Vitamin B3 (Niacin): Health Benefits, Foods & Daily Amount

Updated in February 2024

Vitamin B3, also known as niacin, helps to regulate energy metabolism. It converts energy from carbohydrates, fats and proteins into energy to be used by cells.

Vitamin B3, which is found in the form of nicotinic acid or nicotinamide, also acts as an antioxidant, and participates in the production of hormones and in the repair of DNA.

Niacin can be transformed in the body by ingesting tryptophan, however, it is mainly obtained through the consumption of foods such as chicken, red meat, fish or avocado. It can also be consumed in the form of supplements.

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Health benefits

Vitamin B3 consumption is associated with the following health benefits:

  • Regulates energy metabolism, as it transforms the energy present in carbohydrates, proteins and fats into energy for the body's cells
  • Maintains cellular health, because it regulates processes such as cellular communication, DNA formation and repair
  • Strengthens the immune system, as it acts as an antioxidant and protects defense cells against damage from free radicals
  • Reduces LDL and triglyceride levels, as it prevents the oxidation of fat cells, which reduces the production of triglycerides and the production of fat in the liver;
  • Participates in the formation of cholesterol, thus helping in the production of hormones such as adrenaline and noradrenaline.

Furthermore, vitamin B3 could also help prevent cancer, due to its antioxidant action that helps fight free radicals. However, more studies are needed to confirm this benefit.

Foods rich in niacin

Vitamin B3, or niacin, is found in both animal sources of food (e.g. chicken, beef, eggs and fish) and plant-based sources (e.g. brown rice, whole wheat flour, nuts, beans, chickpeas, broccoli, avocado and tomato).

Tryptophan is also another source of vitamin B3, because this amino acid can be converted to nicotinamide in the liver. Some foods rich in tryptophan include eggs, tofu, almonds, bananas and cashews. Check-out a complete list of foods with tryptophan that you can add to your diet.

Recommended daily amount

The recommended daily amount of niacin varies according to age, sex and life stage. Recommended amounts are as follows:

Age / Sex

Recommended daily amount

0 to 6 months

2 mg

6 to 12 months

4 mg

1 to 3 years old

6 mg

4 to 8 years old

8 mg

9 to 13 years old

12 mg

Men/Boys over 14 years old

16 mg

Women/Girls over 14 years old

14 mg

For pregnant women, the recommendation is 18 mg of vitamin B3 per day. Women who are breastfeeding should consume 17 mg of vitamin B3 daily.

Normal levels & how to measure

Measuring vitamin B3 levels in the blood is a not reliable of actual values. Therefore, the assessment of vitamin B3 levels in the body is done through a urine test, which analyzes the urinary excretion dosage of N1-methyl-nicotinamide and methyl-pyridone-carboxamide.

Adults with normal levels of vitamon B3 in the body have excretion rates of more than 17.5 micromol/day of methyl-pyridone-carboxamide and N1-methyl-nicotinamide. Excretion rates between 5.8 and 17.5 micromol/day indicate a low level of vitamin B3. An adult with urinary excretion rates below 5.8 micromols/day is considered to have a vitamin B3 or niacin deficiency.

High vitamin B3 levels

Excess niacin only occurs with prolonged use and/or high doses of supplements. It can cause red spots, itching, burning and tingling sensations on the face, arms and chest, low blood pressure, nausea, dizziness, headache and stomach pain.

Furthermore, consumption of more than 1g of niacin per day can also cause glucose intolerance, insulin resistance, hepatitis and liver failure. Therefore, it is recommended to use this supplement only as prescribed by a doctor or registered dietitian.

Vitamin B3 deficiency

A vitamin B3 deficiency can occur mainly in people who do not consume a lot of vitamin B3 or tryptophan sources. It can also occur in people with alcoholism, as alcohol prevents the absorption of this nutrient and increases the elimination of niacin in the urine.

Additionally, people with inflammatory bowel disease, anorexia nervosa, liver cirrhosis, or AIDS may also experience niacin deficiency.

A vitamin b3 deficiency can cause pellagra, a serious disease that causes symptoms such as dark spots on the skin, diarrhea, neurological changes such as headache, mood changes and memory loss.