The prevention and conquest of scurvy, beri-beri, and pellagra.

I have described how many years of research were needed to overcome three nutritional diseases that occurred throughout the world. When human beings migrated from tropical and subtropical regions to the temperate zone, they lost their year-round supplies of vitamin C, and scurvy began to occur. The emergence of beri-beri had a mechanical basis; the introduction of milling, which prevented the rancidity of rice and wheat, also removed the essential vitamin B1. The circumstance leading to the third deficiency disease was reliance on maize, without supplementing it with "protective" foods, such as meat, milk, and vegetables. Under conditions of poverty, the protective foods became expensive, and pellagra appeared. Synthetic chemistry, together with improvements in the diet and in education, largely overcame scurvy, beri-beri, and pellagra, but deficiencies of vitamins A, C, and folic acid still occur widely in economically disadvantaged populations, and this is a challenge to those who wish to improve public health. The brilliant prophesies of Casimir Funk, made in 1912, were fulfilled within 25 years. Today, his word "vitamin" is universally familiar. The account of the discovery, identification and synthesis of the vitamins is the story of how human beings have overcome nutritional deficiencies that were imposed by cultural and economic disadvantages or just plain ignorance. These discoveries were a triumph of science and technology. Much of the research depended on the use of experimental animals: guinea-pigs, rats, dogs, monkeys, and chickens. Vitamins are now added to the diets of both animals and human beings.