What is pollegra?

What can you do to prevent pollegra?

I think you are referring to the defficiency disease called "Pellegra". It is caused by a chronic lack of niacin (vitamin B3) or its precursur tryptophan in the diet. It is characterized by dermatitis (skin rash), diarrhea, and mental disturbance, and is often linked to overdependence on corn as a staple. The wikipedia says is it is common in Africa, Indonesia, and China, but is rare in Western societies. In affluent societies the majority of patients with clinical pellegra are poor, homeless, alcohol-dependent, or psychiatric patients who refuse food. The best food sources of B3 are peanuts, brewer's yeast, fish, and meat. Some B3 is also found in whole grains.