Vitamin

A vitamin is an organic moleculerequired by a living organismin minute amounts for proper health. An organism deprived of all sources of a particular vitamin will eventually suffer from diseasesymptomsspecific to that vitamin.

Vitamins can be classified as either watersoluble, which means they dissolve easily in water, or fatsoluble, which means they are absorbed through the intestinal tractwith the help of lipids.

In general, an organism must obtain vitamins or their metabolic precursors from outside the body, most often from the organism's diet. Examples of vitamins that the humanbody can derive from precursors include vitamin A, which can be produced from beta carotene; niacin from the amino acidtryptophan; and vitamin D through exposure of skinto ultravioletlight.

The term vitamin does not encompass other essential nutrientssuch as dietary minerals, essential fatty acids, or essential amino acids, nor is it used for the large number of other nutrients that merely promote health, but are not strictly essential.

The word vitamin was coined by the PolishbiochemistCasimir Funkin 1912. Vita in Latin is life and the -amin suffix is short for amine; at the time it was thought that all vitamins were amines. Though this is now known to be incorrect, the name has stuck.

History

The value of eating certain foods to maintain health was recognized long before vitamins were identified. The ancient Egyptiansknew that feeding a patient liverwould help cure night blindness, now known to be caused by a vitamin Adeficiency. In 1747, the ScottishsurgeonJames Linddiscovered that citrusfoods helped prevent scurvy, a particularly deadly disease in which collagenis not properly formed, and characterized by poor wound healing, bleeding of the gums, and severe pain. In 1753, Lind published his Treatise on the Scurvy. His discovery, however, was not widely accepted. In the Royal Navy's Arcticexpeditions in the 19th century, for example, it was widely believed that scurvy was prevented by good hygieneon board ship, regular exercise, and maintaining the moraleof the crew, rather than by a diet of fresh food, so that Navy expeditions continued to be plagued by scurvy. At the time Robert Falcon Scott made his two expeditions to the Antarcticin the early 20th century, the prevailing medical theory was that scurvy was caused by "tainted" canned food.

In 1881, Russiansurgeon Nikolai Lunin fed miceupon an artificial mixture of all the separate constituents of milkknown at that time, namely the proteins, fats, carbohydrates, and salts. They died, while the mice fed by milk itself developed normally. He made a conclusion that "a natural food such as milk must therefore contain besides these known principal ingredients small quantities of unknown substances essential to life" [1] However, his conclusion was rejected by other researchers who were unable to reproduce his results. One difference was that he used table sugar (sucrose), while other researchers used milk sugar (lactose) which still contained small amounts of vitamin B.

In 1905, William Fletcherdiscovered that eating unpolished riceinstead of polished helped prevent the disease beriberi. The following year, Frederick Hopkinspostulated that foods contained "accessory factors"—in addition to proteins, carbohydrates, fats, etc.—that are necessary to the human body. When Casimir Funkisolated the water-soluble complex of micronutrients whose bioactivity Fletcher had identified, he proposed that it be named "Vitamine". The name soon became synonymous with Hopkins' "accessory factors", and by the time it was shown that not all vitamins were amines, the word was already ubiquitous. In 1920, Jack Cecil Drummondproposed that the final "e" be dropped, to deemphasize the "amine" reference, after the discovery that vitamin Chad no amine component, and the name has been "vitamin" ever since.

Throughout the early 1900s, scientists were able to isolate and identify a number of vitamins by depriving animals of them. Initially, lipid from fish oilwas used to cure ricketsin rats, and the fat-soluble nutrient was called "antirachitic A". The irony here is that the first "vitamin" bioactivity ever isolated, which cured rickets, was initially called vitamine A, this bioactivity is now called vitamin D, which is subject to the semantic debate that vitamin D is not truly a vitamin because it is a steroidderivative. What we now call "vitamin A" was identified in fish oil because it was inactivated by ultravioletlight. Most of what we now recognize as the water-soluble organic micronutrients were initially referred to as just one entity, "vitamin B".

Human vitamins

In humans, there are thirteen vitamins, divided into two groups, the four fat soluble vitamins (A, D, E and K) and the nine water soluble vitamins (eight B vitamins and vitamin C).

• = Folic acid (Vitamin B₉) deficiency in pregnant womenis associated with birth defects, and has links to canceras well.

Some of the vitamins are known by other names in older literature. Vitamin B₂is also referred to as Vitamin G. Vitamin B₇, or biotinis also referred to as "Vitamin H." Vitamin B₉, or folic acid and other folates such "Vitamin M (Monkey antianemia factor) -Pteryl-tri-glutamic acid" are refered to as Folicin. Vitamin B₃is also referred to as "Vitamin PP", a name derived from the obsolete term "pellagra-preventing factor". Many other essential dietary substances were originally called vitamins and are now classified differently.

Other possible Vitamins are DMAE (fish,eggs,soy,brains), Lipoic acid (liver), Folinic acid (liver), Bioptrin (fish, liver), PPQ (below) and Coenzyme Q (meat, yogurt, soy)

Vitamin deficiency and excess

An organism can survive for some time without vitamins, although prolonged vitamin deficit results in a diseasestate, often painful and potentially deadly. Body stores for different vitamins can vary widely; an adult may be deficient in Vitamins A or B₁₂ for a year or more before developing a deficiency condition, while Vitamin B₁ stores may only last a couple of weeks.

