Niacin (Vitamin B3)

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General Description:

  • water-soluble
  • partly supplied by the amino acid tryptophan, which is converted to niacin by the body
  • ”niacin” is really a generic term referring to several substances.
  • only two of these substances are important: nicotinic acid and niacinamide or nicotinamide, both of which can perform the traditional functions of niacin


  • niacin teams up with other substances in the body to form compounds that play a key role in the metabolism of carbohydrates, fats and proteins
  • functions as a part of two enzymes, nicotinamide adenine dinucleotide (NAD), and with an additional phosphate as NADP, which work in the glycogen energy cycle, the oxidation of fatty acids for energy, and in tissue respiration
  • has been used for certain blood fat disorders that increase the chance of developing heart disease
  • shows promise in new treatments for psoriasis
  • only nicotinic acid combats high blood fats and dilates blood vessels
  • softens skin
  • for almost a quarter of a century, heart experts have been using nicotinic acid to treat high blood fat levels
  • important for proper circulation and for a healthy nervous system
  • maintains normal function of the GI tract
  • may prevent migraine headaches


  • RDA is 19 mg.
  • a dose greater than 30 mg. causes vascular dilation with flushing, burning, and itching, the ”niacin flush”
  • no other nutrient deficiency disease claimed nearly as many American lives
  • nicknamed the ”plague of corn” the disease is called pellagra
  • the plague came to an end with the discovery that it was not caused by a germ, but rather a diet deficient in niacin
  • however, before pellagra occurs, B2, B6, and the amino acid tryptophan are also likely to be deficient, in addition to B3
  • some foods contain niacin in a form the body does not absorb (eg. corn)
  • therefore, pellagra occurs most commonly where corn and other grains are the basis of the diet
  • tryptophan, an amino acid, can be converted to niacin in the body.
  • niacin deficiency still does occur from time to time and most commonly the victims are alcoholics or those who have a poor diet
  • other possible causes include: chronic diarrhea, malabsorption diseases, cancer, prolonged fever, deficiency of vitamin B6 (impairs the body’s ability to convert tryptophan to niacin)
  • mild deficiency may cause: diarrhea, anxiety, depression, irritability, coated tongue, canker sores, nervousness, skin lesions, forgetfulness, insomnia, chronic headaches, digestive disorders, and anemia
  • first signs of deficiency usually show in the skin: ulcers, sores, and areas that appear sunburnt
  • more advanced symptoms: hallucinations, delerium, confusion, depression, mental dullness, disorientation and mental disease, pellagra, neurasthenia, and ultimately coma and death

Interactions and Toxicity:

  • toxicity is low up to 1000 mg./day
  • mega-doses (3-10 g.) cause glycogen to be used more quickly and also block the use of fatty acids as fuel
  • liver seems sensitive to excessive niacin and one symptom of objection is jaundice
  • if jaundice is not present at high doses of niacin it does not mean that all is well with the liver
  • toxicity seems to develop more quickly on time-released forms
  • chances are good for a full recovery from liver damage due to nicotinic acid
  • abnormal glucose tolerance has been found in both diabetic and normal patients taking high doses of nicotinic acid
  • blood levels of uric acid may also increase on large doses of nicotinic acid (Gout!)
  • hypothyroidism may also occur
  • nicotinic acid may enhance the pressure-lowering effects of some hgh blood pressure drugs
  • those with abnormal liver function, duodenal ulcers or active peptic ulcers, severe low blood pressure, hemorrhaging, or bleeding of the arteries should consider niacin off-limits
  • diabetics and those with gout, allergies (release of histamine) and pregnant women should take caution


  • brewer’s yeast, torula yeast, wheat germ, rice bran and rice polishings, nuts, sunflower seeds, peanuts, whole wheat products, brown rice, and green vegetables

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