Vitamin B3 (Niacin)

By Barbara E. Amsler, MD

Niacin deficiency causes a disease known as pellagra, which was prevalent in Spain and Italy during the eighteenth century. This disease, characterized by dementia, dermatitis, diarrhea and death, spawned a search for the cause. Niacin was first isolated in tobacco when nicotine was oxidized. The chemical was called “nicotinic acid vitamin” which was later shortened to “niacin”. It is also known as nicotinamide, although it is not chemically related to nicotine.

Niacin and its derivatives are essential as coenzymes in over 200 chemical reactions in the body. They assist in the repair of DNA (our genetic information) and the conversion of energy from fats, cholesterol, proteins and carbohydrates (sugars and starches). Vitamin B3 aids in the synthesis of estrogen, progesterone, testosterone and the adrenal hormones, as well as, the production of red blood cells. Niacin has been shown to reduce high cholesterol, depression, schizophrenia, anxiety, indigestion, hypoglycemia and tooth and gum problems.

Vitamin B3 is the most stable of the B vitamins and stands up to heat, light, air, acid and alkali conditions. It is absorbed well from both the stomach and small intestine. A small amount can be stored in the liver but the majority of excess niacin is excreted by the kidney. About 50% of our body’s niacin is made from the amino acid, tryptophan but this requires iron, vitamins B1, B2, B6 and C. Deficiencies in these other nutrients may result in reduced niacin levels.

Niacin deficiency is common in those with corn-based diets (China, Africa and India), alcoholics and people with carcinoid or congenital abnormalities of tryptophan absorption (Hartnup’s disease). In the early stages of pellagra, there are symptoms of decreased appetite, weakness, irritability, abdominal pain and vomiting. The tongue is sore and beefy red. The skin develops sun sensitivity becoming red, rough, dry and scaly with increased pigmentation.

As the deficiency progresses the rapidly reproducing cells, of the intestinal tract, are affected. This results in diarrhea, indigestion, tender gums, decreased acid production by the stomach and impaired absorption and energy conversion from foods.

The nervous system is also affected. The symptoms begin with headaches, irritability, insomnia and progress to tremors, confusion, depression and anxiety. The disease finally gives way to psychosis, dementia, seizures and death.

Niacin deficiency can be determined by measuring urinary excretion of either 2-methyl nicotinamide or 2-pyridone. Blood levels of niacin or tryptophan may not be reliable indicators.

The deficiency state can be rapidly improved by using niacin supplementation (in the range of 100 mg – 200 mg three times daily for 5 days). Proteins rich in tryptophan and B complex vitamins are added to continue conversion to niacin.

For cholesterol problems, higher doses of niacin (1000 mg – 2000 mg daily) can be used. Toxicity to niacin is rare but has been reported in doses of 3000 – 9000 mg daily. Jaundice (yellow coloring of the skin) and increases in liver enzymes, in the blood, are signs of liver toxicity. There have also been reports of increased muscle breakdown (rhabdomyolysis) in those concurrently taking high doses of niacin and statins (Lipitor, Crestor, Zocor, etc).

Natural sources of niacin include Brewer’s yeast, liver, poultry, wheat bran, peanuts, wild rice, fish (especially swordfish, halibut, tuna, salmon), whole grains, beans, peas, almonds, sesame seeds, sunflower seeds, avocados, prunes, dates, figs, milk and eggs.

The recommended daily intake of niacin is 14 mg for women and 16 mg for men but higher doses can be taken. Flushing is the most common side effect of larger doses. Those under stress, physically active, consuming high sugar diets or recovering from an illness or injury need more niacin (25 mg daily). Women who are pregnant or breast feeding as well as children/teens experiencing a growth spurt should also take more niacin (17-18 mg daily and 12-14 mg daily respectively).

Healthy Habits for Vitamin B3 (niacin) intake:

1) Daily intakes of niacin and the amino acid, tryptophan, are required for optimal energy and health. Remember, the conversion of tryptophan to niacin requires other B vitamins, iron and vitamin C, so supplement these also.

2) Women taking birth control pills should take extra niacin, as studies have shown they have decreased absorption of several B vitamins, including B3.

3) People with bipolar disorders (depression and manic episodes) may benefit from the addition of niacin and tryptophan.

4) Larger doses of niacin have been shown to increase HDL (good cholesterol) and decrease LDL (bad cholesterol). The flushing associated with these higher doses (1000-2000 mg) can be blocked by taking an aspirin about 30 minutes before the niacin dose.

5) Higher doses of niacin may increase blood sugar levels, by affecting insulin activity. Therefore, blood sugar should be monitored closely in diabetics taking niacin supplementation to control their cholesterol.

6) Those taking statins and niacin should notify their doctor immediately if they develop unusual muscle pains, as this may be a sign of rhabdomyolysis.


karinVitamin B3 (Niacin)

Comments 2

  1. Gareth Sitz

    Thanks for another informative article. It certainly makes me want to remember to take my multivitamin every day.:) You are very thorough in your description, and I was particularly interested in sections that apply to my specific health issues.

  2. Martha Schooley

    bravo on another thorough article about benefits of eating the right foods;
    Is there a one page chart which summarizes these important vitamins and which foods to obtain the natural sources of these vitamins?

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