug strontium ranelate aids bone growth, increases bone density, and lessens the incidence of vertebral, peripheral, and hip fractures. However, strontium ranelate also increases the risk of venous thromboembolism, pulmonary embolism, and serious cardiovascular disorders, including myocardial infarction. Its use is therefore now restricted. Its beneficial effects are also questionable, since the increased bone density is partially caused by the increased density of strontium over the calcium which it replaces. Strontium also bioaccumulates in the body. Despite restrictions on strontium ranelate, strontium is still contained in some supplements. There is not much scientific evidence on risks of strontium chloride when taken by mouth. Those with a personal or family history of blood clotting disorders are advised to avoid strontium. Strontium has been shown to inhibit sensory irritation when applied topically to the skin. Topically applied, strontium has been shown to accelerate the recovery rate of the epidermal permeability barrier (skin barrier).

What is Bromine?

(in 5 minutes)

Bromine and Health?

(in 17 minutes)

(beware of bromine tablets)

Large amounts of bromide salts are toxic from the action of soluble bromide ion, causing bromism. However, a clear biological role for bromide ion and hypobromous acid has recently been elucidated, and it now appears that bromine is an essential trace element in humans. Wow, to take it or not, who knows? The role of biological organobromine compounds in sea life such as algae has been known for much longer. As a pharmaceutical, the simple bromide ion (Br−) has inhibitory effects on the central nervous system, and bromide salts were once a major medical sedative, before replacement by shorter-acting drugs.

What is Lead?

(in 6 minutes)

Biological effects

Lead
Hazards
GHS pictograms
GHS Signal word	Danger
GHS hazard statements	H302, H332, H351, H360Df, H373, H410
GHS precautionary statements	P201, P261, P273, P304, P340, P312, P308, P313, P391
NFPA 704 (fire diamond)	0 2 0

Lead has no confirmed biological role, and there is no confirmed safe level of lead exposure. A 2009 Canadian–American study concluded that even at levels that are considered to pose little to no risk, lead may cause "adverse mental health outcomes". Its prevalence in the human body—at an adult average of 120 mg—is nevertheless exceeded only by zinc (2500 mg) and iron (4000 mg) among the heavy metals. Lead salts are very efficiently absorbed by the body. A small amount of lead (1%) is stored in bones; the rest is excreted in urine and feces within a few weeks of exposure. Only about a third of lead is excreted by a child. Continual exposure may result in the bioaccumulation of lead.

Toxicity

Lead is a highly poisonous metal (whether inhaled or swallowed), affecting almost every organ and system in the human body. At airborne levels of 100 mg/m3, it is immediately dangerous to life and health. Most ingested lead is absorbed into the bloodstream. The primary cause of its toxicity is its predilection for interfering with the proper functioning of enzymes. It does so by binding to the sulfhydryl groups found on many enzymes, or mimicking and displacing other metals which act as cofactors in many enzymatic reactions. Among the essential metals that lead interacts with are calcium, iron, and zinc. High levels of calcium and iron tend to provide some protection from lead poisoning; low levels cause increased susceptibility.

Effects

Lead can cause severe damage to the brain and kidneys and, ultimately, death. By mimicking calcium, lead can cross the blood–brain barrier. It degrades the myelin sheaths of neurons, reduces their numbers, interferes with neurotransmission routes, and decreases neuronal growth. In the human body, lead inhibits porphobilinogen synthase and ferrochelatase, preventing both porphobilinogen formation and the incorporation of iron into protoporphyrin IX, the final step in heme synthesis. This causes ineffective heme synthesis and microcytic anemia.

Symptoms of lead poisoning

Symptoms of lead poisoning include nephropathy, colic-like abdominal pains, and possibly weakness in the fingers, wrists, or ankles. Small blood pressure increases, particularly in middle-aged and older people, may be apparent and can cause anemia. Several studies, mostly cross-sectional, found an association between increased lead exposure and decreased heart rate variability. In pregnant women, high levels of exposure to lead may cause miscarriage. Chronic, high-level exposure has been shown to reduce fertility in males. In a child's developing brain, lead interferes with synapse formation in the cerebral cortex, neurochemical development (including that of neurotransmitters), and the organization of ion channels. Early childhood exposure has been linked with an increased risk of sleep disturbances and excessive daytime drowsiness in later childhood. High blood levels are associated with delayed puberty in girls. The rise and fall in exposure to airborne lead from the combustion of tetraethyl lead in gasoline during the 20th century has been linked with historical increases and decreases in crime levels, a hypothesis which is not universally accepted. Exposure sources: Lead exposure is a global issue since lead mining and smelting, and battery manufacturing/ disposal/ recycling, are common in many countries. Lead enters the body via inhalation, ingestion, or skin absorption. Almost all inhaled lead is absorbed into the body; for ingestion, the rate is 20–70%, with children absorbing a higher percentage than adults. Poisoning typically results from ingestion of food or water contaminated with lead, and less commonly after accidental ingestion of contaminated soil, dust, or lead-based paint. Seawater products can contain lead if affected by nearby industrial waters. Fruit and vegetables can be contaminated by high levels of lead in the soils they were grown in. Soil can be contaminated through particulate accumulation from lead in pipes, lead paint, and residual emissions from leaded gasoline. The use of lead for water pipes is a problem in areas with soft or acidic water. Hard water forms insoluble layers in the pipes whereas soft and acidic water dissolves the lead pipes. Dissolved carbon dioxide in the carried water may result in the formation of soluble lead bicarbonate; oxygenated water may similarly dissolve lead as lead(II) hydroxide. Drinking such water, over time, can cause health problems due to the toxicity of the dissolved lead. The harder the water the more calcium bicarbonate and sulfate it will contain, and the more the inside of the pipes will be coated with a protective layer of lead carbonate or lead sulfate. Kymographic recording of the effect of lead acetate on frog heart experimental set up. Ingestion of applied lead-based paint is the major source of exposure for children: a direct source is chewing on old painted window sills. Alternatively, as the applied dry paint deteriorates, it peels, is pulverized into dust and then enters the body through hand-to-mouth contact or contaminated food, water, or alcohol. Ingesting certain home remedies may result in exposure to lead or its compounds. Inhalation is the second major exposure pathway, affecting smokers and especially workers in lead-related occupations. Cigarette smoke contains, among other toxic substances, radioactive lead-210. Skin exposure may be significant for people working with organic lead compounds. The rate of skin absorption is lower for inorganic lead.

Treatment

Treatment for lead poisoning normally involves the administration of dimercaprol and succimer. Acute cases may require the use of disodium calcium edetate, the calcium chelate, and the disodium salt of ethylenediaminetetraacetic acid (EDTA). It has a greater affinity for lead than calcium, with the result that lead chelate is formed by exchange and excreted in the urine, leaving behind harmless calcium.

What is Copper

(in 8 minutes)

Health Benefits of Copper

(in 4 minutes)

Copper Drinking Utensils

(in 4 minutes)

Wilson's Disease

Too much copper

(in 6 minutes)

Copper is a chemical element with the symbol Cu (from Latin: cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish-orange color. Copper is used as a conductor of heat and electricity, as a building material, and as a constituent of various metal alloys, such as sterling silver used in jewelry, cupronickel used to make marine hardware and coins, and constantan used in strain gauges and thermocouples for temperature measurement. Copper is one of the few metals that can occur in nature in a directly usable metallic form (native metals). This led to very early human use in several regions, from c. 8000 BC. Thousands of years later, it was the first metal to be smelted from sulfide ores, c. 5000 BC; the first metal to be cast into a shape in a mold, c. 4000 BC; and the first metal to be purposefully alloyed with another metal, tin, to create bronze, 3500 BC. In the Roman era, copper was mined principally on Cyprus, the origin of the name of the metal, from aсyprium (metal of Cyprus), later corrupted to сuprum (Latin). Coper (Old English) and copper were derived from this, the later spelling first used around 1530. Commonly encountered compounds are copper(II) salts, which often impart blue or green colors to such minerals as azurite, malachite, and turquoise, and have been used widely and historically as pigments. Copper used in buildings, usually for roofing, oxidizes to form a green verdigris (or patina). Copper is sometimes used in decorative art, both in its elemental metal form and in compounds as pigments. Copper compounds are used as bacteriostatic agents, fungicides, and wood preservatives.

Copper is essential to all living organisms as a trace dietary mineral because it is a key constituent of the respiratory enzyme complex cytochrome c oxidase. In mollusks and crustaceans, copper is a constituent of the blood pigment hemocyanin, replaced by the iron-complexed hemoglobin in fish and other vertebrates. In humans, copper is found mainly in the liver, muscle, and bone. The adult body contains between 1.4 and 2.1 mg of copper per kilogram of body weight.

