Pellagra is a vitamin deficiency disease most frequently caused by a chronic lack of niacin (vitamin B3 or synonym: vitamin PP (from: Pellagra Preventing factor)) in the diet. It can be caused by decreased intake of niacin or tryptophan, and possibly by excessive intake of leucine. It may also result from alterations in protein metabolism in disorders such as carcinoid syndrome or Hartnup disease. A deficiency of the amino acid lysine can lead to a deficiency of niacin, as well.
The connection between maize and pellagra was first described by Casal in Spain in 1735.When it became an endemic disease in northern Italy, Francesco Frapoli of Milan named it 'pelle agra" (pelle, skin; agra, sour). Clinically, the disease is identified by the three Ds-dermatitis, diarrhoea and dementia-and if untreated, pellagra typically leads to death in four or five years.
Mexico despite widespread consumption of maize. The reason appeared to lay in the different way in which the grain was prepared in Mexico. The people of the Aztec and Mayan civilisations softened the corn to make it edible with an alkaline solution-limewater. This process liberated the bound niacin (also known as niacytin) and the important amino acid tryptophan, from which niacin can be formed, making both "bioavailable" for digestion.
