Vitamins were first recognised by the diseases that occurred from the lack of certain foods; the British Navy recognised that a constituent of limes prevented scurvy (one possible result of not having enough vitamin C over an extended period of time), so limes were added to the diet of sailors. Vitamin D prevents rickets, and so forth.
Vitamins can be divided in two groups by their solubility in water, as follows.
Water-soluble vitamins:
Fat-soluble vitamins:
Unlike food, water, and--for aerobic organisms--air, an organism can survive quite some time without vitamins, although prolonged 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?.
Several diseases are caused by lack of adequate vitamin intake. These can become severe, even life-threatening.
Deficiency in:
Vitamin A causes night blindness Vitamin B1 causes beriberi? Vitamin B2 causes ariboflavinosis? Vitamin B12 causes [pernicious anemia]? Niacin causes pellagra? Vitamin C causes scurvy Vitamin D causes rickets
Other vitamin deficiencies are simply called after the name of the vitamin, like vitamin K deficiency disease.
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.
The 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.
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 (but the majority of them 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.