What is vitamin B3? What is niacin?


MNT Knowledge Center

Vitamin B3, also known as Niacin, vitamin PP, and nicotinic acid, is one of eight B vitamins. Niacin helps the food we eat turn into energy – it also plays a role in maintaining our skin and nerves healthy.

Any niacin our body does not need is excreted in urine; it is not stored in the body, so we need to consume it daily.

Contents of this article:

    1. What is vitamin B3?


  • Recommended daily allowance



  • Food sources



  • Vitamin B3 deficiency


What is vitamin B3?

Vitamin B3 is a water-soluble vitamin – meaning that it dissolves in water – with pellagra-curative, antilipemic, and vasodilating properties, according to PubChem.1

The molecular formula of vitamin B3 is: C6H5NO2

The derivative of niacin is nicotinamide, which is used by the body to create the coenzymes nicotinamide adenine dinucleotide phosphate (NADP) and nicotinamide adenine dinucleotide (NAD) .2

NAD plays an important role in the catabolism of protein, carbohydrate, fat, and alcohol. NADP is involved in anabolism reactions such as cholesterol synthesis.3

Recommended daily allowance

According to the U.S. National Institutes of Health4, people should consume the following quantities of vitamin B3 per day:

  • Infants 0 to 6 months – 2 mg per day*
  • Babies 7 to 12 months – 4 mg per day*
  • Children 1 to 3 years – 6 mg per day
  • Children 4 to 8 years – 8 mg per day
  • Children 9 to 13 years – 12 mg per day
  • Boys and men aged at least 16 mg per day
  • Girls and women aged at least 14 mg per day.

*Adequate Intake (AI)

Pregnant and lactating females will require more and should check with their health care professional.

Nutritionists and dieticians say that those who eat a well balanced diet will consume adequate amounts of niacin.

Food sources

The following foods are known to be good sources of niacin:5

  • Anchovies
  • Beef
  • Bread (whole wheat)
  • Beans
  • Cheese
  • Cereals
  • Chicken
  • Eggs
  • Fish – tuna, salmon
  • Lamb
  • Leaf vegetables
  • Legumes
  • Liver, heart and kidney
  • Milk
  • Mushrooms
  • Nuts
  • Pasta (enriched)
  • Sunflower seeds
  • Yeast extract.

The Institute of Medicine says people should not consume more than 35 mg per day. Excessive intake can result in liver damage, niacin flush, and raised glucose levels among people with diabetes.

Vitamin B3 deficiency

Vitamin B3 deficiency can potentially lead to pellagra. Pellagra is known as the disease of the four “Ds” – diarrhea, dermatitis, dementia and death. Patients may also have glossitis (ulcerations inside the mouth), nausea, seizures, vomiting and ataxia (balance disorder).


Industrialized nations have virtually no cases of pellagra thanks to better diets and the addition of niacin to foods. According to a Morbidity and Mortality Weekly Report by the CDC6, Between 1906 and 1940 over 3 million US citizens got pellagra, of whom over 100,000 died.

In some poor countries today, pellagra continues being a public health problem. Corn and rice, which have low levels of vitamin B3, are primary sources of nutrition in some poor countries – those are the ones with the highest rates of pellagra, experts say.

In 1914, Dr. Joseph Goldberger was asked by the US Public Health Service to the South to investigate and deal with pellagra in the south of the country, where rates were much higher than the north.7

He inspected prisons, mental hospitals and orphanages and found that pellagra rates among the children, inmates and patients were considerably higher than rates among the staff. Goldberger concluded that Pellagra was not an infection but something else, probably something to do with diet.

When meat was added to the people’s diets, all the signs and symptoms of pellagra disappeared. Eight years after Goldberger died, scientists at the University of Wisconsin discovered the niacin connection (1937). As well as preventing pellagra, niacin can also cure it.

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