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Niacin Facts

What is Niacin?

Niacin is a water-soluble B vitamin, essential for energy metabolism in the cells, the proper functioning of the gastrointestinal and nervous systems, healthy skin, and the release of energy from carbohydrates, fats and protein.

Niacin requirements

The RDA for niacin (as NE) in healthy adults is 16 mg/day for males and 14 mg/day for females. The Upper Limit of Intake (UL) for niacin is 35 mg/day for adults. The requirements for niacin are expressed as Niacin Equivalents (NE), because the body can convert the amino acid, tryptophan, to niacin.

What happens when Niacin intake is too high?

The form of niacin produced in the body from tryptophan (niacinamide) cannot cause problematic side-effects, but excessive use of niacin supplements can produce flushing, itching, liver damage, high blood sugar, and gout. Side effects usually occur at doses of greater than 2 grams/day. High amounts of niacin are sometimes ordered by a doctor to help treat high cholesterol levels. In this case, the vitamin is acting as a drug. Supplemental niacin should be taken on a full stomach.

What happens when Niacin intake is too low?

Low intake of niacin is unlikely in healthy people eating a wide variety of food; however, symptoms of niacin deficiency can start with skin problems, muscle weakness, and indigestion, and can progress to a condition known as pellagra. Pellagra is a significant niacin deficiency which leads to the four ā€œDā€™sā€: diarrhea, dermatitis, dementia, and death. Alcoholics and other undernourished people are at risk of developing pellagra. Most people, however, eat enough protein-rich foods to prevent pellagra.

People who live in areas where maize (Indian corn) is the main food source are at risk of developing pellagra because maize is low in both niacin and tryptophan. The niacin in maize also cannot be absorbed in the intestine unless the maize is treated with alkali, like in the preparation of tortillas.

Which foods are high in Niacin?

Foods high in protein are highest in niacin. These foods include lean meat, liver, fish, poultry, eggs, legumes, peanut butter; also, enriched cereals.
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