Vitamins are substances of mainly vegetable origin which provide an essential part of our food and nourishment. Lack of vitamins leads to ill health. The Australian aborigines have for many centuries treated certain eye diseases by applying the liver of a fish similar to the tuna to the affected part of the eye. Scientists discovered that the liver of the fish was rich in vitamin A which is excellent for eyesight.

A common disease in Asia is beriberi which causes paralysis and swelling throughout the body. In 1882 a doctor in the Japanese navy discovered that beriberi could be cured by eating barley instead of rice. The doctor had noticed that many Japanese sailors ate a lot of polished rice and they contracted a disease similar to beriberi. These sailors were the victims of a lack of vitamins found on the outer husk of the grain of rice.

In 1897, Dr. Eijkman, working in a prison in Java, found that chickens fed on polished rice contracted a disease that resembled beriberi. The chickens became better if their diet was changed to unpolished rice. Eijkman concluded that the outer part of a grain of rice contained a vitamin that fought beriberi. This was vitamin B. Its use on the victim cured him of the beriberi.

The children who lived in damp and unhealthy slums of London often suffered from rickets which weakens the bones and distorts their shape. In 1650, Dr. Glisson found that cod liver oil benefited these children. The oil is rich in vitamin D.

In 1936, two American scientists raised a sow on an artificial diet containing all the vitamins (A, B. C, D) which were discovered up to that point. The scientists also put another sow on the same diet but gave it a large quantity of lettuce to eat. The first sow proved unable to bear even a single piglet against the second which produced a horde. The scientists concluded that the lettuce contained a hitherto unknown vitamin which they named as vitamin E. This is also known as the fertility vitamin.