Niacin - Vitamin B3

Thiamin, riboflavin, niacin, vitamin B6, pantothenic acid, biotin, folic acid, vitamin B12 and vitamin C are referred to as the water-soluble vitamins. Solubility in water is one of the only characteristics that they share. Because they are water soluble, these vitamins tend to be absorbed by simple diffusion when ingested in large amounts and by carrier – mediated processes when ingested in smaller amounts. They are distributed in the aqueous phases of the cell. Most are not stored in appreciable amounts, making their regular consumption a necessity.

Niacin is a water-soluble vitamin that helps your body produce energy from foods and participates in a variety of biochemical reactions in the body. Among the B group vitamins, niacin is unique in that the body can synthesize niacin from the amino acid tryptophan. This is not to say that your body doesn’t utilize the niacin that you consume from foods. It just meets its niacin requirement from both.

Niacin is also involved in controlling blood sugar levels, keeping skin healthy and maintaining the proper functioning of the nervous and digestive systems. 

Dietary reference intakes of Niacin

Infants 2 –4 mg/day

Children 6 – 8 mg/day

Adolescents 12 - 16 mg/day

Adults 14 - 16 mg/day

Pregnant 17 - 18 mg/day

Breastfeeding 17 - 18 mg/day 

Niacin content of selected foods

Ready to eat cereals, 1 cup (26.43 mg)

Chicken, ½ breast (14.73 mg)

Tuna, canned in water, 3 oz (11.29 mg)

Rice, white, 1 cup (7.75 mg)

Mushrooms, cooked, 1 cup (6.96 mg)

Beef, ground regular, cooked 3 oz (4.55 mg)

Ham, canned, 3 oz (4.28 mg)

Peanuts, dry, roasted, 1 oz (3.83 mg)

Bagel, plain, enriched, 1 medium bagel (4.1 mg)

Egg noodles, 1 cup (3.32 mg) 

Symptoms of Niacin deficiency

Muscular weakness

Anorexia

Indigestion

Skin eruptions

Pellagra (dermatitis, dementia, diarrhea; tremors; sore tongue)

Confusion

Disorientation

Neuritis 

Signs of Niacin toxicity

Flushing

High doses of niacin can also be toxic to the liver