The food we take into our bodies supplies us with many important substances such as proteins, fats, carbohydrates, water, and mineral substances. But these alone are not enough. In order to maintain life we need still other substances known as vitamins.

Vitamins are substances formed by plants or animals. They must be supplied to the body in minute quantities so that vital processes can continue undisturbed. When there is a lack of vitamins in our body, diseases will occur. For instance, lack of vitamin A affects our vision; lack of vitamin B produces a disease called beriberi, and so on.