Vanishing Nutrients

Rice: Processing to get white rice removes 90% of natural thiamine, 85% of natural niacin, 60% of natural iron (NIH, 2020). The resulting Thiamin/Vitamin B1 deficiency caused a rash of severe disease called beriberi in Asia, 1880s–1920s.
Corn: Degermination cuts 60% fiber, 50% magnesium (USDA, 2019). Pellagra (from Vitamin B3/Niacin deficiency) marked by dermatitis (skin rash), diarrhea, dementia, death killed 100,000+ in U.S., 1900–1940.
Flour: Refined flour loses 80% fiber, 70% iron (USDA, 2020). Enrichment, to try to put back some nutrients, began in 1940s.