Function: Niacin, the precursor of NAD and NADP. is essential for normal fuel metabolism as well as for the synthesis or removal of numerous compounds. Food sources: Good sources include enriched grain products, yeast, seeds, legumes, dairy, meat, poultry, fish, green leafy vegetables, and coffee.
Requirements: Dietary intakes are expressed as milligram niacin equivalents (NE). which correspond to I mg pure niacin or 60 mg tryptophan (the alternate precursor of NAD and NADP). Men should gel Uung. women 14mg NT. per day. Dieiary requirements are slightly higher during pregnancy and lactation.
Deficiency: Late symptoms of severe deficiency (pellagra) include fatigue, headache, apathy, depression, memory loss, dementia, pigmented skin rash after sun exposure, bright red tongue, vomiting, diarrhea or constipation.
Excessive intake. Flushing (burning and itching of face, arms and chest) and stomach irritation arc the main side effects of moderately high supplemental niacin intake (more than 35 mg/d). Liver damage that may culminate in irreversible liver failure is a risk associated with long-term use of very high doses (3000 and more mg dl as a cholesterol-lowering drug. Such high doses must never be used without close monitoring of liver function. High intakes of nicotinic acid may interfere with the effects of sulfinpyrazone (Anturane).
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