Essential nutrient

An essential nutrient is a nutrient required for normal body functioning that cannot be synthesized by the body and must be obtained from a dietary source. Some categories of essential nutrients include vitamins, dietary minerals, essential fatty acids, and essential amino acids.

Different species have very different essential nutrients. For example, Vitamin C is essential to humans but not to most other mammals.

Many essential nutrients are toxic in large doses (see hypervitaminosis or the nutrient pages themselves below). Some can be taken in amounts larger than required in a typical diet, with no apparent ill effects. Linus Pauling said of vitamin B₃, (either niacin or niacinamide), "What astonished me was the very low toxicity of a substance that has such very great physiological power. A little pinch, 5 mg, every day, is enough to keep a person from dying of pellagra, but it is so lacking in toxicity that ten thousand times as much can [sometimes] be taken without harm." [cite book|author=Pauling, L.|title=How to Live Longer and Feel Better|year=1986|publisher=Avon Books Inc.|location=New York NY 10019| id=ISBN 0-380-70289-4 Page 24.] A similar statement can be made about vitamin C and some other vitamins.

List of essential nutrients

* Essential human requirements usually not considered to be nutrients:
** Oxygen
** Water
** Sunlight (for synthesis of Vitamin D)
* Essential fatty acids:
** Linolenic acid (the shortest chain omega-3 fatty acid)
** Linoleic acid (the shortest chain omega-6 fatty acid)
* Essential amino acids necessary for all humans:
** Histidine
** Isoleucine
** Lysine
** Leucine
** Methionine
** Phenylalanine
** Threonine
** Tryptophan
** Valine
* Essential amino acids necessary for human children and not adults:
** Arginine
* Vitamins:
** Biotin (vitamin B7, vitamin H)
** Choline (vitamin Bp)
** Folate (folic acid, vitamin B9, vitamin M)
** Niacin (vitamin B3, vitamin P, vitamin PP)
** Pantothenic acid (vitamin B5)
** Riboflavin (vitamin B2, vitamin G)
** Thiamine (vitamin B1)
** Vitamin A (retinol)
** Vitamin B6 (pyridoxine, pyridoxamine, or pyridoxal)
** Vitamin B12 (cobalamin)
** Vitamin C (ascorbic acid)
** Vitamin D (ergocalciferol, or cholecalciferol)
** Vitamin E (tocopherol)
** Vitamin K (naphthoquinoids)
*Dietary mineralsR. Bruce Martin “Metal Ion Toxicity” in Encyclopedia of Inorganic Chemistry, Robert H. Crabtree (Ed), John Wiley & Sons, 2006. DOI: 10.1002/0470862106.ia136]
** Calcium (Ca)
** Chlorine (Cl)
** Cobalt (Co) (as part of Vitamin B-12)
** Copper (Cu) [Hausman, p. 467 ]
** Iodine (I)
** Iron (Fe)
** Magnesium (Mg)
** Manganese (Mn) [Hausman, p. 469 ]
** Molybdenum (Mo)
** Nickel (Ni)
** Phosphorus (P) [ Hausman, p. 470 ]
** Potassium (K)
** Selenium (Se) [ Hausman, p. 432 ]
** Sodium (Na)
** Sulfur (S) numerous roles [Nelson, D. L.; Cox, M. M. "Lehninger, Principles of Biochemistry" 3rd Ed. Worth Publishing: New York, 2000. ISBN 1-57259-153-6.]
** Zinc (Zn) [ Hausman, p. 395 ] The body's requirements vary widely. At one extreme a 70 kg human contains 1.0 kg of calcium but only 3 mg of cobalt. [ [http://web2.airmail.net/uthman/elements_of_body.html Elemental Composition of the Body ] ]

Elements with speculated role in human health

Many elements have been implicated at various times to have a role in human health. For none of these elements has a specific protein or complex been identified:
* Boron (B)
* Chromium (Cr)Mertz, W. 1974. [http://www.ingentaconnect.com/content/cabi/pns/1974/00000033/00000003/art00021 "The newer essential trace elements, chromium, tin, vanadium, nickel and silicon."] Proc. Nutr. Soc. 33 p. 307.] See chromium deficiency
* Silicon (Si)

References

Further reading

*Hausman, P, 1987, "The Right Dose". Rodale Press, Emaus, Pennsylvania. ISBN 0-87857-678-9

See also

* Avitaminosis (vitamin deficiency)
* Dietary Reference Intake
* Dietary supplement
* Illnesses related to poor nutrition
* Malnutrition
* Orthomolecular medicine
* Vitamin poisoning
* Health freedom movement