Absorption

Copper is absorbed in the gut, then transported to the liver bound to albumin. After processing in the liver, copper is distributed to other tissues in a second phase, which involves the protein ceruloplasmin, carrying the majority of copper in blood. Ceruloplasmin also carries the copper that is excreted in milk, and is particularly well-absorbed as a copper source. Copper in the body normally undergoes enterohepatic circulation (about 5 mg a day, vs. about 1 mg per day absorbed in the diet and excreted from the body), and the body is able to excrete some excess copper, if needed, via bile, which carries some copper out of the liver that is not then reabsorbed by the intestine.

Dietary recommendations

The U.S. Institute of Medicine (IOM) updated the estimated average requirements (EARs) and recommended dietary allowances (RDAs) for copper in 2001. If there is not sufficient information to establish EARs and RDAs, an estimate designated Adequate Intake (AI) is used instead. The AIs for copper are: 200 μg of copper for 0–6-month-old males and females, and 220 μg of copper for 7–12-month-old males and females. For both sexes, the RDAs for copper are: 340 μg of copper for 1–3 years old, 440 μg of copper for 4–8 years old, 700 μg of copper for 9–13 years old, 890 μg of copper for 14–18 years old and 900 μg of copper for ages 19 years and older. For pregnancy, 1,000 μg. For lactation, 1,300 μg. As for safety, the IOM also sets Tolerable upper intake levels (ULs) for vitamins and minerals when evidence is sufficient. In the case of copper the UL is set at 10 mg/day. Collectively the EARs, RDAs, AIs and ULs are referred to as Dietary Reference Intakes. The European Food Safety Authority (EFSA) refers to the collective set of information as Dietary Reference Values, with Population Reference Intake (PRI) instead of RDA, and Average Requirement instead of EAR. AI and UL defined the same as in United States. For women and men ages 18 and older the AIs are set at 1.3 and 1.6 mg/day, respectively. AIs for pregnancy and lactation is 1.5 mg/day. For children ages 1–17 years the AIs increase with age from 0.7 to 1.3 mg/day. These AIs are higher than the U.S. RDAs. The European Food Safety Authority reviewed the same safety question and set its UL at 5 mg/day, which is half the U.S. value. For U.S. food and dietary supplement labeling purposes the amount in a serving is expressed as a percent of Daily Value (%DV). For copper labeling purposes 100% of the Daily Value was 2.0 mg, but as of May 27, 2016 it was revised to 0.9 mg to bring it into agreement with the RDA. Compliance with the updated labeling regulations was required by 1 January 2020, for manufacturers with $10 million or more in annual food sales, and by 1 January 2021, for manufacturers with less than $10 million in annual food sales. During the first six months following the 1 January 2020 compliance date, the FDA plans to work cooperatively with manufacturers to meet the new Nutrition Facts label requirements and will not focus on enforcement actions regarding these requirements during that time. A table of the old and new adult Daily Values is provided at Reference Daily Intake.

Deficiency

Because of its role in facilitating iron uptake, copper deficiency can produce anemia-like symptoms, neutropenia, bone abnormalities, hypopigmentation, impaired growth, increased incidence of infections, osteoporosis, hyperthyroidism, and abnormalities in glucose and cholesterol metabolism. Conversely, Wilson's disease causes an accumulation of copper in body tissues. Severe deficiency can be found by testing for low plasma or serum copper levels, low ceruloplasmin, and low red blood cell superoxide dismutase levels; these are not sensitive to marginal copper status. The "cytochrome c oxidase activity of leucocytes and platelets" has been stated as another factor in deficiency, but the results have not been confirmed by replication.

What is Aluminum (Aluminium)?

(in 6 minutes)

Aluminum (Dangerous)?

(in 6 minutes)

Biology

Schematic of aluminium absorption by human skin.

Despite its widespread occurrence in the Earth's crust, aluminium has no known function in biology. At pH 6–9 (relevant for most natural waters), aluminium precipitates out of water as the hydroxide and is hence not available; most elements behaving this way have no biological role or are toxic.[Aluminium salts are remarkably nontoxic, aluminium sulfate having an LD50 of 6207 mg/kg (oral, mouse), which corresponds to 435 grams for an 70 kg (150 lb) person.

Toxicity

In most people, aluminium is not as toxic as heavy metals. Aluminium is classified as a non-carcinogen by the United States Department of Health and Human Services. There is little evidence that normal exposure to aluminium presents a risk to healthy adult, and there is evidence of no toxicity if it is consumed in amounts not greater than 40 mg/day per kg of body mass. Most aluminium consumed will leave the body in feces; most of the small part of it that enters the bloodstream, will be excreted via urine.

Effects

Aluminium, although rarely, can cause vitamin D-resistant osteomalacia, erythropoietin-resistant microcytic anemia, and central nervous system alterations. People with kidney insufficiency are especially at a risk. Chronic ingestion of hydrated aluminium silicates (for excess gastric acidity control) may result in aluminium binding to intestinal contents and increased elimination of other metals, such as iron or zinc; sufficiently high doses (>50 g/day) can cause anemia. There are five major aluminium forms absorbed by human body: the free solvated trivalent cation (Al3+(aq)); low-molecular-weight, neutral, soluble complexes (LMW-Al0(aq)); high-molecular-weight, neutral, soluble complexes (HMW-Al0(aq)); low-molecular-weight, charged, soluble complexes (LMW-Al(L)n+/−(aq)); nano and micro-particulates (Al(L)n(s)). They are transported across cell membranes or cell epi-/endothelia through five major routes: (1) paracellular; (2) transcellular; (3) active transport; (4) channels; (5) adsorptive or receptor-mediated endocytosis. During the 1988 Camelford water pollution incident people in Camelford had their drinking water contaminated with aluminium sulfate for several weeks. A final report into the incident in 2013 concluded it was unlikely that this had caused long-term health problems. For 62 years research has found, as of 2018, no good evidence of causal effect. Aluminium increases estrogen-related gene expression in human breast cancer cells cultured in the laboratory. In very high doses, aluminium is associated with altered function of the blood–brain barrier. A small percentage of people have contact allergies to aluminium and experience itchy red rashes, headache, muscle pain, joint pain, poor memory, insomnia, depression, asthma, irritable bowel syndrome, or other symptoms upon contact with products containing aluminium. Exposure to powdered aluminums or aluminium welding fumes can cause pulmonary fibrosis. Fine aluminium powder can ignite or explode, posing another workplace hazard.

The Dangers of Cadmium

(esp. to the fetus)

(in 3 minutes)

What is Cerium?

(in 4 minutes)

What is Barium?

(it has no function in your body, yet it is in you)

(in 6 minutes)

Barium is not an extensively used element. Most is used in drilling fluids for oil and gas wells. It is also used in paint and in glassmaking. All barium compounds are toxic; however, barium sulfate is insoluble and so can be safely swallowed. A suspension of barium sulfate is sometimes given to patients suffering from digestive disorders. This is a ‘barium meal’ or ‘barium enema’. Barium is a heavy element and scatters X-rays, so as it passes through the body the stomach and intestines can be distinguished on an X-ray. Barium carbonate has been used in the past as a rat poison. Barium nitrate gives fireworks a green color.

What is Tin?

(no known function in the human body, why is it in us?)

What is Iodine? (Iodide)

(in 3 minutes)

What is Iodine Deficiency? (hypothyroidism)

(in 6 minutes)

Symptoms of low thyroid levels

(in 3 minutes)

Biological role

Comparison of the iodine content in urine in France (in microgramme/day), for some regions and departments (average levels of urine iodine, measured in micrograms per liter at the end of the twentieth century (1980 to 2000))[86]Iodine is an essential element for life and, at atomic number Z = 53, is the heaviest element commonly needed by living organisms. (Lanthanum and the other lanthanides, as well as tungsten with Z = 74, are used by a few microorganisms.) It is required for the synthesis of the growth-regulating thyroid hormones thyroxine and triiodothyronine (T4 and T3 respectively, named after their number of iodine atoms). A deficiency of iodine leads to decreased production of T3 and T4 and a concomitant enlargement of the thyroid tissue in an attempt to obtain more iodine, causing the disease known as simple goitre. The major form of thyroid hormone in the blood is thyroxine (T4), which has a longer half-life than T3. In humans, the ratio of T4 to T3 released into the blood is between 14:1 and 20:1. T4 is converted to the active T3 (three to four times more potent than T4) within cells by deiodinases (5'-iodinase). These are further processed by decarboxylation and deiodination to produce iodothyronamine (T1a) and thyronamine (T0a'). All three isoforms of the deiodinases are selenium-containing enzymes; thus dietary selenium is essential for T3 production. Iodine accounts for 65% of the molecular weight of T4 and 59% of T3. Fifteen to 20 mg of iodine is concentrated in thyroid tissue and hormones, but 70% of all iodine in the body is found in other tissues, including mammary glands, eyes, gastric mucosa, fetal thymus, cerebro-spinal fluid and choroid plexus, arterial walls, the cervix, and salivary glands. In the cells of those tissues, iodide enters directly by sodium-iodide symporter (NIS). The action of iodine in mammary tissue is related to fetal and neonatal development, but in the other tissues, it is (at least) partially unknown.

