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[ | Ariboflavinosis | N/D |? |- ! Vitamin B₃ | Niacin, niacinamide | Water | 16.0 mg | Pellagra | 35.0 mg | Liver damage |- ! Vitamin B₅ | Pantothenic acid | Water | 5.0 mg | Paresthesia | N/D | ? |- ! Vitamin B₆ | Pyridoxine, pyridoxamine, pyridoxal | Water | 1.3-1.7 mg | Anaemia | 100 mg | Impairment of proprioception, nerve damage |- ! Vitamin B₇ | Biotin | Water | 30.0 µg | Dermatitis, enteritis | N/D | ? |- ! Vitamin B₉ | Folic acid, folinic acid | Water | 400 µg | align="left"| Deficiency during pregnancy is associated with birth defects, such as neural tube defects | 1,000 µg | Refer to deficiency of Vitamin B₆ |- ! Vitamin B₁₂ | Cyanocobalamin, hydroxycobalamin, methylcobalamin | Water | 2.4 µg | Megaloblastic anaemia | N/D | ? |- ! Vitamin C | Ascorbic acid | Water | 90.0 mg | Scurvy | 2,000 mg | Refer to Vitamin C megadosage |- ! style="whitespace:nowrap;"|Vitamin D | Ergocalciferol, cholecalciferol | Fat | 5.0 µg-10 µg | Rickets and Osteomalacia | 50 µg | Hypervitaminosis D |- ! Vitamin E | Tocopherols, tocotrienols | Fat | 15.0 mg |align="left"| Deficiency is very rare; mild hemolytic anemia in newborn infants. | 1,000 mg | ? |- ! Vitamin K | phylloquinone, menaquinones | Fat | 120 µg | Bleeding diathesis | N/D | ? |}

In nutrition and diseases

Vitamins are essential for the normal growth and development of a multicellular organism. Using the genetic blueprint inherited from its parents, a fetus begins to develop, at the moment of conception, from the nutrients it absorbs. It requires certain vitamins and minerals to be present at certain times. These nutrients facilitate the chemical reactions that produce among other things, skin, bone, and muscle. If there is serious deficiency in one or more of these nutrients, a child may develop a deficiency disease. Even minor deficiencies may cause permanent damage.

For the most part, vitamins are obtained with food, but a few are obtained by other means. For example, microorganisms in the intestine—commonly known as "gut flora"—produce vitamin K and biotin, while one form of vitamin D is synthesized in the skin with the help of natural ultraviolet in sunlight. Humans can produce some vitamins from precursors they consume. Examples include vitamin A, produced from beta carotene, and niacin, from the amino acid tryptophan.

Once growth and development are completed, vitamins remain essential nutrients for the healthy maintenance of the cells, tissues, and organs that make up a multicellular organism; they also enable a multicellular life form to efficiently use chemical energy provided by food it eats, and to help process the proteins, carbohydrates, and fats required for respiration.

Deficiencies

Deficiencies of vitamins are classified as either primary or secondary. A primary deficiency occurs when an organism does not get enough of the vitamin in its food. A secondary deficiency may be due to an underlying disorder that prevents or limits the absorption or use of the vitamin, due to a “lifestyle factor”, such as smoking, excessive alcohol consumption, or the use of medications that interfere with the absorption or use of the vitamin. People who eat a varied diet are unlikely to develop a severe primary vitamin deficiency. In contrast, restrictive diets have the potential to cause prolonged vitamin deficits, which may result in often painful and potentially deadly diseases.

Because human bodies do not store most vitamins, humans must consume them regularly to avoid deficiency. Human bodily stores for different vitamins vary widely; vitamins A, D, and B₁₂ are stored in significant amounts in the human body, mainly in the liver, and an adult human's diet may be deficient in vitamins A and B₁₂ for many months before developing a deficiency condition. Vitamin B₃ is not stored in the human body in significant amounts, so stores may only last a couple of weeks.

