Vitamins
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 word vitamin was coined by the Polish biochemist Casimir 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.
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).
Some of the vitamins are known by other names in older literature. 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
-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.
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