Dietary intake

Recommendations by the United States Institute of Medicine are between 110 and 130 µg for infants up to 12 months, 90 µg for children up to eight years, 130 µg for children up to 13 years, 150 µg for adults, 220 µg for pregnant women and 290 µg for lactation. The Tolerable Upper Intake Level (UL) for adults is 1,100 μg/day. This upper limit was assessed by analyzing the effect of supplementation on thyroid-stimulating hormone.[90]The thyroid gland needs no more than 70 μg/day to synthesize the requisite daily amounts of T4 and T3.[4] The higher recommended daily allowance levels of iodine seem necessary for optimal function of a number of body systems, including lactation, gastric mucosa, salivary glands, brain cells, choroid plexus, thymus, and arterial walls. Natural sources of dietary iodine include seafood, such as fish, seaweeds (such as kelp) and shellfish, dairy products and eggs so long as the animals received enough iodine, and plants grown on iodine-rich soil. Iodised salt is fortified with iodine in the form of sodium iodide. As of 2000, the median intake of iodine from food in the United States was 240 to 300 μg/day for men and 190 to 210 μg/day for women. The general US population has adequate iodine nutrition, with women of childbearing age and pregnant women having a possible mild risk of deficiency. In Japan, consumption was considered much higher, ranging between 5,280 μg/day to 13,800 μg/day from dietary seaweed or kombu kelp, often in the form of Kombu Umami extracts for soup stock and potato chips. However, new studies suggest that Japan's consumption is closer to 1,000–3,000 μg/day. The adult UL in Japan was last revised to 3,000 µg/day in 2015. After iodine fortification programs such as iodization of salt have been implemented, some cases of iodine-induced hyperthyroidism have been observed (so-called Jod-Basedow phenomenon). The condition seems to occur mainly in people over forty, and the risk appears higher when iodine deficiency is severe and the initial rise in iodine intake is high.

Deficiency

In areas where there is little iodine in the diet, typically remote inland areas and semi-arid equatorial climates where no marine foods are eaten, iodine deficiency gives rise to hypothyroidism, symptoms of which are extreme fatigue, goiter, mental slowing, depression, weight gain, and low basal body temperatures. Iodine deficiency is the leading cause of preventable intellectual disability, a result that occurs primarily when babies or small children are rendered hypothyroidic by a lack of the element. The addition of iodine to table salt has largely eliminated this problem in wealthier nations, but iodine deficiency remains a serious public health problem in the developing world today. Iodine deficiency is also a problem in certain areas of Europe. Information processing, fine motor skills, and visual problem solving are improved by iodine repletion in moderately iodine-deficient children.

**Iodine**
Hazards
GHS pictograms
GHS Signal word	Danger
GHS hazard statements	H312, H332, H315, H319, H335, H372, H400
GHS precautionary statements	P261, P273, P280, P305, P351, P338, P314
NFPA 704 (fire diamond)	0 3 0

Elemental iodine (I₂) is toxic if taken orally undiluted. The lethal dose for an adult human is 30 mg/kg, which is about 2.1–2.4 grams for a human weighing 70 to 80 kg (even if experiments on rats demonstrated that these animals could survive after eating a 14000 mg/kg dose). Excess iodine can be more cytotoxic in the presence of selenium deficiency. Iodine supplementation in selenium-deficient populations is, in theory, problematic, partly for this reason. The toxicity derives from its oxidizing properties, through which it denaturates proteins (including enzymes).

What is Titanium?

(no function in the human body, but it is in us)

(cool video on the strength of titanium)

(in 12 minutes)

What is Boron?

(in 5 minutes)

What is Selenium?

(in 5 minutes)

More on the function of Selenium?

(in 9 minutes)

Selenium is a chemical element with the symbol Se and atomic number 34. It is a nonmetal (more rarely considered a metalloid) with properties that are intermediate between the elements above and below in the periodic table, sulfur and tellurium, and also has similarities to arsenic. It rarely occurs in its elemental state or as pure ore compounds in the Earth's crust. Selenium—from Ancient Greek σελήνη (selḗnē) "Moon" – was discovered in 1817 by Jöns Jacob Berzelius, who noted the similarity of the new element to the previously discovered tellurium (named for the Earth). Selenium is found in metal sulfide ores, where it partially replaces the sulfur. Commercially, selenium is produced as a byproduct in the refining of these ores, most often during production. Minerals that are pure selenide or selenate compounds are known but rare. The chief commercial uses for selenium today are glassmaking and pigments. Selenium is a semiconductor and is used in photocells. Applications in electronics, once important, have been mostly replaced with silicon semiconductor devices. Selenium is still used in a few types of DC power surge protectors and one type of fluorescent quantum dot. Although trace amounts of selenium are necessary for cellular function in many animals, including humans, both elemental selenium and (especially) selenium salts are toxic in even small doses, causing selenosis. Selenium is listed as an ingredient in many multivitamins and other dietary supplements, including infant formula, and is a component of the antioxidant enzymes glutathione peroxidase and thioredoxin reductase (which indirectly reduce certain oxidized molecules in animals and some plants) as well as in three deiodinase enzymes. Selenium requirements in plants differ by species, with some plants requiring relatively large amounts and others apparently requiring none

Biological role

Although it is toxic in large doses, selenium is an essential micronutrient for animals. In plants, it occurs as a bystander mineral, sometimes in toxic proportions in forage (some plants may accumulate selenium as a defense against being eaten by animals, but other plants, such as locoweed, require selenium, and their growth indicates the presence of selenium in soil). See more on plant nutrition below. Selenium is a component of the unusual amino acids selenocysteine and selenomethionine. In humans, selenium is a trace element nutrient that functions as cofactor for reduction of antioxidant enzymes, such as glutathione peroxidases and certain forms of thioredoxin reductase found in animals and some plants (this enzyme occurs in all living organisms, but not all forms of it in plants require selenium).The glutathione peroxidase family of enzymes (GSH-Px) catalyze certain reactions that remove reactive oxygen species such as hydrogen peroxide and organic hydroperoxides:2 GSH + H2O2----GSH-Px → GSSG + 2 H2OThe thyroid gland and every cell that uses thyroid hormone use selenium, which is a cofactor for the three of the four known types of thyroid hormone deiodinases, which activate and then deactivate various thyroid hormones and their metabolites; the iodothyronine deiodinases are the subfamily of deiodinase enzymes that use selenium as the otherwise rare amino acid selenocysteine. (Only the deiodinase iodotyrosine deiodinase, which works on the last breakdown products of thyroid hormone, does not use selenium.) Selenium may inhibit Hashimoto's disease, in which the body's own thyroid cells are attacked as foreign. A reduction of 21% on TPO antibodies is reported with the dietary intake of 0.2 mg of selenium.[88]Increased dietary selenium reduces the effects of mercury toxicity, although it is effective only at low to modest doses of mercury. Evidence suggests that the molecular mechanisms of mercury toxicity includes the irreversible inhibition of selenoenzymes that are required to prevent and reverse oxidative damage in brain and endocrine tissues. An antioxidant, selenoneine, which is derived from selenium and has been found to be present in the blood of bluefin tuna, is the subject of scientific research regarding its possible roles in inflammatory and chronic diseases, methylmercury detoxification, and oxidative damages. It seems as though when mercury levels in a marine fish rise, so do the selenium levels. To the knowledge of researchers, there are no reports of mercury levels exceeding that of selenium levels in ocean fish.

