Essential nutrient
From Wikipedia, the free encyclopedia
An essential nutrient is a nutrient required for normal body functioning that either cannot be synthesized by the body at all, or cannot be synthesized in amounts adequate for good health (e.g. niacin, choline), and thus 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, most mammals synthesize their own ascorbic acid, and it is therefore not considered an essential nutrient for such species. It is, however, an essential nutrient for human beings, who require external sources of ascorbic acid (known as Vitamin C in the context of nutrition).
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."[1]
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[edit] List of essential nutrients
- Essential human requirements usually not considered to be nutrients:
- Essential fatty acids:
- α-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:
- Essential amino acids necessary for human children but not adults:
- 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 minerals[2]
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.
[edit] 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:
[edit] References
- ^ Pauling, L. (1986). How to Live Longer and Feel Better. New York NY 10019: Avon Books Inc.. ISBN 0-380-70289-4. Page 24.
- ^ R. Bruce Martin “Metal Ion Toxicity” in Encyclopedia of Inorganic Chemistry, Robert H. Crabtree (Ed), John Wiley & Sons, 2006. DOI: 10.1002/0470862106.ia136
- ^ Hausman, p. 467
- ^ Hausman, p. 469
- ^ a b c Mertz, W. 1974. The newer essential trace elements, chromium, tin, vanadium, nickel and silicon. Proc. Nutr. Soc. 33 p. 307.
- ^ Hausman, p. 470
- ^ Hausman, p. 432
- ^ Nelson, D. L.; Cox, M. M. "Lehninger, Principles of Biochemistry" 3rd Ed. Worth Publishing: New York, 2000. ISBN 1-57259-153-6.
- ^ Hausman, p. 395
[edit] Further reading
- Hausman, P, 1987, The Right Dose. Rodale Press, Emaus, Pennsylvania. ISBN 0-87857-678-9