Well-known human vitamin deficiencies involve thiamine (beriberi), niacin (pellagra), vitamin C (scurvy) and vitamin D (rickets). In much of the developed world, such deficiencies are rare; this is due to (1) an adequate supply of food; and (2) the addition of vitamins and minerals to common foods, often called fortification.

Recent lines of evidence also suggest a link between nutrition and mental disorders, as evidenced by Lakhan & Vieira (2008).

Side effects and overdose

In large doses, some vitamins have documented side effects that tend to be more severe with a larger dosage. The likelihood of consuming too much of any vitamin from food is remote, but overdosing from vitamin supplementation does occur. At high enough dosages some vitamins cause side effects such as nausea, diarrhea, and vomiting,

When side effects emerge, recovery is often accomplished by reducing the dosage. The concentrations of vitamins an individual can tolerate vary widely, and appear to be related to age and state of health. In the United States, overdose exposure to all formulations of vitamins was reported by 62,562 individuals in 2004 (nearly 80% of these exposures were in children under the age of 6), leading to 53 "major" life-threatening outcomes and 3 deaths—a small number in comparison to the 19,250 people who died of unintentional poisoning of all kinds in the U.S. in the same year (2004).

Supplements

Dietary supplements, often containing vitamins, are used to ensure that adequate amounts of nutrients are obtained on a daily basis, if optimal amounts of the nutrients cannot be obtained through a varied diet. Scientific evidence supporting the benefits of some dietary supplements is well established for certain health conditions, but others need further study. Some research has suggested that supplements do not only provide no tangible health benefits for generally healthy individuals, but may actually increase mortality.

In the United States, advertising for dietary supplements is required to include a disclaimer that the product is not intended to treat, diagnose, mitigate, prevent, or cure disease, and that any health claims have not been evaluated by the Food and Drug Administration. In some cases, dietary supplements may have unwanted effects, especially if taken before surgery, with other dietary supplements or medicines, or if the person taking them has certain health conditions. Vitamin supplements may also contain levels of vitamins many times higher, and in different forms, than one may ingest through food.

Intake of excessive quantities can cause vitamin poisoning, often due to overdose of Vitamin A and Vitamin D (The most common poisoning with multinutrient supplement pills does not involve a vitamin, but is rather due to the mineral iron). Due to toxicity, most common vitamins have recommended upper daily intake amounts.

Governmental regulation of vitamin supplements

Most countries place dietary supplements in a special category under the general umbrella of foods, not drugs. This necessitates that the manufacturer, and not the government, be responsible for ensuring that its dietary supplement products are safe before they are marketed. Unlike drug products, that must explicitly be proven safe and effective for their intended use before marketing, there are often no provisions to "approve" dietary supplements for safety or effectiveness before they reach the consumer. Also unlike drug products, manufacturers and distributors of dietary supplements are not generally required to report any claims of injuries or illnesses that may be related to the use of their products.

Names in current and previous nomenclatures

The reason the set of vitamins seems to skip directly from E to K is that the vitamins corresponding to "letters" F-J were either reclassified over time, discarded as false leads, or renamed because of their relationship to "vitamin B", which became a "complex" of vitamins. The German-speaking scientists who isolated and described vitamin K (in addition to naming it as such) did so because the vitamin is intimately involved in the Koagulation of blood following wounding. At the time, most (but not all) of the letters from F through J were already designated, so the use of the letter K was considered quite reasonable.

The following table lists chemicals that had previously been classified as vitamins, as well as the earlier names of vitamins that later became part of the B-complex:

See also

• Nutrition
  • Vitamin deficiency
  • Dietary minerals
  • Essential amino acids
  • Essential nutrients
  • Nootropics
  • Nutrients
• Antioxidant
• Dietary supplement
• Dieteticsε Ζ ζ Η η Θ θ Ι ι Κ κ Λ λ Μ μ Ν ν Ξ ξ Ο ο Π π Ρ ρ Σ σ ς Τ τ Υ υ Φ φ Χ χ Ψ ψ Ω ω • Template:Polytonic • (polytonic list)

