Translations:Vitamin D/105/en

History

Main article: Vitamin § History

Vitamin D was discovered in 1922 following on from previous research. American researchers Elmer McCollum and Marguerite Davis in 1914 discovered a substance in cod liver oil which later was called "vitamin A". British doctor Edward Mellanby noticed dogs that were fed cod liver oil did not develop rickets and concluded vitamin A, or a closely associated factor, could prevent the disease. In 1922, Elmer McCollum tested modified cod liver oil in which the vitamin A had been destroyed. The modified oil cured the sick dogs, so McCollum concluded the factor in cod liver oil which cured rickets was distinct from vitamin A. He called it vitamin D because he thought it was the fourth vitamin to be named. It was not initially realized that vitamin D can be synthesized by humans (in the skin) through exposure to UV light, and therefore is technically not a vitamin, but rather can be considered to be a hormone.