Evolution in biology

From about three billion years ago, prokaryotic selenoprotein families drive the evolution of selenocysteine, an amino acid. Selenium is incorporated into several prokaryotic selenoprotein families in bacteria, archaea, and eukaryotes as selenocysteine, where selenoprotein peroxiredoxins protect bacterial and eukaryotic cells against oxidative damage. Selenoprotein families of GSH-Px and the deiodinases of eukaryotic cells seem to have a bacterial phylogenetic origin. The selenocysteine-containing form occurs in species as diverse as green algae, diatoms, sea urchins, fish, and chickens. Selenium enzymes are involved in the small reducing molecules glutathione and thioredoxin. One family of selenium-bearing molecules (the glutathione peroxidases) destroys peroxide and repairs damaged peroxidized cell membranes, using glutathione. Another selenium-bearing enzyme in some plants and in animals (thioredoxin reductase) generates reduced thioredoxin, a dithiol that serves as an electron source for peroxidases and also the important reducing enzyme ribonucleotide reductase that makes DNA precursors from RNA precursors. Trace elements involved in GSH-Px and superoxide dismutase enzymes activities, i.e. selenium, vanadium, magnesium, copper, and zinc, may have been lacking in some terrestrial mineral-deficient areas. Marine organisms retained and sometimes expanded their selenoproteomes, whereas the selenoproteomes of some terrestrial organisms were reduced or completely lost. These findings suggest that, with the exception of vertebrates, aquatic life supports selenium use, whereas terrestrial habitats lead to reduced use of this trace element. Marine fishes and vertebrate thyroid glands have the highest concentration of selenium and iodine. From about 500 million years ago, freshwater and terrestrial plants slowly optimized the production of "new" endogenous antioxidants such as ascorbic acid (vitamin C), polyphenols (including flavonoids), tocopherols, etc. A few of these appeared more recently, in the last 50–200 million years, in fruits and flowers of angiosperm plants. In fact, the angiosperms (the dominant type of plant today) and most of their antioxidant pigments evolved during the late Jurassic period. The deiodinase isoenzymes constitute another family of eukaryotic selenoproteins with identified enzyme function. Deiodinases are able to extract electrons from iodides, and iodides from iodothyronines. They are, thus, involved in thyroid-hormone regulation, participating in the protection of thyrocytes from damage by H2O2 produced for thyroid-hormone biosynthesis. About 200 million years ago, new selenoproteins were developed as mammalian GSH-Px enzymes. Nutritional sources of selenium[edit]Dietary selenium comes from meat, nuts, cereals and mushrooms. Brazil nuts are the richest dietary source (though this is soil-dependent, since the Brazil nut does not require high levels of the element for its own needs). The US Recommended Dietary Allowance (RDA) of selenium for teenagers and adults is 55 µg/day. Selenium as a dietary supplement is available in many forms, including multi-vitamins/mineral supplements, which typically contain 55 or 70 µg/serving. Selenium-specific supplements typically contain either 100 or 200 µg/serving.In June 2015, the US Food and Drug Administration (FDA) published its final rule establishing the requirement of minimum and maximum levels of selenium in infant formula. The selenium content in the human body is believed to be in the 13–20 mg range. Certain species of plants are considered indicators of high selenium content of the soil because they require high levels of selenium to thrive. The main selenium indicator plants are Astragalus species (including some locoweeds), prince's plume (Stanleya sp.), woody asters (Xylorhiza sp.), and false goldenweed. Although selenium is an essential trace element, it is toxic if taken in excess. Exceeding the Tolerable Upper Intake Level of 400 micrograms per day can lead to selenosis..This 400 µg Tolerable Upper Intake Level is based primarily on a 1986 study of five Chinese patients who exhibited overt signs of selenosis and a follow up study on the same five people in 1992. The 1992 study actually found the maximum safe dietary Se intake to be approximately 800 micrograms per day (15 micrograms per kilogram body weight), but suggested 400 micrograms per day to avoid creating an imbalance of nutrients in the diet and to accord with data from other countries. In China, people who ingested corn grown in extremely selenium-rich stony coal (carbonaceous shale) have suffered from selenium toxicity. This coal was shown to have selenium content as high as 9.1%, the highest concentration in coal ever recorded. Signs and symptoms of selenosis include a garlic odor on the breath, gastrointestinal disorders, hair loss, sloughing of nails, fatigue, irritability, and neurological damage. Extreme cases of selenosis can exhibit cirrhosis of the liver, pulmonary edema, or death. Elemental selenium and most metallic selenides have relatively low toxicities because of low bioavailability. By contrast, selenates and selenites have an oxidant mode of action similar to that of arsenic trioxide and are very toxic. The chronic toxic dose of selenite for humans is about 2400 to 3000 micrograms of selenium per day. Hydrogen selenide is an extremely toxic, corrosive gas. Selenium also occurs in organic compounds, such as dimethyl selenide, selenomethionine, selenocysteine and methylselenocysteine, all of which have high bioavailability and are toxic in large doses.On 19 April 2009, 21 polo ponies died shortly before a match in the United States Polo Open. Three days later, a pharmacy released a statement explaining that the horses had received an incorrect dose of one of the ingredients used in a vitamin/mineral supplement compound that had been incorrectly prepared by a compounding pharmacy. Analysis of blood levels of inorganic compounds in the supplement indicated the selenium concentrations were 10 to 15 times higher than normal in the blood samples, and 15 to 20 times higher than normal in the liver samples. Selenium was later confirmed to be the toxic factor. Selenium poisoning of water systems may result whenever new agricultural runoff courses through normally dry, undeveloped lands. This process leaches natural soluble selenium compounds (such as selenates) into the water, which may then be concentrated in new "wetlands" as the water evaporates. Selenium pollution of waterways also occurs when selenium is leached from coal flue ash, mining and metal smelting, crude oil processing, and landfill. The resultant high selenium levels in waterways were found to cause congenital disorders in oviparous species, including wetland birds and fish. Elevated dietary methylmercury levels can amplify the harm of selenium toxicity in oviparous species. Relationship between survival of juvenile salmon and concentration of selenium in their tissues after 90 days (Chinook salmon) or 45 days (Atlantic salmon) exposure to dietary selenium. The 10% lethality level (LC10=1.84 µg/g) was derived by applying the biphasic model of Brain and Cousens to only the Chinook salmon data. The Chinook salmon data comprise two series of dietary treatments, combined here because the effects on survival are indistinguishable. In fish and other wildlife, selenium is necessary for life, but toxic in high doses. For salmon, the optimal concentration of selenium is about 1 microgram selenium per gram of whole body weight. Much below that level, young salmon die from deficiency; much above, they die from toxic excess. The Occupational Safety and Health Administration (OSHA) has set the legal limit (permissible exposure limit) for selenium in the workplace at 0.2 mg/m3 over an 8-hour workday. The National Institute for Occupational Safety and Health (NIOSH) has set a Recommended exposure limit (REL) of 0.2 mg/m3 over an 8-hour workday. At levels of 1 mg/m3, selenium is immediately dangerous to life and health.

Deficiency

Selenium deficiency can occur in patients with severely compromised intestinal function, those undergoing total parenteral nutrition, and in those of advanced age (over 90). Also, people dependent on food grown from selenium-deficient soil are at risk. Although New Zealand soil has low levels of selenium, adverse health effects have not been detected in the residents.Selenium deficiency, defined by low (<60% of normal) selenoenzyme activity levels in brain and endocrine tissues, occurs only when a low selenium level is linked with an additional stress, such as high exposures to mercury or increased oxidant stress from vitamin E deficiency. Selenium interacts with other nutrients, such as iodine and vitamin E. The effect of selenium deficiency on health remains uncertain, particularly in relation to Kashin-Beck disease. Also, selenium interacts with other minerals, such as zinc and copper. High doses of Se supplements in pregnant animals might disturb the Zn:Cu ratio and lead to Zn reduction; in such treatment cases, Zn levels should be monitored. Further studies are needed to confirm these interactions. In the regions (e.g. various regions within North America) where low selenium soil levels lead to low concentrations in the plants, some animal species may be deficient unless selenium is supplemented with diet or injection. Ruminants are particularly susceptible. In general, absorption of dietary selenium is lower in ruminants than other animals, and is lower from forages than from grain. Ruminants grazing certain forages, e.g., some white clover varieties containing cyanogenic glycosides, may have higher selenium requirements, presumably because cyanide is released from the aglycone by glucosidase activity in the rumenand glutathione peroxidases is deactivated by the cyanide acting on the glutathione moiety. Neonate ruminants at risk of white muscle disease may be administered both selenium and vitamin E by injection; some of the WMD myopathies respond only to selenium, some only to vitamin E, and some to either.

What is Nickel?