Fat-soluble vitamins may be stored in the body and can cause toxicity when taken in excess. Water-soluble vitamins are not stored in the body, with the exception of Vitamin B₁₂, which is stored in the liver.

Pseudo-vitamins

• Vitamin F was the designation originally given to essential fatty acidsthat the body cannot manufacture. They were "de-vitaminized" because they are fatty acids. Fatty acids are a major component of fatswhich, like water, are needed by the body in large quantities and thus do not fit the definition of vitamins which are needed only in trace amounts.
• Herbalists and naturopathshave named various therapedic chemicals "vitamins", even though they are not, including Vitamin T, Vitamin U and Vitamin X.
• Some authorities say that Ubiquinone, also called Coenzyme Q₁₀, is a vitamin. Ubiquinone is manufactured in small amounts by the body, like Vitamin D.
• Pangamic acidVitamin B₁₅; the related substance dimethylglycineis quite wrongly referred to as Vitamin B₁₅ but also labled B₁₆.
• The toxins Laetrileand amygdaline are sometimes referred to as Vitamin B₁₇. Both pangamic acid and laetrile were first proposed as vitamins by Ernst T. Krebs; neither are recognized by the medical community as vitamins. B₁₇'s anticancer activities have been disproven by many experiments.
• Flavonoidsare sometimes called Vitamin P.
• Animal, bird, and bacterial growth factors have been designated vitamins such as para-aminobenzoic acid (PABA) which is the chicken feathering factor Vitamin B₁₀, the folacin (see folic acid) pteryl-heptaglutamic acid is the chicken growth factor Vitamin B₁₁ or Vitamin Bc-conjugate and orotic acid as Vitamin B₁₃ for rats.
• A few substances were once thought to be B-complex vitamins and are referred to as B-vitamins in older literature, including B₄ (adenine) and B₈ (adenylic acid), but are no longer recognized as such.
• Fringe doctors have labeled some analgesics and antibiotics as vitamins.

Colloquial usage of the term

• Vitamin A and Vitamin C are sometimes used as slang terms for alcoholic beveragesand caffeine, respectively.
• Vitamin G is sometimes used as slang for Guinness.
• Biotin is sometimes referred to as Vitamin H.
• Vitamin I is a colloquialism for ibuprofen.
• Vitamin J has been used to refer to Jägermeister, which is a herbal liquor exported from Germany.
• The sedative ketamineis often called Vitamin K when used as a recreational drug.
• Vitamin Love is mentioned in the Patti Pagesong, "I Don't Care if the Sun Don't Shine", referring to loveitself.
• Vitamin S is a slangfor steroids.
• Vitamin W is a colloquialism for water.
• Vitamin V is a colloquialism for Viagra, Vitamin Z for Zoloft, and Vitamin R for Ritalin, especially when implying that these drugs are overprescribed (or, as a hyperbole, taken as commonly as vitamins).
• Colloquially, the word vitamin is often used to refer to vitamin supplements, products, often in pill form, that contain one or more purified vitamins which are used to supplement the vitamin content of a diet.

Non-human vitamins

Different organisms need different trace organic substances. Most mammalsneed, with few exceptions, the same vitamins as humans. One notable exception is Vitamin D; most mammals can synthesize this. The less related a species is to mammals, the more different the organisms' requirements become. For example, some bacterianeed adenine. Pyrroloquinoline quinone(PQQ) found in yogurt was reported as a vitamin for mice in 2003. Housecats require the nutrient taurine; this makes it a vitamin for them, but not for humans as they can manufacture their own taurine.

See also

• nutrients
  • Dietary minerals
  • Essential amino acids
  • Nootropics (cognitive enhancers)
  • Nutraceuticals
• Illnesses related to poor nutrition
• Pharmacology
• Vitamin poisoning (overdose)

References

• 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.
• Funk, C. and H. E. Dubin. The Vitamines. Baltimore: Williams and Wilkins Company, 1922.
• The History of Vitamin Discovery. Retrieved 1 Feb 2005.
• Bellis, Mary. History of Vitamins. Retrieved 1 Feb 2005.
• Challem, Jack (1997). The Past, Present and Future of Vitamins. Retrieved 1 Feb 2005.
• Leonhardt, David (2004). Vitamin A - The Glow in the Dark Vitamin. Retrieved 1 Feb 2005.
• A Brief Update on Ubiquinone (Coenzyme Q10), Journal of Orthomolecular Medicine 2000; 15(2):63-68.

External links

• USDA RDA chart in PDF format
• The lab which discovered the enzyme associated with PQQ
• Health Canada Dietary Reference Intakes Reference Chart for Vitamins
• Article recording for the sensory impaired

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This article is licensed under the GNU Free Documentation License.
It uses material from the http://en.wikipedia.org/wiki/Vitamin Wikipedia article Vitamin.