[History of vitamins].

The history of the discovery of vitamins was initiated by the observation that beriberi is caused by qualitatively poor nutrition rather than by microorganisms. An early theory suggested the formation of toxins by improper cooking, preservation, or storage; however, research soon took another turn. Feeding experiments with standardized food pointed at the existence of 'accessory factors', present in food in small amounts. These factors seemed to be essential for the maintenance of metabolic processes, yet could not be synthesized by the organism. This was the initial spark for a worldwide research boom. The period from 1912 to 1948 saw the isolation and identification of individual factors belonging to a variety of chemical classes collectively labeled as 'vitamins'.