What did Joseph Goldberger do to provide evidence of the relationship between pellagra and nutrition?

Pellagra was long considered a contagious disease, but Joseph Goldberger set out to prove otherwise. In 1915, Goldberger was assigned by the U.S. Public Health Service to investigate an outbreak of pellagra in rural Mississippi. He soon suspected that the disease was related to diet and began conducting a series of experiments.

He and his colleagues lived with the same families who were affected by pellagra and ate exactly what they ate. Despite the fact that they came into close contact with people with pellagra, they did not develop the disease themselves because their diet was supplemented with fresh vegetables, milk, eggs, and meat. When pellagra-free volunteers ate the same diet as affected peoples, they also developed pellagra. This suggested that diet played a role in causinh pellagra, rather than contagion.

Goldberger concluded that pellagra was a disease caused by a deficiency of specific nutrients and, in particular, a lack of niacin. This discovery had a profound impact on public health, as it paved the way for the development of effective treatments and preventive measures for pellagra.