Pellagra is a vitamin deficiency disease most frequently caused by a chronic lack of niacin in the diet. It can be caused by decreased intake of niacin.> Second, it may result from deficiency of tryptophan, an essential amino acid found in meat, poultry, fish, eggs, and peanuts that the body converts into niacin.> Third, it may be caused by excess leucine, as it inhibits quinolinate phosphoribosyl transferase (QPRT) and inhibits the format on of Niacin or Nicotinic acid to Nicotinamide mononucleotide (NMN) causing pellegra like symptoms to occur.">