The yellow pigment carotene is apparently the plant source of the vitamin A of animal tissue. The suspicion of a relationship of yellow color in dietary substances, such as yellow corn, sweet potatoes and certain vegetables, was ventured by Steenbock and others several years ago. After a period of uncertainty and even denial, the identity seems no longer to be questionable. There was the demonstration that yellow corn furnished enough of the fat-soluble vitamin to allow growth at a normal rate in experimental animals, whereas the feeding of white corn under similar conditions resulted in nutritional failure. Continued confirmation of the ability of purified carotene to function as vitamin A is being reported from various laboratories.
The best information at present indicates that carotene and vitamin A are not identical, but rather that the pigment functions in the animal body as a precursor of the familiar vitamin. This would harmonize
CAROTENE AND VITAMIN A. JAMA. 1931;97(3):181. doi:10.1001/jama.1931.02730030031014