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A vitamin is an organic compound that cannot be synthesized (either at all or in sufficient quantities) by a given organism and must be taken (in trace quantities) with food for that organism's continued good health. The term vitamin is not used for inorganic trace nutritional requirements (these are dietary minerals) or for essential fatty acids or for essential amino acids.

The name was coined by the Polish biochemist Kazimierz Funk in 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.

Introduction

Vitamins were first recognised by the diseases that occur from a lack of certain foods; for example, the British Royal Navy's observation that limes were effective in preventing scurvy led to the discovery of vitamin C.

Vitamins can be divided in two groups by their solubility in water:

Water-soluble vitamins

• Ascorbic acid (vitamin C)
• Thiamine (vitamin B1)
• Riboflavin (vitamin B2)
• Niacin or nicotinic acid (vitamin B3) (also called vitamin P for pellagra prevention)
• Pantothenic acid (vitamin B5)
• Pyridoxine or pyridoxamine (vitamin B6)
• Cobalamin (vitamin B12)
• Biotin (vitamin H)
• Folic acid (vitamin M)
• Pyrroloquinoline quinone (PQQ)

Fat-soluble vitamins

• Retinol and derivatives (vitamin A)
• Calciferol (vitamin D)
• Tocopherol (vitamin E)
• Naphthoquinone and derivatives (vitamin K)

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. Unlike food, water, and—for aerobic organisms—air, an organism can survive for some time without vitamins, although prolonged vitamin deficit results in a disease state.

Vitamin deficiency diseases

Several diseases are caused by a lack of adequate vitamin intake. These can become severe, even life-threatening.

Some vitamin deficiency diseases include:

Other vitamin deficiencies are simply called after the name of the vitamin, such as vitamin K deficiency disease.

Is vitamin D a real vitamin?

Vitamin D is synthetized by human body, but not always in sufficient quantities. The level of synthesis depends on exposure to sunlight, so in winter and in polar areas there is a greater need to take it, whereas in summer and in equatorial areas it is less necessary. It is generally considered 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 fulfill the same functions in organisms (or are converted into the active form by the organism), so taking just one of the derivatives is sufficient for good health. The derivatives differ in chemical structure and level of activity.

Names

Some vitamin names have become obsolete:

• Vitamin B – actually a complex of several vitamins: B-number, H, and M.
• Vitamin G – another name for riboflavin (vitamin B2)

The usage of names in the format "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 by their symbolic names, and A and K don't even have proper chemical names (since they are mixtures of chemicals).

The names ascorbic acid and vitamin C are used with similar frequency.

Whatever Happened to Vitamin F?

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.

What is Vitamin S?

Although there was not originally a Vitamin S, the suggestion has been half-seriously made that salicylic acid may qualify for the criteria needed to be defined as a vitamin, and that in this case the designation "Vitamin S" could be used to describe it.

Non-human vitamins

Different organisms need different trace organic substances. The list of vitamins in this article refers to humans. Most mammals need, with few exceptions, the same vitamins (except that most species don't need ascorbic acid). The further we go from mammals, the more diverse organisms' requirements become. For example, some bacteria need adenine.

See pharmacology.

External links

• USDA RDA chart in PDF format
• April 24, 2003, Japanese Discover First New Vitamin in 55 Years Quote: "... The best source of PQQ discovered so far is "natto," a pungent Japanese dish of fermented soybeans. Other foods rich in the substance include parsley, green tea, green peppers, kiwi fruit and papaya. PQQ is not generally included in multi-vitamin tablets available on the market, the release said. ..."
• The lab which discovered the enzyme associated with PQQ
• April 24, 2003 By REUTERS: Japanese Discover First New Vitamin in 55 Years