Niacin – Vitamin B3

Niacin – vitamin B3, is a water-soluble B vitamin found naturally in some foods, added to foods, and sold as a supplement. It comes third in the list of vitamin B complexes. The two most common forms of niacin in food and supplements are nicotinic acid and nicotinamide. The body can also convert tryptophan—an amino acid—to nicotinamide. Niacin is a water-soluble vitamin. Hence, an excess amount of this vitamin is easily excreted through urine. It works in the body as a coenzyme, with more than 400 enzymes dependent on it for various reactions. Niacin helps to convert nutrients into energy, create cholesterol and fats, create and repair DNA, and exert antioxidant effects.

The function of vitamin B3

  • It works in good blood circulation, normal functioning of the brain, and boosting memory. Hence, it enhances mental health.
  • Niacin increases high-density lipoprotein (HDL) cholesterol — the “good” cholesterol that helps remove low-density lipoprotein (LDL), the “bad” cholesterol, from your bloodstream.
  • It helps you to maintain a healthy digestive system and skin.
  • Vitamin B3 also helps in releasing energy from foods that we intake.

Deficiency of vitamin B3

  • It leads to pellagra, a condition that causes a dark
  • bright redness of the tongue
  • constipation/diarrhea
  • Depression
  • Headache
  • Fatigue
  • Memory loss
  • Hallucinations

Sources of niacin

  • Red meat: beef, beef liver, pork
  • Poultry
  • Fish
  • Brown rice
  • Fortified cereals and breads
  • Nuts, seeds
  • Legumes
  • Bananas 

Niacin is measured in milligrams (mg) of niacin equivalents (NE). One NE equals 1 milligram of niacin or 60 mg of tryptophan. The Recommended Dietary Allowance (RDA) for adults 19+ years is 16 mg NE for men, 14 mg NE for women, 18 mg NE for pregnant women, and 17 mg NE for lactating women.


Toxicity can occur from the long-term use of high-dose supplements. A reddened skin flush with itchiness or tingling on the face, arms, and chest is a common sign. Flushing occurs mainly when taking high-dosage supplements in the form of nicotinic acid, rather than nicotinamide.

  • Dizziness
  • Low blood pressure
  • Fatigue
  • Headache
  • Upset stomach
  • Nausea
  • Blurred vision
  • Impaired glucose tolerance and inflammation of liver in severe cases (at very high doses of 3,000-9,000 mg daily for several months/years)

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