(in 13 minutes)

Beware of this type of cooking ware

(Nickel included)

(in 9 minutes)

Although it was not recognized until the 1970s, nickel is known to play an important role in the biology of some plants, eubacteria, archaebacteria, and fungi. Nickel enzymes such as urease are considered virulence factors in some organisms. Urease catalyzes the hydrolysis of urea to form ammonia and carbamate. The NiFe hydrogenases can catalyze the oxidation of H2 to form protons and electrons, and can also catalyze the reverse reaction, the reduction of protons to form hydrogen gas. A nickel-tetrapyrrole coenzyme, cofactor F430, is present in methyl coenzyme M reductase, which can catalyze the formation of methane, or the reverse reaction, in methanogenic archaea (in +1 oxidation state). One of the carbon monoxide dehydrogenase enzymes consists of an Fe-Ni-S cluster. Other nickel-bearing enzymes include a rare bacterial class of superoxide dismutase and glyoxalase I enzymes in bacteria and several parasitic eukaryotic trypanosomal parasites (in higher organisms, including yeast and mammals, this enzyme contains divalent Zn2+). Dietary nickel may affect human health through infections by nickel-dependent bacteria, but it is also possible that nickel is an essential nutrient for bacteria residing in the large intestine, in effect functioning as a prebiotic. The US Institute of Medicine has not confirmed that nickel is an essential nutrient for humans, so neither a Recommended Dietary Allowance (RDA) nor an Adequate Intake have been established. The Tolerable Upper Intake Level of dietary nickel is 1000 µg/day as soluble nickel salts. Dietary intake is estimated at 70 to 100 µg/day, with less than 10% absorbed. What is absorbed is excreted in urine. Relatively large amounts of nickel – comparable to the estimated average ingestion above – leach into food cooked in stainless steel. For example, the amount of nickel leached after 10 cooking cycles into one serving of tomato sauce averages 88 µg. Nickel released from Siberian Traps volcanic eruptions is suspected of assisting the growth of Methanosarcina, a genus of euryarchaeote archaea that produced methane during the Permian–Triassic extinction event, the biggest extinction event on record.

What is Chromium?

(in 9 minutes)

Health Benefits of Chromium

(in 3 minutes)

Chromium is a chemical element with the symbol Cr and atomic number 24. It is the first element in group 6. It is a steely-grey, lustrous, hard and brittle transition metal. Chromium is the main additive in stainless steel, to which it adds anti-corrosive properties. Chromium is also highly valued as a metal that is able to be highly polished while resisting tarnishing. Polished chromium reflects almost 70% of the visible spectrum, with almost 90% of infrared light being reflected. The name of the element is derived from the Greek word χρῶμα, chrōma, meaning color, because many chromium compounds are intensely colored.

Biological role

The biologically beneficial effects of Chromium (III) continue to be debated. Some experts believe that they reflect pharmacological rather than nutritional responses, while others suggest that they are side effects of a toxic metal. The discussion is marred by elements of negativity and occasionally becomes acrimonious. Chromium is accepted by the U.S. National Institutes of Health as a trace element for its roles in the action of insulin, a hormone critical to the metabolism and storage of carbohydrate, fat and protein. ion whether chromium is essential for healthy people. In contrast, hexavalent chromium (Cr (VI) or Cr6+) is highly toxic and mutagenic when inhaled. Ingestion of chromium (VI) in water has been linked to stomach tumors, and it may also cause allergic contact dermatitis (ACD). Chromium deficiency, involving a lack of Cr (III) in the body, or perhaps some complex of it, such as glucose tolerance factor is controversial. Some studies suggest that the biologically active form of chromium (III) is transported in the body via an oligopeptide called low-molecular-weight chromium-binding substance (LMWCr), which might play a role in the insulin signaling pathway. Chromium content of common foods is generally low (1-13 micrograms per serving). Chromium content of food varies widely due to differences in soil mineral content, growing season, plant cultivar, and contamination during processing. In addition, chromium (and nickel) leach into food cooked in stainless steel, with the effect largest when the cookware is new. Acidic foods such as tomato sauce which are cooked for many hours also exacerbate this effect.

Dietary recommendations

There is disagreement on chromium's status as an essential nutrient. Governmental departments from Australia, New Zealand, India, Japan and the United States consider chromium essential while the European Food Safety Authority (EFSA), representing the European Union, does not. The National Academy of Medicine (NAM) updated the Estimated Average Requirements (EARs) and the Recommended Dietary Allowances (RDAs) for chromium in 2001. For chromium, there was not sufficient information to set EARs and RDAs, so its needs are described as estimates for Adequate Intakes (AIs). The current AIs of chromium for women ages 14 through 50 is 25 μg/day, and the AIs for women ages 50 and above is 20 μg/day. The AIs for women who are pregnant are 30 μg/day, and for women who are lactating, the set AIs are 45 μg/day. The AIs for men ages 14 through 50 are 35 μg/day, and the AIs for men ages 50 and above are 30 μg/day. For children ages 1 through 13, the AIs increase with age from 0.2 μg/day up to 25 μg/day. As for safety, the NAM sets Tolerable Upper Intake Levels (ULs) for vitamins and minerals when the evidence is sufficient. In the case of chromium, there is not yet enough information and hence no UL has been established. Collectively, the EARs, RDAs, AIs and ULs are the parameters for the nutrition recommendation system known as Dietary Reference Intake (DRI). Australia and New Zealand consider chromium to be an essential nutrient, with an AI of 35 μg/day for men, 25 μg/day for women, 30 μg/day for women who are pregnant, and 45 μg/day for women who are lactating. A UL has not been set due to the lack of sufficient data. India considers chromium to be an essential nutrient, with an adult recommended intake of 33 μg/day. Japan also considers chromium to be an essential nutrient, with an AI of 10 μg/day for adults, including women who are pregnant or lactating. A UL has not been set. The EFSA of the European Union however, does not consider chromium to be an essential nutrient; chromium is the only mineral for which the United States and the European Union disagree. For U.S. food and dietary supplement labeling purposes, the amount of the substance in a serving is expressed as a percent of the Daily Value (%DV). For chromium labeling purposes, 100% of the Daily Value was 120 μg. As of May 27, 2016, the percentage of daily value was revised to 35 μg to bring the chromium intake into a consensus with the official Recommended Dietary Allowance. Compliance with the updated labeling regulations was required by 1 January 2020, for manufacturers with $10 million or more in annual food sales, and by 1 January 2021, for manufacturers with less than $10 million in annual food sales. During the first six months following the 1 January 2020 compliance date, the FDA plans to work cooperatively with manufacturers to meet the new Nutrition Facts label requirements and will not focus on enforcement actions regarding these requirements during that time. A table of the old and new adult Daily Values is provided at Reference Daily Intake.

Food sources

Food composition databases such as those maintained by the U.S. Department of Agriculture do not contain information on the chromium content of foods. A wide variety of animal-sourced and vegetable-sourced foods contain chromium. Content per serving is influenced by the chromium content of the soil in which the plants are grown and by feedstuffs fed to animals; also by processing methods, as chromium is leached into foods if processed or cooked in chromium-containing stainless steel equipment. One diet analysis study conducted in Mexico reported an average daily chromium intake of 30 micrograms. An estimated 31% of adults in the United States consume multi-vitamin/mineral dietary supplements which often contain 25 to 60 micrograms of chromium.

Supplementation

Chromium is an ingredient in total parenteral nutrition (TPN) because deficiency can occur after months of intravenous feeding with chromium-free TPN. For this reason, chromium is added to TPN solutions, along with other trace minerals. It is also in nutritional products for preterm infants. Although the mechanism in biological roles for chromium is unclear, in the United States chromium-containing products are sold as non-prescription dietary supplements in amounts ranging from 50 to 1,000 μg. Lower amounts of chromium are also often incorporated into multi-vitamin/mineral supplements consumed by an estimated 31% of adults in the United States. Chemical compounds used in dietary supplements include chromium chloride, chromium citrate, chromium (III) picolinate, chromium (III) polynicotinate, and other chemical compositions. The benefit of supplements has not been proven.

