How vitamins got their names ?

By 1915, Osborne and Mendel and also McCollum and
Davis had between them distinguished two types of
accessory factors based on their solubilities and called
them ‘fat-soluble A’ and ‘water-soluble B’. Fat-soluble
A was present in butterfat and egg yolk; a defi ciency
of this substance produced an infectious eye disease
(xerophthalmia) and growth retardation in young
rats. Water-soluble B was present in wheat germ and
milk powder; its defi ciency produced the avian form
of beriberi in pigeons. In 1920, the terminal ‘-e’ was
dropped from the word ‘vitamine’ and fat-soluble A
and water-soluble B were renamed vitamin A and
vitamin B, respectively. The anti-scurvy factor was
named vitamin C. For some time it was considered
probable that the anti-rickets factor might be identical
with vitamin A, since those foods which protected
against experimental rickets were generally the same
as those rich in vitamin A. Later, however, differences
in distribution and chemical properties were
established, and the anti-rickets factor was designated
vitamin D. In 1922 Evans and Bishop discovered an
anti-sterility factor necessary for successful reproduction
in the rat; this factor was later named vitamin E.
An anti-haemorrhagic factor for chicks reported in
1935 by Dam was later named vitamin K.
Vitamin B eventually proved to be a mixture of
compounds having different chemical and physiological
properties. This mixture is referred to today
as the ‘vitamin B complex’ in accordance with the
original nomenclature. The components of the vitamin
B complex were originally designated arbitrarily
as vitamins B1, B2, B3, B4, etc.
Gaps in the present alphabetical and numerical
designations can be explained by the fact that several
nutritional factors originally claimed to be vitamins
turned out not to be vitamins after all, or were identical
to another vitamin. Later, when the vitamins had
been isolated and chemically characterized, they
were given names according to the class of chemical
compounds to which they belong. The last vitamin to
be discovered was vitamin B12, which was isolated in
crystalline form from liver in 1948.