Niacin is one of the eight water-soluble B vitamins. The others include vitamin B1 (thiamin), B2 (riboflavin), B5 (pantothenic acid), B6 (pyridoxine), B7 (biotin), B9 (folate), and B12 (cobalamin).
As a water-soluble vitamin, unused vitamin B3 is regularly excreted. This is unlike the fat-soluble vitamins (A, D, E, and K), which accumulate and are stored in the liver and fatty tissues.
The daily removal of vitamin B3 means it’s important to make sure you’re regularly replenishing stores to prevent insufficiency and deficiency.
Perhaps the most important role of vitamin B3, and B vitamins in general, is the conversion of food into energy. Niacin is also needed for cellular health, metabolism, proper nervous system function, and antioxidant protection.1,2
Heart Health
Niacin may offer some heart health benefits. Many people are prescribed niacin by their doctor as a way to help improve blood fat profiles. The clinically used form is called nicotinic acid, which provides a significantly higher dose than the RDA for niacin. Nicotinic acid is generally a 1,000-2,000 mg dose of vitamin B3 taken daily.
Specifically, some studies have found that this can help reduce triglycerides and raise levels of HDL, the “good” cholesterol, but it’s not a perfect science.
A 2017 Cochrane review including 23 randomized controlled trials on nicotinic acid for preventing heart attacks, strokes, and related deaths concluded that these supplements may lower blood fats, but didn’t actually reduce overall death or event rate.3
Plus, very high doses of niacin don’t come without potential risks, such as liver damage, gastrointestinal issues, and glucose intolerance. One very common side effect of a large dose of niacin is skin flushing, caused by dilation of small blood vessels in your skin.4
Overall, it’s important to remember that this isn’t a quick fix for heart health. Other factors, like diet and exercise, are also crucial.
Brain Health
Severe vitamin B3 deficiency is associated with memory loss and dementia. Adequate niacin is thought to help protect brain cells from injury and stress-related deterioration.
For instance, a 6-month long 2003 prospective study including dietary questioning data from over 3700 elderly adults found that the highest intake of niacin was associated with the most protective effect against Alzheimer’s and cognitive decline.5
Additionally, the 2017 Coronary Artery Risk Development in Young Adults (CARDIA) study, which measured B vitamin intake from food and supplements among over 31000 adults for up to 25 years, found that higher intake of niacin, in particular, was associated with better cognitive function scores at mid-life.6
While more research is needed, it appears that getting enough niacin is important for brain health.
Pellagra
Vitamin B3 is also a treatment for pellagra, a condition that can result from niacin deficiency. Pellagra symptoms can present as severe skin inflammation, mouth sores, diarrhea, and even dementia.7
Primary pellagra results from a diet lacking niacin and tryptophan. Secondary pellagra develops because niacin is not sufficiently used by the body, often because of conditions like alcoholism or GI disorders.
The recommended daily amounts of niacin are measured in milligrams (mg) of niacin equivalents, abbreviated as NE, for everyone over 6 months old.8 This is because, in addition to ingesting vitamin B3 directly, your liver can also produce it from the essential amino acid tryptophan.
Hence, the amounts of niacin you make as a byproduct of eating other foods in your diet may be substantially different from someone else. The NE is designed to represent both the niacin you eat as well as the niacin you produce from tryptophan. One NE is equal to 1 milligram of niacin or 60 mg of tryptophan.9 The RDAs for niacin are as follows:2
|
Population |
RDA |
|
0-6 months |
2 mg |
|
7-12 months |
4 mg NE |
|
1-3 years |
6 mg NE |
|
4-8 years |
8 mg NE |
|
9-13 years |
12 mg NE |
|
14-18 years |
14 mg NE (females); 16 mg NE (males) |
|
19+ years |
14 mg NE (females); 16 mg NE (males) |
|
Pregnancy |
18 mg NE |
|
Lactation |
17 mg NE |
Source: National Institutes of Health, 2019. Accessed January 12, 2022. https://ods.od.nih.gov/pdf/factsheets/Niacin-Consumer.pdf
It is possible to get too much niacin, though the concern is related to its use in supplemental form and not from food. The tolerable upper limit (UL) for niacin is 35 mg for adults.8
And on the other hand, vitamin B3 deficiency is very rare in western cultures as it can be found in so many places.9
Still, there are a few groups that may be at an increased risk for niacin deficiency. These include under- or malnourished individuals, such as those with anorexia, alcoholism, liver cirrhosis, or inflammatory bowel disease.2
Foods That Are Packed With Vitamin B3
Vitamin B3 is found in just about every multivitamin with minerals supplement, as well as B complex supplements, and on its own as a niacin supplement. It’s also found in a wide variety of foods.
A few places you can find niacin in your diet include:
- Liver
- Turkey
- Tuna
- Chicken
- Salmon
- Peanuts
- Mushrooms
- Avocado
- Brown Rice
- Whole Wheat
- Potatoes
- Peas
- Fortified and enriched grains and cereals
Since you also make niacin from tryptophan, it’s also helpful to know what foods contain this amino acid. Good sources of tryptophan include:
- Turkey
- Chicken
- Pork
- Red meat
- Fish
- Tofu
- Eggs
- Oatmeal
- Nuts and seeds
- Beans and legumes
- Dairy products
Vitamin B3 vs. Other B Vitamins
All of the B vitamins are essential for health, and they work synergistically to make sure a wide range of cellular and metabolic processes are carried out correctly in the body.
Niacin may help protect heart health by managing the amounts of fats circulating in your bloodstream. However, this generally requires very high doses of supplemental niacin and should only be used under medical supervision. It may also help prevent cognitive decline by protecting your brain cells.
Most people will have no trouble finding enough vitamin B3 in their diet, through foods like poultry, beef, fish, nuts, seeds, legumes, and whole grains. If you take a multivitamin or B complex, vitamin B3 will be present there as well.
Over the years, there have been some suggestions that B Vitamins can contribute to weight gain. We address that topic head-on in this article.
