pellagra

a DEFICIENCY DISEASE caused by a lack of nicotinic acid, part of the VITAMIN B complex. It occurs when the diet is based on maize (rather than wheat) with an associated lack of firstclass PROTEIN (meat and milk). The reason is that although maize contains nicotinic acid. it is in an unusable form and also it does not contain the AMINO ACID tryptophan, which the body can use to produce nicotinic acid. The symptoms are DERMATITIS , DIARRHOEA and DEPRESSION .