Write a note on vitamins.

(N/A) Vitamins are organic compounds required in the diet in small amounts to perform specific biological functions for the normal maintenance of optimum growth and health of an organism.
Most vitamins cannot be synthesized in our body,but plants can synthesize almost all of them,making them essential food factors.
However,bacteria in the gut produce some of the vitamins required by us.
Vitamins are difficult to define based on structure.
Vitamins are designated by alphabets such as $A$,$B$,$C$,$D$,etc.
Some are further named as subgroups,e.g.,$B_{1}$,$B_{2}$,$B_{6}$,$B_{12}$,etc.
Excess of vitamins is harmful,and vitamin pills should not be consumed without medical advice.
The term "Vitamine" was coined from "vital + amine" because early identified compounds contained amino groups.
Later research showed that most do not contain amino groups,so the letter '$e$' was dropped,and the term "vitamin" is used today.