Approved and disapproved health claims

In 2005, the U.S. Food and Drug Administration had approved a Qualified Health Claim for chromium picolinate with a requirement for very specific label wording: "One small study suggests that chromium picolinate may reduce the risk of insulin resistance, and therefore possibly may reduce the risk of type 2 diabetes. FDA concludes, however, that the existence of such a relationship between chromium picolinate and either insulin resistance or type 2 diabetes is highly uncertain." At the same time, in answer to other parts of the petition, the FDA rejected claims for chromium picolinate and cardiovascular disease, retinopathy or kidney disease caused by abnormally high blood sugar levels. In 2010, chromium (III) picolinate was approved by Health Canada to be used in dietary supplements. Approved labeling statements include: a factor in the maintenance of good health, provides support for healthy glucose metabolism, helps the body to metabolize carbohydrates and helps the body to metabolize fats. The European Food Safety Authority (EFSA) approved claims in 2010 that chromium contributed to normal macronutrient metabolism and maintenance of normal blood glucose concentration, but rejected claims for maintenance or achievement of a normal body weight, or reduction of tiredness or fatigue. Given the evidence for chromium deficiency causing problems with glucose management in the context of intravenous nutrition products formulated without chromium, research interest turned to whether chromium supplementation would benefit people who have type 2 diabetes but are not chromium deficient. Looking at the results from four meta-analyses, one reported a statistically significant decrease in fasting plasma glucose levels (FPG) and a non-significant trend in lower hemoglobin A1C. A second reported the same, a third reported significant decreases for both measures, while a fourth reported no benefit for either. A review published in 2016 listed 53 randomized clinical trials that were included in one or more of six meta-analyses. It concluded that whereas there may be modest decreases in FPG and/or HbA1C that achieve statistical significance in some of these meta-analyses, few of the trials achieved decreases large enough to be expected to be relevant to clinical outcome. Two systematic reviews looked at chromium supplements as a mean of managing body weight in overweight and obese people. One, limited to chromium picolinate, a popular supplement ingredient, reported a statistically significant −1.1 kg (2.4 lb.) weight loss in trials longer than 12 weeks. The other included all chromium compounds and reported a statistically significant −0.50 kg (1.1 lb.) weight change. Change in percent body fat did not reach statistical significance. Authors of both reviews considered the clinical relevance of this modest weight loss as uncertain/unreliable. The European Food Safety Authority reviewed the literature and concluded that there was insufficient evidence to support a claim. Chromium is promoted as a sports performance dietary supplement, based on the theory that it potentiates insulin activity, with anticipated results of increased muscle mass, and faster recovery of glycogen storage during post-exercise recovery. A review of clinical trials reported that chromium supplementation did not improve exercise performance or increase muscle strength. The International Olympic Committee reviewed dietary supplements for high-performance athletes in 2018 and concluded there was no need to increase chromium intake for athletes, nor support for claims of losing body fat.

Fresh-water fish

Chromium is naturally present in the environment in trace amounts, but industrial use in rubber and stainless steel manufacturing, chrome plating, dyes for textiles, tanneries and other uses contaminates aquatic systems. In Bangladesh, rivers in or downstream from industrialized areas exhibit heavy metal contamination. Irrigation water standards for chromium are 0.1 mg/L, but some rivers are more than five times that amount. The standard for fish for human consumption is less than 1 mg/kg, but many tested samples were more than five times that amount. Chromium, especially hexavalent chromium, is highly toxic to fish because it is easily absorbed across the gills, readily enters blood circulation, crosses cell membranes and bioconcentrates up the food chain. In contrast, the toxicity of trivalent chromium is very low, attributed to poor membrane permeability and little biomagnification. Acute and chronic exposure to chromium (VI) affects fish behavior, physiology, reproduction and survival. Hyperactivity and erratic swimming have been reported in contaminated environments. Egg hatching and fingerling survival are affected. In adult fish there are reports of histopathological damage to liver, kidney, muscle, intestines, and gills. Mechanisms include mutagenic gene damage and disruptions of enzyme functions. There is evidence that fish may not require chromium, but benefit from a measured amount in diet. In one study, juvenile fish gained weight on a zero chromium diet, but the addition of 500 μg of chromium in the form of chromium chloride or other supplement types, per kilogram of food (dry weight), increased weight gain. At 2,000 μg/kg the weight gain was no better than with the zero chromium diet, and there were increased DNA strand breaks.

Precautions

Water-insoluble chromium (III) compounds and chromium metal are not considered a health hazard, while the toxicity and carcinogenic properties of chromium (VI) have been known for a long time. Because of the specific transport mechanisms, only limited amounts of chromium (III) enter the cells. Acute oral toxicity ranges between 50 and 150 mg/kg. A 2008 review suggested that moderate uptake of chromium (III) through dietary supplements poses no genetic-toxic risk. In the US, the Occupational Safety and Health Administration (OSHA) has designated an air permissible exposure limit (PEL) in the workplace as a time-weighted average (TWA) of 1 mg/m3. The National Institute for Occupational Safety and Health (NIOSH) has set a recommended exposure limit (REL) of 0.5 mg/m3, time-weighted average. The IDLH (immediately dangerous to life and health) value is 250 mg/m3.

Chromium toxicity

The acute oral toxicity for chromium (VI) ranges between 1.5 and 3.3 mg/kg. In the body, chromium (VI) is reduced by several mechanisms to chromium (III) already in the blood before it enters the cells. The chromium (III) is excreted from the body, whereas the chromate ion is transferred into the cell by a transport mechanism, by which also sulfate and phosphate ions enter the cell. The acute toxicity of chromium(VI) is due to its strong oxidant properties. After it reaches the blood stream, it damages the kidneys, the liver and blood cells through oxidation reactions. Hemolysis, renal, and liver failure result. Aggressive dialysis can be therapeutic. The carcinogenity of chromate dust has been known for a long time, and in 1890 the first publication described the elevated cancer risk of workers in a chromate dye company. Three mechanisms have been proposed to describe the genotoxicity of chromium (VI). The first mechanism includes highly reactive hydroxyl radicals and other reactive radicals which are by products of the reduction of chromium (VI) to chromium (III). The second process includes the direct binding of chromium (V), produced by reduction in the cell, and chromium (IV) compounds to the DNA. The last mechanism attributed the genotoxicity to the binding to the DNA of the end product of the chromium (III) reduction. Chromium salts (chromates) are also the cause of allergic reactions in some people. Chromates are often used to manufacture, amongst other things, leather products, paints, cement, mortar and anti-corrosives. Contact with products containing chromates can lead to allergic contact dermatitis and irritant dermatitis, resulting in ulceration of the skin, sometimes referred to as "chrome ulcers". This condition is often found in workers that have been exposed to strong chromate solutions in electroplating, tanning and chrome-producing manufacturers.

What is Manganese?

(in 6 minutes)

Health Benefits of Manganese

(in 4 minutes)

More on the Health Benefits of Manganese

(in 4 minutes)

Manganese is a chemical element with the symbol Mn and atomic number 25. It is not found as a free element in nature; it is often found in minerals in combination with iron. Manganese is a transition metal with a multifaceted array of industrial alloy uses, particularly in stainless steels. Historically, manganese is named for pyrolusite and other black minerals from the region of Magnesia in Greece, which also gave its name to magnesium and the iron ore magnetite. By the mid-18th century, Swedish- German chemist Carl Wilhelm Scheele had used pyrolusite to produce chlorine. Scheele and others were aware that pyrolusite (now known to be manganese dioxide) contained a new element, but they were unable to isolate it. Johan Gottlieb Gahn was the first to isolate an impure sample of manganese metal in 1774, which he did by reducing the dioxide with carbon. Manganese phosphating is used for rust and corrosion prevention on steel. Ionized manganese is used industrially as pigments of various colors, which depend on the oxidation state of the ions. The permanganates of alkali and alkaline earth metals are powerful oxidizers. Manganese dioxide is used as the cathode (electron acceptor) material in zinc-carbon and alkaline batteries. In biology, manganese(II) ions function as cofactors for a large variety of enzymes with many functions. Manganese enzymes are particularly essential in detoxification of superoxide free radicals in organisms that must deal with elemental oxygen. Manganese also functions in the oxygen-evolving complex of photosynthetic plants. While the element is a required trace mineral for all known living organisms, it also acts as a neurotoxin in larger amounts. Especially through inhalation, it can cause manganism, a condition in mammals leading to neurological damage.

Biological role in humans

Manganese is an essential human dietary element. It is present as a coenzyme in several biological processes, which include macronutrient metabolism, bone formation, and free radical defense systems. It is a critical component in dozens of proteins and enzymes. The human body contains about 12 mg of manganese, mostly in the bones. The soft tissue remainder is concentrated in the liver and kidneys. In the human brain, the manganese is bound to manganese metalloproteins, most notably glutamine synthetase in astrocytes.

Toxicity

Excessive exposure or intake may lead to a condition known as manganism, a neurodegenerative disorder that causes dopaminergic neuronal death and symptoms similar to Parkinson's disease.

Dietary recommendations

**Maganese Intake**
Males		Females
Age	AI (mg/day)	Age	AI (mg/day)
1–3	1.2	1–3	1.2
4–8	1.5	4–8	1.5
9–13	1.9	9–13	1.6
14–18	2.2	14–18	1.6
19+	2.3	19+	1.8
			pregnant: 2
			lactating: 2.6

The U.S. Institute of Medicine (IOM) updated Estimated Average Requirements (EARs) and Recommended Dietary Allowances (RDAs) for minerals in 2001. For manganese there was not sufficient information to set EARs and RDAs, so needs are described as estimates for Adequate Intakes (AIs). As for safety, the IOM sets Tolerable upper intake levels (ULs) for vitamins and minerals when evidence is sufficient. In the case of manganese the adult UL is set at 11 mg/day. Collectively the EARs, RDAs, AIs and ULs are referred to as Dietary Reference Intakes (DRIs).

