Though he identified that a missing nutritional element was responsible for pellagra, he did not discover the specific vitamin responsible. In 1937, Conrad Elvehjem, a biochemistry professor at the University of Wisconsin-Madison, showed that the vitamin niacin cured pellagra (manifested as black tongue) in dogs. Later studies by Dr. Tom Spies, Marion Blankenhorn, and Clark Cooper established that niacin also cured pellagra in humans, for which Time Magazine dubbed them its 1938 Men of the Year in comprehensive science.Research conducted between 1900 and 1950 found the number of cases of women with pellagra was consistently double the number of cases of affected men. This is thought to be due to the inhibitory effect of estrogen on the conversion of the amino acid tryptophan to niacin. Some researchers of the time gave a few explanations regarding the difference.Gillman and Gillman related skeletal tissue and pellagra in their research in South Africans. They provide some of the best evidence for skeletal manifestations of pellagra and the reaction of bone in malnutrition. They claimed radiological studies of adult pellagrins demonstrated marked osteoporosis. A negative mineral balance in pellagrins was noted, which indicated active mobilization and excretion of endogenous mineral substances, and undoubtedly impacted the turnover of bone. Extensive dental caries were present in over half of pellagra patients. In most cases, caries were associated with "severe gingival retraction, sepsis, exposure of cementum, and loosening of teeth". Etymology
The word pellagra comes from the Lombard words "pell" (skin) and "agra" (fem. sour).
2 oz or 60 grams) of fresh mushrooms treated with ultraviolet light have increased vitamin D content to levels up to 80 micrograms or 3200 IU if exposed to just five minutes of UV light after being harvested.Button mushrooms with enhanced vitamin D2 content produced this way functions similarly to a vitamin D2 supplement; both effectively improves vitamin D status. Vitamin D2 from UV-irradiated yeast baked into bread or mushrooms is bioavailable and increases blood levels of 25(OH)D.

Names
Viosterol, the name given to early preparations of irradiated ergosterol, is essentially synonymous with ergocalciferol. However, currently, Viosterol is also the brand name for cholecalciferol (vitamin D3) in some countries.Ergocalciferol is manufactured and marketed under various names, including Deltalin (Eli Lilly and Company), Drisdol (Sanofi-Synthelabo) and Calcidol (Patrin Pharma). References
External links
"Ergocalciferol". Drug Information Portal. U.S. National Library of Medicine. NIST Chemistry WebBook page for ergocalciferol