Niacin, also known as vitamin B3 or niacinamide, plays many vital roles in the body. It is essential for the nervous system, digestive system, heart health and the health of the skin.

A deficiency in vitamin B3 can lead to a condition known as pellagra, which causes rashes, headaches, memory loss, fatigue, vomiting, and diarrhea.

Natural sources of Niacin could be chicken, liver, peanuts, green peas, etc. However, taking vitamin B3 supplements in high doses can also cause side effects.

In this article, you will learn all about niacin, including its different sources, its benefits, side effects of high doses and the typical signs of deficiency.

What is niacin?

Niacin, also known as vitamin B3, is one of the eight B vitamins. This water-soluble vitamin is found in numerous foods like fish, chicken, red meats, nuts, whole grains, and dried beans.

The body also makes small amounts of niacin from the amino acid tryptophan.

Vitamin B3 is found in two main chemical forms, both of which are found in foods as well as supplements. 

Nicotinic acid: The supplements of nicotinic acid are used for the treatment of lipid disorders and cardiovascular disease (1).

Niacinamide: This form of vitamin B3 helps treat psoriasis and reduces the risk of non-melanoma cancer (2, 3). Niacin helps activate over 200 enzymes which help regulate the breakdown of carbohydrates, fats, and proteins.

Niacin is a component of the coenzymes nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP), which are involved in 50 chemical reactions in the body.

Niacin also acts as an antioxidant and plays a role in cell signaling and making and repairing DNA.

Daily intake

The amount of niacin you need depends on your age and gender. Here is the reference daily intake for niacin (4) –

Adequate intake for infants

  • 0 to 6 months: 2 mg/day
  • 7 to 12 months: 4 mg/day

RDI for children

  • 1 to 3 years: 6 mg/day
  • 4 to 8 years: 8 mg/day
  • 9 to 13 years: 12 mg/day

RDI for adolescents and adults

  • 14 years and older (men): 16 mg/day
  • 14 years and older (women): 14 mg/day
  • Pregnant women: 18 mg/day
  • Breastfeeding women: 17 mg/day

Health benefits of niacin

1. Improves cholesterol levels

Niacin has been used for the treatment for high cholesterol for a long time. It lowers the level of LDL cholesterol by 5 to 25 percent and raises the HDL levels by 15 to 35 percent. It also reduces triglyceride levels by 20 to 50 percent (5).

According to studies, niacin is an important therapeutic option for reducing the risk of cardiovascular disease in patients with mixed dyslipidemia who, in addition to high LDL-C, have elevated TGs and low HDL-C (6).

Doctors often prescribe niacin along with statins for cholesterol control along with medicines like Crestor, Lipitor, and Lescol.

2. Helps prevent and reduce the risk of heart disease

Niacin helps prevent oxidative stress and inflammation which can lead to atherosclerosis. Atherosclerosis is the hardening of arteries that can lead to coronary heart disease.

Vitamin B3 reduces the levels of low-density lipoproteins in the blood which is one of the significant risk factors for heart disease.

According to a 2015 study, 30 men with high lipoprotein were given 500 mg of extended-release niacin for 24 weeks.  The high dose of ER niacin declined the elevated levels of lipoprotein(a) in these men (7).

Recent studies have also shown that not only is niacin safe to use in persons with diabetes but that its combination with statins is also safe and effective (8).

3. Help treat Type 1 diabetes

You develop Type 1 diabetes when your immune system destroys cells in your pancreas called beta cells. These are the cells that make insulin.

Vitamin B3 in the form of niacinamide improves the function of beta cells and improves diabetes (9). It also reduces the risk of type 1 diabetes in children that are at a higher risk (10).

Other than controlling the levels of blood sugar, niacin also helps to lower the risk of high blood pressure and heart disease, which are common in people with diabetes (11).

When it comes to type 2 diabetes, niacin may not have a similar result. While it does lower cholesterol which is common in people with type 2 diabetes, it can also increase blood sugar levels.

So if you have Type 2 diabetes, check with your doctor before taking any niacin supplements.

4. Boosts brain health

The brain needs niacin in the form of coenzymes NAD and NAPD to function correctly. Brain fog and psychiatric symptoms are associated with niacin deficiency (12).

Niacin is also used to treating and preventing schizophrenia and hallucinations (13). Many studies have shown that niacin is effective in treating depression, bipolar disorder and other psychiatric disorders (14, 15).

Some studies have also shown that dietary niacin can protect against Alzheimer’s disease and age-related cognitive decline (16).

5. Protects and improves skin health

Niacin, when used orally or as a lotion, protects skin cells against sun damage (17).

Niacin also helps in treating inflammation of the skin and acne. Whether it is a topical application or oral supplements, niacin in the form of nicotinamide is effective in treating acne (18).

Vitamin B 3 is also useful in treating skin cancers. According to a 2015 trial, oral nicotinamide was safe and effective in reducing the rates of melanoma skin cancers (19).

6. Help reduce symptoms of arthritis

Niacin also helps reduce the symptoms of osteoarthritis including joint pain and inflammation. During a 1996 study, 72 patients with osteoarthritis were treated with niacinamide and a placebo for 12 weeks.

