Pellagra, a disease caused by a lack of vitamin B-3 (niacin) in the diet, became epidemic among the poor in the southern United States in the late 19th and early 20th centuries. […]
Pellagra, a disease caused by a lack of vitamin B-3 (niacin) in the diet, became epidemic among the poor in the southern United States in the late 19th and early 20th centuries. […]