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# Vitamin

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A vitamin is a organic compound that cannot be synthesized (at all or in quantities that fulfill all needs) by a given organism and must be taken (in trace quantities) with food for that organism's continued good health.

Vitamins were first recognised by the deseases that occurred from the lack of certain foods, the British Navy recognised that a constituant in limes prevented skurvy, so limes were added to the diet of sailors, which are a good source of vitamin C. Vitamin D prevents rickets, and so forth.

Vitamins can be divided in two groups by their solubility in water, as follows.

Water-soluble vitamins:

- Ascorbic Acid (Vitamin C)
- Thiamin? (Vitamin B1)
- Riboflavin? (Vitamin B2)
- Nicotinamide? (Vitamin B3) - amide of Niacin?, not true vitamin
- Niacin? (nicotinic acid, Vitamin B5)
- [Vitamin B6]? (pyridoxine)
- [Vitamin B12]? (cobalamin)
- Biotin? (Vitamin H)
- [Folic Acid]? (Vitamin M)

Fat-soluble vitamins:

- [Vitamin A]? (retinol and derivates)
- [Vitamin D]? (calciferol)- see below
- [Vitamin E]? (tocopherol)
- [Vitamin K]? (naphthoquinone and derivatives)

Unlike food, water, and--for aerobic organisms--air, an organism can survive quite some time without vitamins, although prolongued vitamin deficit results in a disease state. Organic vitamins are contrasted with other trace nutritional requirements that are inorganic in nature, referred to as minerals?.

### Is [Vitamin D]? a real vitamin ?

Vitamin D is synthetized by human body, but in quantities that are not always sufficient. Level of synthesis depends on sun activity, so in winter and in polar areas it's more like a vitamin, and in summer and in equatorial areas it's less like a vitamin. So it's usually treated as a vitamin, but one that isn't required in some areas, and seasons.

### Vitamins A and K

Neither [vitamin A]? nor [vitamin K]? is a single chemical substance, but all derivatives fulfil the same function in organism, so taking just one of derivatives is required for good health. Derivatives differ only by level of activity.

### Names

Some obsolete vitamin names:

- Vitamin B - actually complex of a few vitamins: B-number, H and M.
- Vitamin G - another name for Riboflavin (Vitamin B2)

Usage of names 'Vitamin <letter>' and 'Vitamin <letter><number>' is diminishing. This is especially true for vitamins H, M, B1, B2, B3 and B5, which are usually called by their proper chemical names.
On the other hand, vitamins D and E are still usually called with their symbolic names, and A and K don't even have proper chemical names.
Names Ascorbic Acid and Vitamin C are used with similar frequency.

It's very probable that in some distant future, all vitamins will be named with proper chemical names. We can see this evolution in case of Ascorbic Acid nowadays.

### Non-human vitamins

Different organisms need different trace organic substances. List of vitamins in this article refers to humans.
Most of Mammals? need, with a little exceptions, the same vitamins. For example Rat?s don't need Ascorbic Acid.

Further we go from Mammals?, the more diverse organism's requirements become. For example some Bacteria needs Adenine?.

/Talk

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Last edited August 16, 2001 7:38 pm (diff)
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