Niacin, commonly known as vitamin B3, is a vital water-soluble vitamin that plays a crucial role in maintaining overall health. It’s naturally present in a variety of foods, added to certain food products, and also available as a dietary supplement. The primary forms of niacin found in food and supplements are nicotinic acid and nicotinamide. Interestingly, our bodies can also produce nicotinamide from tryptophan, an amino acid. Being water-soluble, any excess niacin that the body doesn’t utilize is efficiently removed through urine.
Vitamin B3 acts as a coenzyme, essential for the function of over 400 enzymes in the body. These enzymes are critical for numerous processes, including converting nutrients into usable energy, synthesizing cholesterol and fats, DNA creation and repair, and providing antioxidant protection. [1,2] Incorporating B3 Foods into your diet is therefore essential for these bodily functions.
Diverse array of b3 foods, showcasing niacin-rich sources such as legumes, nuts, seeds, carrots, chicken, avocado, eggs, grains, and broccoli.
Daily Recommended Intake of Vitamin B3 (Niacin)
Understanding the recommended daily intake of niacin is crucial for ensuring adequate consumption of b3 foods. Niacin levels are measured in milligrams (mg) of niacin equivalents (NE), where 1 NE is equivalent to 1 mg of niacin or 60 mg of tryptophan.
- Recommended Dietary Allowance (RDA): For adults aged 19 and above, the RDA is 16 mg NE for men, 14 mg NE for women, 18 mg NE for pregnant women, and 17 mg NE for lactating women.
- Tolerable Upper Intake Level (UL): The UL represents the maximum daily intake unlikely to cause adverse health effects. For all adults aged 19+, the UL for niacin is 35 mg. It’s important to note that while b3 foods are beneficial, excessive intake from supplements can lead to negative effects.
The Health Benefits of Niacin from B3 Foods
Niacin, obtained through b3 foods, plays a significant role in various aspects of health, particularly in cardiovascular and cognitive functions.
Cardiovascular Health and Niacin
Nicotinic acid, a form of niacin, has been used for decades to manage dyslipidemia, a condition characterized by imbalanced cholesterol and triglyceride levels, which is a major risk factor for cardiovascular diseases (CVD) like coronary artery disease, heart attacks, and strokes. Dyslipidemia is marked by high total and LDL (“bad”) cholesterol, low HDL (“good”) cholesterol, and elevated triglycerides.
While high-dose nicotinic acid supplements (1,000-2,000 mg daily) have shown potential in improving cholesterol profiles by increasing HDL and lowering LDL and triglycerides, they often come with unpleasant side effects such as skin flushing and gastrointestinal issues, leading to poor patient adherence. Furthermore, clinical trials have not consistently demonstrated that nicotinic acid supplementation reduces cardiovascular events or mortality related to CVD.
- Recent large-scale clinical trials have contradicted earlier findings regarding niacin therapy and CVD outcomes. [3,4] These randomized, placebo-controlled trials, spanning up to 4 years, investigated high doses of niacin supplements (1,500-2,000 mg daily), both as a standalone treatment and in combination with statins. Both trials concluded that niacin supplementation did not provide significant cardiovascular benefits. The niacin-statin combination trial failed to show a reduction in strokes, heart attacks, or CVD-related deaths, despite improvements in HDL cholesterol and triglyceride levels. [3] Similarly, the niacin-only supplement trial found no reduction in CVD events and, alarmingly, reported a higher incidence of adverse reactions, including type 2 diabetes, gastrointestinal bleeding, ulcers, and diarrhea, compared to the placebo group. [4]
- A comprehensive Cochrane review analyzing 23 randomized controlled trials on nicotinic acid supplements for CVD prevention corroborated these findings. It concluded that nicotinic acid supplements did not reduce overall mortality, CVD-related deaths, heart attacks, or strokes and were associated with negative side effects. [5]
- These and similar cardiovascular outcome trials prompted the U.S. Food and Drug Administration (FDA) to revise its stance, stating that “scientific evidence no longer supports the conclusion that a drug-induced reduction in triglyceride levels and/or increase in HDL-cholesterol levels in statin-treated patients results in a reduction in the risk of cardiovascular events.” [6] Consequently, the FDA deemed that the benefits of extended-release niacin tablets and fenofibric acid capsules taken with statins no longer outweighed the risks and should not be recommended.
It’s important to emphasize that obtaining niacin from b3 foods as part of a balanced diet is a more natural and potentially safer approach to supporting cardiovascular health compared to high-dose supplementation.
Cognitive Function and Niacin-Rich Foods
Severe niacin deficiency has been linked to cognitive decline, including memory loss and dementia. Niacin is believed to have neuroprotective properties, safeguarding brain cells from stress and damage. However, the impact of minor variations in dietary niacin intake on brain function remains an area of ongoing research. Consuming b3 foods may contribute to maintaining cognitive health.
- A large prospective study following 3,718 men and women aged 65 and older for 6 years assessed dietary intake and cognitive function. [7] The study found a protective effect against Alzheimer’s disease and cognitive decline in participants with the highest niacin intake compared to those with the lowest intake.
- The Coronary Artery Risk Development in Young Adults (CARDIA) study tracked 3,136 men and women aged 18-30 for up to 25 years. [8] This study evaluated B vitamin intake, including niacin, from diet and supplements, and cognitive function. Higher intake of B vitamins, particularly niacin, throughout young adulthood was associated with better cognitive function scores in midlife. However, cognitive function was only evaluated at the study’s conclusion, limiting the understanding of cognitive changes over time.
