User:Dyuku/Discovery of vitamin D

Discovery of vitamin D
In the 17th century, Dr. Daniel Whistler (1645) and Professor Francis Glisson (1650) for the first time described rickets (vitamin D-deficiency).

In 1919-1920, Sir Edward Mellanby conducted experiments with dogs raised in the absence of sunlight. By altering their diet, he established unequivocally that rickets was linked with a diet deficiency. He also identified cod liver oil as an excellent antirachitic agent.

In 1923, Goldblatt and Soames further contributed to vitamin D studies. They established that when 7-dehydrocholesterol (a precursor of vitamin D in the skin) is irradiated with light, a form of a fat-soluble vitamin is produced. Hess and Weinstock further substantiated that "light equals vitamin D".

Professor A. Windaus, at the University of Göttingen in Germany, received the Nobel Prize in Chemistry in 1928, because of his work on the constitution of sterols and their connection with vitamins. In 1930s, he clarified further the chemical structures of the vitamins D.

Vitamin D2 was chemically characterized in 1932. And it was only in 1936 that the chemical structure of vitamin D3 was established; it resulted from the ultraviolet irradiation of 7-dehydrocholesterol.