Pellagra is a disease caused by a niacin (B-vitamin) deficiency, lack of tryptophan (an amino acid) in the diet, or a failure to absorb these nutrients. Pellagra is common in parts of the world where people have a lot of corn in their diet. In the U.S., it was almost epidemic among the Southern poor who ate a diet high in corn, molasses, and fat-back.
Pellagra was defined as a specific disease around the turn of the 20th century. Doctors diagnosed it by classic symptoms like dermatitis, diarrhea, and…dementia which frequently took the form of stupor and melancholy. For years, pellagra was thought to cause insanity, and many victims were sent to asylums as a result. Some patients may have recovered once their diets became less corn-based, but diets were often poor in asylums.
During the winter of 1913-1914, Surgeon General Rupert Blue appointed an epidemiologist named John Goldberger to conduct pellagra studies. Goldberger thought there might be a nutritional component, since staff at insane asylums rarely developed pellagra, while patients did. (Staff ate more nutritious food, in general). He discovered that in one Georgia asylum, nearly 8% of patients developed pellagra after they were admitted.
Dr. Goldberger is credited with discovering the nutritional basis of pellagra, but he was not able to name the specific component (niacin) responsible. In 1937, a chemist named Conrad A. Elvehjem discovered that nicotinic acid could cure black tongue (a symptom of pellagra) in dogs; after that treatment for pellagra became readily available.