Research in this area is still evolving, with ongoing clinical trials aimed at further elucidating niacin’s effects on brain health. [9] Including b3 foods in your diet may be a proactive step in supporting long-term cognitive well-being.
Top Food Sources of B3 (Niacin Foods)
Niacin deficiency is uncommon because niacin is widely available in a variety of foods, both from animal and plant sources. Prioritizing b3 foods in your diet ensures adequate niacin intake.
- Meat: Red meat like beef and pork, particularly beef liver, are excellent sources of niacin.
- Poultry: Chicken and turkey are also good sources of vitamin B3.
- Fish: Various types of fish are rich in niacin.
- Grains: Brown rice and fortified cereals and breads contribute to niacin intake.
- Nuts and Seeds: Incorporating nuts and seeds into your diet provides a good source of niacin.
- Legumes: Legumes like beans and lentils are valuable plant-based b3 foods.
- Fruits: Bananas are among the few fruits that contain niacin.
An assortment of b3 foods, highlighting diverse dietary sources of niacin.
Niacin Supplements: When Are They Necessary?
Niacin is available as a dietary supplement, typically in the form of nicotinic acid or nicotinamide. Supplement dosages often exceed the RDA significantly, potentially causing flushing, a harmless but uncomfortable side effect. Prescription niacin supplements, used to treat high cholesterol, usually contain extended-release nicotinic acid for slower absorption and reduced flushing. Due to the high doses often required (up to 2,000 mg daily), prescription niacin supplements should only be used under medical supervision. For general health and niacin intake, focusing on b3 foods is generally recommended.
Recognizing Niacin Deficiency and Toxicity
Niacin Deficiency
Niacin deficiency is rare in developed countries due to its widespread availability in food and fortification of food products. Severe deficiency leads to pellagra, characterized by a dark, scaly rash on sun-exposed skin, a bright red tongue, and gastrointestinal issues like constipation or diarrhea. Other signs of severe deficiency include:
- Depression
- Headache
- Fatigue
- Memory loss
- Hallucinations
Groups at Risk of Niacin Deficiency:
- Limited Diets: Individuals with restricted food choices due to poverty or illness are at higher risk. Populations relying heavily on corn or maize as a staple food may also be at risk, as these are low in absorbable niacin and tryptophan.
- Chronic Alcoholism: Excessive alcohol consumption impairs the absorption of various nutrients, including water-soluble B vitamins like niacin.
- Carcinoid Syndrome: This condition, involving slow-growing cancer cells in the gut, can divert tryptophan metabolism away from niacin production, increasing deficiency risk.
Niacin Toxicity
Niacin toxicity from food sources is rare. It primarily occurs with long-term, high-dose supplement use. Skin flushing with itching or tingling is a common early sign, particularly with nicotinic acid supplements. High doses can also elevate uric acid levels, increasing gout risk. Other toxicity symptoms include:
- Dizziness
- Low blood pressure
- Fatigue
- Headache
- Upset stomach
- Nausea
- Blurred vision
- In severe cases (very high doses of 3,000-9,000 mg daily over months/years), impaired glucose tolerance and liver inflammation may occur. [1]
Fun Facts About Niacin and B3 Foods
- Many B vitamins, including niacin, are often associated with energy boosting. While niacin is crucial for energy metabolism, excessive supplementation beyond RDA levels does not provide extra energy. A balanced diet rich in b3 foods is sufficient for niacin’s energy-related benefits.
- Corn is naturally rich in niacin, but its bioavailability is limited. Nixtamalization, a traditional corn treatment process using calcium hydroxide, makes the niacin absorbable.
Related Resources
B Vitamins
Vitamins and Minerals
References
[1] National Institutes of Health. Niacin. Fact Sheet for Health Professionals. https://ods.od.nih.gov/factsheets/Niacin-HealthProfessional/
[2] Linus Pauling Institute. Niacin. Micronutrient Information Center. https://lpi.oregonstate.edu/mic/vitamins/niacin
[3] The AIM-HIGH Investigators. Niacin in Patients with Low HDL Cholesterol Levels Receiving Intensive Statin Therapy. N Engl J Med 2011; 365:2255-2267.
[4] The HPS2-THRIVE Collaborative Group. HPS2-THRIVE randomized placebo-controlled trial in 25 673 high-risk patients of ER niacin/laropiprant versus placebo. Lancet 2014; 384: 1279–89.
[5] CVD Prevention Group. Nicotinic acid for primary and secondary prevention of cardiovascular disease. Cochrane Database Syst Rev. 2017 Jan 12;1(1):CD003135.
[6] U.S. Food and Drug Administration. FDA Drug Safety Communication: FDA review finds no evidence that niacin or fenofibrates combined with statins provides additional benefit for reducing cardiovascular events. https://www.fda.gov/drugs/drug-safety-and-availability/fda-drug-safety-communication-fda-review-finds-no-evidence-niacin-or-fenofibrates-combined-statins
[7] Morris MC, Evans DA, Bienias JL, et al. Dietary niacin and the risk of incident Alzheimer’s disease and of cognitive decline. J Neurol Neurosurg Psychiatry. 2004 Aug;75(8):1093-9.
[8] ്യHangejorden R, Launer LJ, van den Berg E, et al. Dietary B vitamins and cognitive function in middle and older adults: The CARDIA Study. J Nutr. 2013 Nov;143(11):1701-8.
[9] ClinicalTrials.gov. Studies with niacin and cognitive decline. https://clinicaltrials.gov/search?cond=Cognitive+Decline&term=niacin&intr=Drug
Last reviewed March 2023
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