Vitamins as a food supplement. Abstract image of assorted vitamin pills in a sandwich. This composition represents vitamin pills as a supple- ment to food. Vitamins are complex organic substances required in small amounts for the normal functioning, healthy growth and development of the body. Most vitamins cannot be made in the body and so are essential components of a healthy diet. There are 13 vitamins: A,C,D,E,K and the eight B group vitamins. A lack of sufficient quantities of vitamins can lead to vitamin deficiency diseases.