ABSTRACT
Niacin is used in a generic application to nicotinic acid and nicotinamide. Niacin deficiency is usually associated with diarrhea, dermatitis, dementia, and finally death. Niacin participates in more than 200 reactions that are involved in the metabolism of fatty acids, amino acids, and carbohydrates. Much of the niacin in certain foods such as corn is in a bound form frequently unavailable to the human. Nicotinic acid is used in large doses to treat hyperlipedemia. Nicotinic acid, but not nicotinamide, will produce flushing as a consequence of histamine release. The most commonly used procedure to assess niacin nutritional status has been the measurement of the niacin metabolites, N’-methylnicotinamide and N’-methyl-2-pyridone-5-carboxamide, in the urine. Metabolically, niacin serves as a component of the cosubstrates nicotinamide adenine dinucleotide and nicotinamide adenine dinucleotide phosphate. The high-performance liquid chromatography procedure of Carter is simple, sensitive, specific, and accurate for measuring N’-methyl-2-pyridone-5-carboxamide and N’-methylnicotinamide in urine specimens.
