“Goldberger’s research proved that pellagra was a dietary disease, and that it could be reversed or avoided by consuming fresh meats, milk, eggs, and other nutrient-rich foods. The national Public Health Service instructed physicians to prescribe a nutrient-rich diet for Southerners at the highest risk of suffering from pellagra. Unfortunately, in the poorest pockets of the rural South, doctors bristled at taking orders from the East Coast medical establishment. Many ignored the new recommendations.”
https://www.southernfoodways.org/malnourished-cultural-ignorance-paved-the-way-for-pellagra/

Sounds familiar.