Ironically, although pellagra is usually typical of a diet based on corn (maize), where maize is a traditional dish, it is prepared with lye to release its dietary niacin. However, as corn spread from the Americas to become a staple of diets everywhere, the general methods of preparation meant the maize was niacin deficient. Because pellagra was common in children as well as adults, it was often mistaken for intellectual disability. Many children living in institutions developed the disease.