Manganese deficiency

The European Food Safety Authority (EFSA) refers to the collective set of information as Dietary Reference Values, with Population Reference Intake (PRI) instead of RDA, and Average Requirement instead of EAR. AI and UL defined the same as in United States. For people ages 15 and older the AI is set at 3.0 mg/day. AIs for pregnancy and lactation is 3.0 mg/day. For children ages 1–14 years the AIs increase with age from 0.5 to 2.0 mg/day. The adult AIs are higher than the U.S. RDAs. The EFSA reviewed the same safety question and decided that there was insufficient information to set a UL. For U.S. food and dietary supplement labeling purposes the amount in a serving is expressed as a percent of Daily Value (%DV). For manganese labeling purposes 100% of the Daily Value was 2.0 mg, but as of 27 May 2016 it was revised to 2.3 mg to bring it into agreement with the RDA. Compliance with the updated labeling regulations was required by 1 January 2020, for manufacturers with $10 million or more in annual food sales, and by 1 January 2021, for manufacturers with less than $10 million in annual food sales. During the first six months following 1 January 2020 compliance date, the FDA plans to work cooperatively with manufacturers to meet the new Nutrition Facts label requirements and will not focus on enforcement actions regarding these requirements during that time. A table of the old and new adult Daily Values is provided at Reference Daily Intake.

What is Arsenic?
(in 17 minutes)

Deadliest Poisons on Earth

(Arsenic is in there)

(in 7 minutes)

How to detect arsenic poison in you?

(in 7 minutes)

What is Lithium?

(in 4 minutes)

Lithium?

(for bipolar disorders)

(in 7 minutes)

Lithium (from Greek: λίθος, romanized: lithos, lit. 'stone') is a chemical element with the symbol Li and atomic number 3. It is a soft, silvery-white alkali metal. Under standard conditions, it is the lightest metal and the lightest solid element. Like all alkali metals, lithium is highly reactive and flammable, and must be stored in mineral oil. When cut, it exhibits a metallic luster, but moist air corrodes it quickly to a dull silvery gray, then black tarnish. It never occurs freely in nature, but only in (usually ionic) compounds, such as pegmatitic minerals, which were once the main source of lithium. Due to its solubility as an ion, it is present in ocean water and is commonly obtained from brines. Lithium metal is isolated electrolytically from a mixture of lithium chloride and potassium chloride. The nucleus of the lithium atom verges on instability, since the two stable lithium isotopes found in nature have among the lowest binding energies per nucleon of all stable nuclides. Because of its relative nuclear instability, lithium is less common in the solar system than 25 of the first 32 chemical elements even though its nuclei are very light: it is an exception to the trend that heavier nuclei are less common For related reasons, lithium has important uses in nuclear physics. The transmutation of lithium atoms to helium in 1932 was the first fully man-made nuclear reaction, and lithium deuteride serves as a fusion fuel in staged thermonuclear weapons. Lithium and its compounds have several industrial applications, including heat-resistant glass and ceramics, lithium grease lubricants, flux additives for iron, steel and aluminium production, lithium batteries, and lithium-ion batteries. These uses consume more than three-quarters of lithium production. Lithium is present in biological systems in trace amounts; its functions are uncertain. Lithium salts have proven to be useful as a mood-stabilizing drug in the treatment of bipolar disorder in humans.

Medicine

Lithium is useful in the treatment of bipolar disorder. Lithium salts may also be helpful for related diagnoses, such as schizoaffective disorder and cyclic major depression. The active part of these salts is the lithium ion Li+. They may increase the risk of developing Ebstein's cardiac anomaly in infants born to women who take lithium during the first trimester of pregnancy. Lithium has also been researched as a possible treatment for cluster headaches.

What is Mercury?

(it is in you in small amounts)

(in 12 minutes)

What is Cesium?

(it is in you, in small amounts)

What is Molybdenum?

(in 1 minute)

The Health Benefits of Molybdenum

(in 5 minutes)

Molybdenum is a chemical element with the symbol Mo and atomic number 42. The name is from Neo-Latin molybdaenum, which is based on Ancient Greek Μόλυβδος molybdos, meaning lead, since its ores were confused with lead ores. Molybdenum minerals have been known throughout history, but the element was discovered (in the sense of differentiating it as a new entity from the mineral salts of other metals) in 1778 by Carl Wilhelm Scheele. The metal was first isolated in 1781 by Peter Jacob Hjelm. Molybdenum does not occur naturally as a free metal on Earth; it is found only in various oxidation states in minerals. The free element, a silvery metal with a gray cast, has the sixth-highest melting point of any element. It readily forms hard, stable carbides in alloys, and for this reason most of world production of the element (about 80%) is used in steel alloys, including high-strength alloys and superalloys.

Human metabolism and deficiency

Molybdenum is an essential trace dietary element. Four mammalian Mo-dependent enzymes are known, all of them harboring a pterin-based molybdenum cofactor (Moco) in their active site: sulfite oxidase, xanthine oxidoreductase, aldehyde oxidase, and mitochondrial amidoxime reductase. People severely deficient in molybdenum have poorly functioning sulfite oxidase and are prone to toxic reactions to sulfites in foods. The human body contains about 0.07 mg of molybdenum per kilogram of body weight, with higher concentrations in the liver and kidneys and lower in the vertebrae. Molybdenum is also present within human tooth enamel and may help prevent its decay. Acute toxicity has not been seen in humans, and the toxicity depends strongly on the chemical state. Studies on rats show a median lethal dose (LD50) as low as 180 mg/kg for some Mo compounds. Although human toxicity data is unavailable, animal studies have shown that chronic ingestion of more than 10 mg/day of molybdenum can cause diarrhea, growth retardation, infertility, low birth weight, and gout; it can also affect the lungs, kidneys, and liver. Sodium tungstate is a competitive inhibitor of molybdenum. Dietary tungsten reduces the concentration of molybdenum in tissues. Low soil concentration of molybdenum in a geographical band from northern China to Iran results in a general dietary molybdenum deficiency, and is associated with increased rates of esophageal cancer. Compared to the United States, which has a greater supply of molybdenum in the soil, people living in those areas have about 16 times greater risk for esophageal squamous cell carcinoma. Molybdenum deficiency has also been reported as a consequence of non-molybdenum supplemented total parenteral nutrition (complete intravenous feeding) for long periods of time. It results in high blood levels of sulfite and urate, in much the same way as molybdenum cofactor deficiency. However (presumably since pure molybdenum deficiency from this cause occurs primarily in adults), the neurological consequences are not as marked as in cases of congenital cofactor deficiency. Related diseases. A congenital molybdenum cofactor deficiency disease, seen in infants, is an inability to synthesize molybdenum cofactor, the heterocyclic molecule discussed above that binds molybdenum at the active site in all known human enzymes that use molybdenum. The resulting deficiency results in high levels of sulfite and urate, and neurological damage. Copper-molybdenum antagonismHigh levels of molybdenum can interfere with the body's uptake of copper, producing copper deficiency. Molybdenum prevents plasma proteins from binding to copper, and it also increases the amount of copper that is excreted in urine. Ruminants that consume high levels of molybdenum suffer from diarrhea, stunted growth, anemia, and achromotrichia (loss of fur pigment). These symptoms can be alleviated by copper supplements, either dietary and injection. The effective copper deficiency can be aggravated by excess sulfur. Copper reduction or deficiency can also be deliberately induced for therapeutic purposes by the compound ammonium tetrathiomolybdate, in which the bright red anion tetrathiomolybdate is the copper-chelating agent. Tetrathiomolybdate was first used therapeutically in the treatment of copper toxicosis in animals. It was then introduced as a treatment in Wilson's disease, a hereditary copper metabolism disorder in humans; it acts both by competing with copper absorption in the bowel and by increasing excretion. It has also been found to have an inhibitory effect on angiogenesis, potentially by inhibiting the membrane translocation process that is dependent on copper ions. This is a promising avenue for investigation of treatments for cancer, age-related macular degeneration, and other diseases that involve a pathologic proliferation of blood vessels.