Cyrillic: А а Б б В в Г г Ґ ґ Ѓ ѓ Д д Ђ ђ Е е Ё ё Є є Ж ж З з Ѕ ѕ И и І і Ї ї Й й Ј ј К к Ќ ќ Л л Љ љ М м Н н Њ њ О о П п Р р С с Т т Ћ ћ У у Ў ў Ф ф Х х Ц ц Ч ч Џ џ Ш ш Щ щ Ъ ъ Ы ы Ь ь Э э Ю ю Я я

• Fat soluble vitamins
• Health freedom movement
• Illnesses related to poor nutrition
• Megavitamin therapy
• Orthomolecular medicine
• Pharmacology
• Vitamin poisoning (overdose)
• Whole food supplements

References

1. Plain type indicates Adequate Intakes (A/I). "The AI is believed to cover the needs of all individuals, but a lack of data prevent being able to specify with confidence the percentage of individuals covered by this intake" (see Dietary Reference Intakes: Vitamins).
2. Vitamin and Mineral Supplement Fact Sheets Vitamin B₆
3. Vitamin and Mineral Supplement Fact Sheets Vitamin B₁₂
4. Value represents suggested intake without adequate sunlight exposure (see Dietary Reference Intakes: Vitamins).
5. ^ The Merck Manual: Nutritional Disorders: Vitamin Introduction Please select specific vitamins from the list at the top of the page.
6. Dr. Leonid A. Gavrilov, Pieces of the Puzzle: Aging Research Today and Tomorrow
7. ^ Cite error: The named reference RDA was invoked but never defined (see the help page).
8. ^ Cite error: The named reference GOVa was invoked but never defined (see the help page).
9. Lakhan SE; Vieira KF. Nutritional therapies for mental disorders. Nutrition Journal 2008;7(2).
10. Institute of Medicine. Food and Nutrition Board. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. National Academy Press, Washington, DC, 2001.
11. J.G. Hardman et al., eds., Goodman and Gilman's Pharmacological Basis of Therapeutics, 10th ed., p.992.
12. Rohde LE, de Assis MC, Rabelo ER (2007). "Dietary vitamin K intake and anticoagulation in elderly patients". Curr Opin Clin Nutr Metab Care. 10 (1): 1–5. doi:10.1097/MCO.0b013e328011c46c. PMID 17143047. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
13. Healthier Kids Section: What to take and how to take it.
14. 2004 Annual Report of the American Association of Poison Control Centers Toxic Exposure Surveillance System.
15. National Center for Health Statistics
16. ^ Use and Safety of Dietary Supplements NIH office of Dietary Supplements.
17. Bjelakovic G; et al. (2007). "Mortality in randomized trials of antioxidant supplements for primary and secondary prevention: systematic review and meta-analysis". JAMA. 297 (8): 842–57. doi:10.1001/jama.297.8.842. PMID 17327526. {{cite journal}}: Explicit use of et al. in: |author= (help)
18. Jane Higdon Vitamin E recommendations at Linus Pauling Institute's Micronutrient Information Center
19. Overview of Dietary Supplements
20. Illnesses and Injuries Associated with the Use of Selected Dietary Supplements U. S. FDA Center for Food Safety and Applied Nutrition
21. ^ Every Vitamin Page All Vitamins and Pseudo-Vitamins. Compiled by David Bennett.
22. ^ Vitamins and minerals - names and facts
23. ^ Michael W. Davidson (2004) Anthranilic Acid (Vitamin L) Florida State University. Accessed 20-02-07

General References Include:

• Stedman's Medical Dictionary. Ed. Maureen Barlow Pugh et.al. 27th ed. Baltimore: Lippincott Williams & Wilkins, 2000.
• Donatelle, Rebecca J. Health: The Basics. 6th ed. San Francisco: Pearson Education, Inc. 2005.

External links

• USDA RDA chart in PDF format
• Health Canada Dietary Reference Intakes Reference Chart for Vitamins
• NIH Office of Dietary Supplements: Fact Sheets
• NIH Office of Dietary Supplements. Dietary Supplements: Background Information

• Essential nutrients
• Nutrition
• Vitamins