Vitamin B3 is a water-soluble vitamin that cannot be stored in body fat. It has two active components, nicotinic acid (niacin) and nicotinamide (niacinamide). This vitamin plays a role in over 200 enzymatic reactions.
The body can synthesize vitamin B3 in small amounts, provided it has sufficient stores of magnesium, vitamins B6 and B2, and tryptophan. The latter is an essential amino acid (part of a protein)—that is, it is not produced by the body and must be obtained from food sources.
NOTE: like many other members of the vitamin B family, vitamin B3 supplements are better absorbed when taken with food.
What does vitamin B3 do?
It plays a role in:
Some people need greater amounts of niacin, especially those afflicted with Hartnup disease (a hereditary disorder associated with impaired absorption of certain amino acids), cirrhosis of the liver, carcinoid syndrome, and malabsorption syndrome. Individuals who are undergoing hemodialysis or peritoneal dialysis (two purification techniques that use an artificial filter [dialyzer] or natural filter [the peritoneum], respectively, when the kidneys can no longer purify the blood) or receiving extended treatment for tuberculosis are also likely to require greater amounts of vitamin B3, as are women who are pregnant with multiples or nursing more than one infant.
Vitamin B3 requirements are expressed in niacin equivalents (NE).
Recommended Dietary Allowances for Niacin:
|Age Group||Quantity (niacin equivalents in mg)*|
|Infants||0 to 6 months||2mg**|
|7 to 12 months||4mg**|
|Children||1 to 3 years||6mg|
|4 to 8 years||8mg|
|Preteens||9 to 13 years||12mg|
|Men||14 years and up||16mg|
|Women||14 years and up||14mg|
|Pregnant women|| ||18mg|
|Nursing mothers|| ||17mg|
Source: www.passeportsante.net; Institute of Medicine, Food and Nutrition Board, Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline 2000.
This data reflects a consensus between Canadian and U.S authorities.
*Niacin amounts are expressed in “niacin equivalents” (NE): 1 mg NE = 60 mg of tryptophan = 1 mg of niacin.
**Lacking sufficient scientific evidence, authorities have established adequate intake (AI) amounts rather than recommended dietary allowances (RDAs) for this age group. Adequate niacin intake is based on observed average intakes in North American babies in good health.
Foods that are rich in vitamin B3 (niacin) include meat, liver, poultry, fish, enriched and wholegrain breads and baked goods, as well as enriched ready-to-eat cereals.
Food Sources for Vitamin B3 (Niacin):
|Foods||Portion Sizes||Vitamin B3 (niacin)|
|Sautéed or braised beef, lamb, or veal liver||100g (3½oz)||17-22mg|
|Roasted chicken (white meat, with or without skin)||100g (3½oz)||15-20mg|
|Dried and salted Atlantic cod||100g (3½oz)||19mg|
|Sautéed milk-fed veal cutlet||100g (3½oz)||19mg|
|Poached salmon||100g (3½oz)||18mg|
|Canned tuna||100g (3½oz)||16-18mg|
|Baked or grilled yellowfin tuna or swordfish||100g (3½oz)||17-18mg|
|Sautéed or braised veal leg, loin, or shank||100g (3½oz)||16-17mg|
|Smoked sturgeon||100g (3½oz)||17mg|
|Grilled domestic duck (without skin)||100g (3½oz)||17mg|
|Baked bluefin tuna, Spanish (striped) mackerel, king mackerel, salmon||100g (3½oz)||14-16mg|
|Baked shad||100g (3½oz)||11mg|
|Grilled Spanish mackerel||100g (3½oz)||11mg|
|Roasted Canada goose thigh, with skin||100g (3½oz)||10mg|
|Braised or roasted rabbit||100g (3½oz)||7-8mg|
|Dry- or oil-roasted peanuts||60ml (1/4 tasse)||6-7mg|
|All-bran breakfast cereals||30g (1oz)||6mg|
|Grilled pork, assorted cuts||100g (3½oz)||5mg|
|Grilled haddock||100g (3½oz)||4mg|
|Raw or steamed Pacific oysters||100g (3½oz) (2 à 4 moyennes)||2-4mg|
Source: www.passeportsante.net; Health Canada, Canadian Nutrient File, versions 2001b and 2005; United States Department of Agriculture (USDA), National Nutrient Database for Standard Reference.
Vitamin B3 (niacin) deficiency is rare in developed nations, where protein-rich foods are common. A deficiency may be due to a lack of vitamin B6, which the body requires in order to convert tryptophan to niacin. Alcoholics may also suffer from vitamin B3 deficiencies because alcohol inhibits the absorption of this vitamin at the intestinal level.
Signs of vitamin B3 deficiency:
Pellagra is a disease resulting from severe niacin deficiency. It is characterized specifically by the following clinical signs and symptoms:
Large doses of vitamin B3 should be taken for therapeutic purposes only under medical supervision. Blood tests must be administered regularly to assess the patient’s liver function, in view of the many adverse reactions reported and the numerous medical interactions that are possible.
Signs of excess vitamin B3:
Natural health products or vitamin supplements:
It is theoretically possible that high doses of niacin, which lower cholesterol rates, may exacerbate the effects of plant components purported to do the same, such as:
Vitamin B3 should never be self-prescribed, as adverse reactions occur frequently and are potentially dangerous.
Vitamin B3, Niacin, Nicotinic acid, Nicotinamide, Vitamin PP