Dietary recommendations

In 2000, the then U.S. Institute of Medicine (now the National Academy of Medicine, NAM) updated its Estimated Average Requirements (EARs) and Recommended Dietary Allowances (RDAs) for molybdenum. If there is not sufficient information to establish EARs and RDAs, an estimate designated Adequate Intake (AI) is used instead. An AI of 2 micrograms (μg) of molybdenum per day was established for infants up to 6 months of age, and 3 μg/day from 7 to 12 months of age, both for males and females. For older children and adults, the following daily RDAs have been established for molybdenum: 17 μg from 1 to 3 years of age, 22 μg from 4 to 8 years, 34 μg from 9 to 13 years, 43 μg from 14 to 18 years, and 45 μg for persons 19 years old and older. All these RDAs are valid for both sexes. Pregnant or lactating females from 14 to 50 years of age have a higher daily RDA of 50 μg of molybdenum. As for safety, the NAM sets tolerable upper intake levels (ULs) for vitamins and minerals when evidence is sufficient. In the case of molybdenum, the UL is 2000 μg/day. Collectively the EARs, RDAs, AIs and ULs are referred to as Dietary Reference Intakes (DRIs). The European Food Safety Authority (EFSA) refers to the collective set of information as Dietary Reference Values, with Population Reference Intake (PRI) instead of RDA, and Average Requirement instead of EAR. AI and UL defined the same as in United States. For women and men ages 15 and older the AI is set at 65 μg/day. Pregnant and lactating women have the same AI. For children aged 1–14 years, the AIs increase with age from 15 to 45 μg/day. The adult AIs are higher than the U.S. RDAs, but on the other hand, the European Food Safety Authority reviewed the same safety question and set its UL at 600 μg/day, which is much lower than the U.S. value. For U.S. food and dietary supplement labeling purposes, the amount in a serving is expressed as a percent of Daily Value (%DV). For molybdenum labeling purposes 100% of the Daily Value was 75 μg, but as of May 27, 2016 it was revised to 45 μg. Compliance with the updated labeling regulations was required by 1 January 2020, for manufacturers with $10 million or more in annual food sales, and by 1 January 2021, for manufacturers with less than $10 million in annual food sales. During the first six months following the 1 January 2020 compliance date, the FDA plans to work cooperatively with manufacturers to meet the new Nutrition Facts label requirements and will not focus on enforcement actions regarding these requirements during that time. A table of the old and new adult Daily Values is provided at Reference Daily Intake. Food sources Average daily intake varies between 120 and 240 μg/day, which is higher than dietary recommendations. Pork, lamb, and beef liver each have approximately 1.5 parts per million of molybdenum. Other significant dietary sources include green beans, eggs, sunflower seeds, wheat flour, lentils, cucumbers, and cereal grain.

What is Germanium?

(it is in you)

(in 2 minutes)

What is Cobalt?

(in 7 minutes)

Health Benefits of Cobalt

(in 4 minutes)

Cobalt is a chemical element with the symbol Co and atomic number 27. Like nickel, cobalt is found in the Earth's crust only in chemically combined form, save for small deposits found in alloys of natural meteoric iron. The free element, produced by reductive smelting, is a hard, lustrous, silver-gray metal. Cobalt-based blue pigments (cobalt blue) have been used since ancient times for jewelry and paints, and to impart a distinctive blue tint to glass, but the color was later thought to be due to the known metal bismuth. Miners had long used the name kobold ore (German for goblin ore) for some of the blue-pigment-producing minerals; they were so named because they were poor in known metals, and gave poisonous arsenic-containing fumes when smelted. In 1735, such ores were found to be reducible to a new metal (the first discovered since ancient times), and this was ultimately named for the kobold. Today, some cobalt is produced specifically from one of a number of metallic-lustered ores, such as cobaltite (CoAsS). The element is, however, more usually produced as a by-product of copper and nickel mining. The copper belt in the Democratic Republic of the Congo (DRC) and Zambia yields most of the global cobalt production. World production in 2016 was 116,000 metric tons (114,000 long tons; 128,000 short tons) (according to Natural Resources Canada), and the DRC alone accounted for more than 50%.Cobalt is primarily used in lithium-ion batteries, and in the manufacture of magnetic, wear-resistant and high-strength alloys. The compounds cobalt silicate and cobalt(II) aluminate (CoAl2O4, cobalt blue) give a distinctive deep blue color to glass, ceramics, inks, paints and varnishes. Cobalt occurs naturally as only one stable isotope, cobalt-59. Cobalt-60 is a commercially important radioisotope, used as a radioactive tracer and for the production of high-energy gamma rays. Cobalt is the active center of a group of coenzymes called cobalamins. Vitamin B12, the best-known example of the type, is an essential vitamin for all animals. Cobalt in inorganic form is also a micronutrient for bacteria, algae, and fungi.

Biological role

Cobalt is essential to the metabolism of all animals. It is a key constituent of cobalamin, also known as vitamin B12, the primary biological reservoir of cobalt as an ultra-trace element. Bacteria in the stomachs of ruminant animals convert cobalt salts into vitamin B12, a compound which can only be produced by bacteria or archaea. A minimal presence of cobalt in soils therefore markedly improves the health of grazing animals, and an uptake of 0.20 mg/kg a day is recommended because they have no other source of vitamin B12. Proteins based on cobalamin use corrin to hold the cobalt. Coenzyme B12 features a reactive C-Co bond that participates in the reactions. In humans, B12 has two types of alkyl ligand: methyl and adenosyl. MeB12 promotes methyl (−CH3) group transfers. The adenosyl version of B12 catalyzes rearrangements in which a hydrogen atom is directly transferred between two adjacent atoms with concomitant exchange of the second substituent, X, which may be a carbon atom with substituents, an oxygen atom of an alcohol, or an amine. Methylmalonyl coenzyme A mutase (MUT) converts MMl-CoA to Su-CoA, an important step in the extraction of energy from proteins and fats. Although far less common than other metalloproteins (e.g. those of zinc and iron), other cobaltoproteins are known besides B12. These proteins include methionine aminopeptidase 2, an enzyme that occurs in humans and other mammals that does not use the corrin ring of B12, but binds cobalt directly. Another non-corrin cobalt enzyme is nitrile hydratase, an enzyme in bacteria that metabolizes nitriles. Cobalt is an essential element for life in minute amounts. The LD50 value for soluble cobalt salts has been estimated to be between 150 and 500 mg/kg. In the US, the Occupational Safety and Health Administration (OSHA) has designated a permissible exposure limit (PEL) in the workplace as a time-weighted average (TWA) of 0.1 mg/m3. The National Institute for Occupational Safety and Health (NIOSH) has set a recommended exposure limit (REL) of 0.05 mg/m3, time-weighted average. The IDLH (immediately dangerous to life and health) value is 20 mg/m3. However, chronic cobalt ingestion has caused serious health problems at doses far less than the lethal dose. In 1966, the addition of cobalt compounds to stabilize beer foam in Canada led to a peculiar form of toxin-induced cardiomyopathy, which came to be known as beer drinker's cardiomyopathy. Furthermore, cobalt metal is suspected of causing cancer. It causes respiratory problems when inhaled. It also causes skin problems when touched; after nickel and chromium, cobalt is a major cause of contact dermatitis. These risks are faced by cobalt miners. Cobalt can be effectively absorbed by charred pigs' bones; however, this process is inhibited by copper and zinc, which have greater affinities to bone char.

What is Antimony?

(it is in your body, has no function)

(in 2 minutes)

What is Silver?

Why is it in your body?

(in 9 minutes)

What is Niobium?

(in 9 minutes)

What is Zirconium?

(it is in you in a very small amount)

(in 6 minutes)

What is Lanthanum?

(it is in you)

(in 4 minutes)

What is Tellurium?

(has no known function, but it is in you)

(in 6 minutes)

What is Yttrium?

(it is in you, but has no known function)

(in 4 minutes)

What is Bismuth?

(no known function in the body)

(but it is in you, this is a cool video)

What is Thallium?

(it is in you, the most toxic element on earth)

(in 6 minutes)

What is Indium?

(It too is in you, for what?)

(in 4 minutes)

Where is all the Gold stored?

(small amounts are in you)

(in 5 minutes)

Where is all the Gold made and how?

(in 6 minutes)

While the role of gold in the physiological processes of the human body was unknown for many years, it has recently been determined that gold plays a role in both the health and maintenance of the joints, as well as being a key element in the transmittal of electrical signals throughout the body.

What is Scandium?

(it is in you)

(in 4 minutes)

What is Tantalum?

(this too is in you)

(in 8 minutes)

What is Vanadium

(it has a minor role in your body)

(in 5 minutes)

Vanadium and your Health

(in 3 minutes)

What is Thorium?

(it is radioactive and in you)

(beware of products that contain this element)

(in 15 minutes)

What is Uranium?

(this is in me, yes)

What is Samarium?

(in 5 minutes)

What is Tungsten?

(in 6 minutes)

What is Berrylium?

(in 5 minutes)

What is Lutetium?

(it is in you)

(in 2 minutes)

Possible Treatment for Prostate Cancer?

(in 2 minutes)

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