Vitamins are organic molecules that are required in the diet for normal
health and growth of anorganism. This need arises due to the inability
of cells to produce these compounds. The name 'vitamin' was originally
given to these accessory food factors because these were known to be
vital for life and were all believed to be amines. When it became clear
that some of them were not amines and did not even contain nitrogen,
Drummond suggested the modification that led to the term vitamin. Their
minute quantity requirement indicates a catalytic role in the cell. The
distinguishing feature of the vitamins is that they generally cannot be
synthesized by mammalian cells and, therefore, must be supplied in the
diet.