Vitamin

From New World Encyclopedia
Revision as of 23:23, 3 April 2006 by Rick Swarts (talk | contribs) (Added article from Wikipedia)
(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)

Note: This is only a rough draft, with notes. Please do not edit this article until the final draft is complete — i.e., when this notice is removed. You may add comments on what you would like to see included in the discussion area. Rick Swarts 23:23, 3 April 2006 (UTC)

A vitamin is an organic molecule required by a living organism in minute amounts for proper health. An organism deprived of all sources of a particular vitamin will eventually suffer from disease symptoms specific to that vitamin.

Vitamins can be classified as either water soluble, which means they dissolve easily in water, or fat soluble, which means they are absorbed through the intestinal tract with 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 human body can derive from precursors include vitamin A, which can be produced from beta carotene; niacin from the amino acid tryptophan; and vitamin D through exposure of skin to ultraviolet light.

The term vitamin does not encompass other essential nutrients such 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 vitamine was coined by the Polish biochemist Casimir Funk in 1912. Vita in Latin is life and the -amine suffix is for amine; at the time it was thought that all vitamins were amines. This is now known to be incorrect.

History

The value of eating certain foods to maintain health was recognized long before vitamins were identified. The ancient Egyptians knew that feeding a patient liver would help cure night blindness, now known to be caused by a vitamin A deficiency. In 1747, the Scottish surgeon James Lind discovered that citrus foods helped prevent scurvy, a particularly deadly disease in which collagen is 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 Arctic expeditions in the 19th century, for example, it was widely believed that scurvy was prevented by good hygiene on board ship, regular exercise, and maintaining the morale of 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 Antarctic in the early 20th century, the prevailing medical theory was that scurvy was caused by "tainted" canned food.

In 1881, Russian surgeon Nikolai Lunin fed mice upon an artificial mixture of all the separate constituents of milk known 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 Fletcher discovered that eating unpolished rice instead of polished helped prevent the disease beriberi. The following year, Frederick Hopkins postulated that foods contained "accessory factors"—in addition to proteins, carbohydrates, fats, etc.—that are necessary to the human body. When Casimir Funk isolated 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 Drummond proposed that the final "e" be dropped, to deemphasize the "amine" reference, after the discovery that vitamin C had 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 oil was used to cure rickets in 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 steroid derivative. What we now call "vitamin A" was identified in fish oil because it was inactivated by ultraviolet light. 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).

Vitamin Name Chemical Name Solubility Deficiency Disease Overdose Estimated Average
Minimum Daily Requirement
(M,19-30)[2]
Vitamin A Retinol Fat Night-blindness, Keratomalacia 25,000 IUs 620μg
Vitamin B1 Thiamine Water Beriberi n/a 1mg
Vitamin B2 (G) Riboflavin Water Ariboflavinosis n/a 1.1mg
Vitamin B3 (PP) Niacin Water Pellagra 2,500 mg 12mg
Vitamin B5 Pantothenic acid Water Paresthesias n/a
Vitamin B6 Pyridoxine Water n/a 400 mg 1.1 mg
Vitamin B7 (H) Biotin Water n/a n/a 30 µg
Vitamin B9 (M) Folic acid Water [3] 1,000 µg 320 μg
Vitamin B12 Cyanocobalamin Water Pernicious anemia n/a 2 µg
Vitamin C[4] Ascorbic acid Water Scurvy n/a 75 mg
Vitamin D1-D4 Lamisterol, Ergocalciferol, Calciferol, Dihydrotachysterol, 7-dehydrositosterol Fat Rickets 50,000 IU 2 µg for all Vitamin D
Vitamin E Tocopherol Fat n/a 50,000 IU 12 mg
Vitamin K Naphthoquinone Fat n/a n/a 75 µg

^  Folic acid (Vitamin B9) deficiency in pregnant women is associated with birth defects, and has links to cancer as well.
^  Vitamin C is sometimes considered a macronutrient rather than a vitamin.

Some of the vitamins are known by other names in older literature. These names are written after the vitamins in brackets. Vitamin B2 is also referred to as Vitamin G. Vitamin B7, or biotin is 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 referred to as Folicin. Vitamin B3 is 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 nutrients that are not classified as vitamins include carnitine (meat,fish,dairy), 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 disease state, 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 acids that the body cannot manufacture. They were "de-vitaminized" because they are fatty acids. Fatty acids are a major component of fats which, 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 naturopaths have 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 acid Vitamin B15; the related substance dimethylglycine is quite wrongly referred to as Vitamin B15 but also labeled B16.
  • The toxins Laetrile and 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.
  • Flavonoids are 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 beverages and caffeine, respectively.
  • The sedative ketamine is often called Vitamin K when used as a recreational drug.
  • Vitamin Love is mentioned in the Patti Page song, "I Don't Care if the Sun Don't Shine", referring to love itself.
  • 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: being 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.
  • Vitamin G is used as slang for Guinness.
  • Vitamin J has been used to refer to Jägermeister, which is a herbal liquor exported from Germany.
  • Biotin is sometimes referred to as Vitamin H.
  • Vitamin I is sometimes used as a colloquialism for ibuprofen.
  • Vitamin S is slang for speed-amphetamins or steroids.
  • Vitamin W is sometimes used as a colloquialism for water.

Non-human vitamins

Different organisms need different trace organic substances. Most mammals need, with few exceptions, the same vitamins as humans. One notable exception is Vitamin C, which can be synthesized by all other mammals except other higher primates and guinea pigs. The less related a species is to mammals, the more different the organisms' requirements become. For example, some bacteria need adenine. Pyrroloquinoline quinone (PQQ) found in yogurt was reported as a vitamin for mice in 2003.

See also

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

References
ISBN links support NWE through referral fees

External links


Vitamins
All B vitamins | All D vitamins
Retinol (A) | Thiamine (B1) | Riboflavin (B2) | Niacin (B3) | Pantothenic acid (B5) | Pyridoxine (B6) | Biotin (B7) | Folic acid (B9) | Cyanocobalamin (B12) | Ascorbic acid (C) | Ergocalciferol (D2) | Cholecalciferol (D3) | Tocopherol (E) | Naphthoquinone (K)

bg:Витамин ca:Vitamina cs:Vitamín da:Vitamin de:Vitamine es:Vitamina eo:Vitamino fa:ویتامین fr:Vitamine ko:비타민 hy:ვიტამინ id:Vitamin is:Vítamín it:Vitamine he:ויטמין ka:ვიტამინ lb:Vitamin lt:Vitaminas hu:Vitamin mk:Витамин nl:Vitamine ja:ビタミン no:Vitamin nn:Vitamin pl:Witamina pt:Vitamina ro:Vitamină ru:Витамины simple:Vitamin sk:Vitamín sl:Vitamin fi:Vitamiini sv:Vitaminer ta:உயிர்ச்சத்து th:วิตามิน vi:Vitamin tr:Vitamin uk:Вітаміни zh:维生素

Credits

New World Encyclopedia writers and editors rewrote and completed the Wikipedia article in accordance with New World Encyclopedia standards. This article abides by terms of the Creative Commons CC-by-sa 3.0 License (CC-by-sa), which may be used and disseminated with proper attribution. Credit is due under the terms of this license that can reference both the New World Encyclopedia contributors and the selfless volunteer contributors of the Wikimedia Foundation. To cite this article click here for a list of acceptable citing formats.The history of earlier contributions by wikipedians is accessible to researchers here:

The history of this article since it was imported to New World Encyclopedia:

Note: Some restrictions may apply to use of individual images which are separately licensed.