The results showed that niacinamide improved the global impact of osteoarthritis, improved joint flexibility, lowered inflammation, and allowed for a reduction in standard anti-inflammatory medication when compared to the placebo (20).

Niacin is generally prescribed in high doses for the treatment of osteoarthritis and joint and bone pain thanks to its anti-inflammatory properties. Reducing inflammation helps rebuild joint cartilage, which improves mobility and strength.

7. Treats pellagra

Severe deficiency of niacin can lead to a condition called pellagra (21). Its symptoms include digestive problems, weak muscles, inflammation, and skin irritation.

This condition is mostly seen in poverty-stricken areas and is rare in industrialized countries. It may occur with other diseases like alcoholism, anorexia or Hartnup disease.

Taking high levels of vitamin B3 in the form of nicotinamide is the primary treatment for pellagra.

8. Prevents congenital disabilities

Nicotinamide adenine dinucleotide (NAD) molecules are essential for energy storage and DNA synthesis in cells. Vitamin B3 helps prevent NAD defects, so increasing B3 levels in pregnant women can help reduce the rate of congenital disabilities.

According to one article published in The New England Journal of Medicine when NAD molecule synthesis is disrupted, it can cause a deficiency of NAD and malformations in humans and mice.

Niacin supplementation during gestation prevented malformation in mice (22). More human studies should be done to confirm its effects.

9. Prevents impotence

Niacin is a vasodilator, and it helps improve blood flow in the body. In addition to factors like stress and fatigue, erectile dysfunction can also be caused by inadequate circulation and low blood flow.

During to a 2011 study by the Department of Urology, The Chinese University of Hong Kong, 160 patients with erectile dysfunction were given 1,500 mg oral niacin or a placebo for 12 weeks.

The results showed that niacin along could improve erectile function in patients suffering from moderate to severe ED and dyslipidemia (23).

Best food sources of niacin

Niacin is found in many foods including nuts, legumes, meats, poultry, and fish. Many forms of traditional medicine like Ayurvedic Medicine and Traditional Chinese Medicine use niacin-rich foods as a treatment for fatigue, strengthening of the spleen, improving liver health and nourishing the blood.

You can easily meet your daily requirement for niacin by eating healthy food. It is also much safer than taking niacin supplements which may cause side effects in some people.

Here’s are some of the best niacin-rich foods to add to your diet (24) –

  1. Chicken (1 cup): 19.2 mg (96 % DV)
  2. Liver (1 slice): 11.9 mg (60% DV)
  3. Tuna (3 ounces): 11.3 mg (56% DV)
  4. Turkey (1 cup): 9.6 mg (48 % DV)
  5. Salmon (3 ounces): 6.8 mg (34 % DV)
  6. Sardines (1 can): 4.8 mg (24 % DV)
  7. Grass-fed beef (3 ounces): 4.4 mg (22 % DV)
  8. Sunflower seeds (1 cup): 3.8 mg (19 % DV)
  9. Peanuts (1 ounce): 3.8 mg (19% DV)
  10. Green Peas (1 cup): 3.2 mg (16 % DV)

Side effects of niacin

Foods rich in niacin are considered safe. Niacin supplements, on the other hand, can be hard to tolerate for some people. In some people, high doses of supplements, taken via prescription can cause:

  • Rapid heartbeat
  • Reddening and flushing of the face
  • Nausea and vomiting
  • Itching
  • Abdominal pain
  • Diarrhea
  • Gout
  • Liver damage
  • Diabetes

If you have liver disease, peptic ulcers or severely low blood pressure, you should avoid taking niacin. High doses of niacin (2,000 to 6,000 mg ) can lead to liver damage, can activate your ulcer and even lead to hypotension.

If you have type 2 diabetes, niacin can increase your blood sugar levels. It can also increase the levels of uric acid in the blood and lead to gout.

Niacin is not recommended for pregnant women with high cholesterol.

Niacin interactions

1. Blood pressure medications

If you are taking blood pressure medications or herbs, taking niacin can have an additive effect and may cause low blood pressure.

2. Diabetes medications

Niacin can interfere with blood glucose control, so you may have to adjust your blood pressure medication if you are taking niacin.

3. Anticoagulants

These drugs reduce blood clotting and taking niacin along with them may increase the risk of bleeding.

4. Allopurinol

Since niacin can increase the level of uric acid in the blood, you may have to take more of this gout medicine if you are taking niacin.

5. Alcohol

Alcohol consumption along with niacin can increase your risk of liver damage. It can cause side effects like flushing and itching.

Final thoughts

Niacin is a water-soluble B vitamin that is used by the body to turn food into energy. It helps lower cholesterol, boosts brain health, reduces the risk of heart disease, improves skin and prevents congenital disabilities.

It is made by the body in small amounts and is also available in food like meats, fish, legumes, and seeds.

Niacin can also have side effects in some people when taken in high doses. Some of the common side effects include flushing and redness of the skin, nausea, itching, abdominal pain, and rapid heartbeat.

Niacin, also known as vitamin B3 or niacinamide, plays many vital roles in the body. It is essential for the nervous system, digestive system, etc.