Niacin, also known as vitamin B3, is an essential water-soluble nutrient that plays a vital role in various bodily functions. It is crucial for proper metabolism, nervous system function, and antioxidant protection. Since the body cannot produce niacin on its own, it must be obtained through food sources. Understanding the foods that contribute significantly to niacin intake is essential for maintaining optimal health.
What is Niacin?
Niacin, or vitamin B3, is a generic descriptor for the closely related compounds, nicotinic acid and its amide nicotinamide, which act similarly as nutrients. Niacin functions as a component of the reduced and oxidised forms of the coenzyme nicotinamide adenine dinucleotide (NADh3 and NAD, respectively), both of which are involved in energy metabolism, and nicotinamide adenine dinucleotide phosphate (NADPh3 and NADP, respectively). These coenzymes function in dehydrogenase-reductase systems involving the transfer of a hydride ion. NAD is also needed for non-redox adenosine diphosphate-ribose transfer reactions involved in DNA repair and calcium mobilisation. It functions as part of the intracellular respiration system and with enzymes involved in oxidation of fuel substrates. Niacin aids your metabolism and nervous system.
Recommended Dietary Allowance (RDA)
The recommended dietary allowance (RDA) for niacin is 16 mg per day for men and 14 mg per day for women. This amount is sufficient to meet the needs of approximately 98% of adults. Since niacin is water-soluble, any surplus is excreted through urine, making regular consumption of niacin-rich foods necessary.
Food Sources of Niacin
Niacin is present in a wide variety of foods, including animal products, plant-based sources, and fortified grains. Important sources of preformed niacin include beef, pork, wholegrain cereals, eggs and cow's milk. Human milk contains a higher concentration of niacin than cows' milk. In unprepared foods, niacin is present mainly as cellular NAD and NADP. Enzymatic hydrolysis of the coenzymes can occur during the course of food preparation. In mature grains, most of the niacin is bound and is thus only 30% available, although alkali treatment of grain increases availability. The niacin in meats is in the form of NAD and NADP and is more bioavailable.
Animal Products
Liver: Liver is one of the best natural sources of niacin. A typical 3-ounce (85-gram) serving of cooked beef liver provides 14.7 mg of niacin, or 91% of the RDA for men and more than 100% of the RDA for women. Chicken liver is also a good source, providing 73% and 83% of the RDA for men and women per 3-ounce (85-gram) cooked serving, respectively. Liver is packed with protein, iron, choline, vitamin A and other B vitamins.
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Chicken Breast: Chicken, especially the breast meat, is a good source of both niacin and lean protein. 3 ounces (85 grams) of cooked, boneless, skinless chicken breast contain 11.4 mg of niacin, which is 71% and 81% of the RDA for men and women, respectively. In comparison, the same amount of boneless, skinless chicken thighs contain only half that amount. Chicken breasts are also packed with protein, containing 8.7 grams per cooked ounce (28 grams).
Tuna: Tuna is a good source of niacin and a great option for people who eat fish but not meat. One 5.8-ounce (165-gram) can of light tuna provides 21.9 mg of niacin, over 100% of the RDA for both men and women. It’s also high in protein, vitamin B6, vitamin B12, selenium and omega-3 fatty acids. Eating one can per week is considered safe for most people.
Turkey: Though turkey contains less niacin than chicken, it provides tryptophan, which your body can turn into niacin. 3 ounces (85 grams) of cooked turkey breast pack 6.3 mg of niacin and enough tryptophan to produce roughly 1 additional milligram of niacin. In combination, this is roughly 46% of the RDA for men and 52% for women. Tryptophan is also used to produce the neurotransmitter serotonin and the hormone melatonin - both of which are important for mood and sleep.
Salmon: Salmon - especially wild-caught - is also a good source of niacin. One cooked 3-ounce (85-gram) fillet of wild Atlantic salmon packs 53% of the RDA for men and 61% of the RDA for women. The same portion of farmed Atlantic salmon contains slightly less - only about 42% of the RDA for men and 49% for women. Salmon is also an excellent source of omega-3 fatty acids, which can help combat inflammation and reduce the risk of heart disease and autoimmune disorders. Wild salmon contains slightly more omega-3s than farmed salmon, but both are good sources.
Anchovies: Eating canned anchovies is an inexpensive way to meet niacin needs. Just one anchovy provides roughly 5% of the RDA for adult men and women. Therefore, snacking on 10 anchovies gives half the niacin needed each day. These small fish are also an excellent source of selenium, containing roughly 4% of the RDI per anchovy. Eating foods rich in selenium is associated with a 22% lower risk of cancer, especially those of the breast, lung, esophagus, stomach and prostate.
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Pork: Lean cuts of pork, such as pork tenderloin or lean pork chops, are good sources of niacin as well. 3 ounces (85 grams) of roasted pork tenderloin pack 6.3 mg of niacin, or 39% and 45% of the RDA for men and women, respectively. In comparison, the same portion of a fattier cut like roasted pork shoulder contains just 20% of the RDA for men and 24% of the RDA for women. Pork is also one of the best food sources of thiamine - also known as vitamin B1 - which is a key vitamin for your body’s metabolism.
Ground Beef: Ground beef is a good source of niacin and rich in protein, iron, vitamin B12, selenium and zinc. Leaner varieties of ground beef contain more niacin per ounce than fattier products. For example, one 3-ounce (85-gram) cooked serving of 95% lean ground beef provides 6.2 mg of niacin, while the same amount of 70% lean ground beef contains just 4.1 mg. Some research has found that grass-fed beef offers more heart-healthy omega-3 fatty acids and antioxidants than conventional grain-fed beef, making it a highly nutritious option.
Plant-Based Sources
Peanuts: Peanuts are one of the best vegetarian sources of niacin. Two tablespoons (32 grams) of peanut butter contain 4.3 mg of niacin, roughly 25% of the RDA for men and 30% for women. Peanuts are also rich in protein, monounsaturated fats, vitamin E, vitamin B6, magnesium, phosphorus and manganese. While peanuts are relatively high in calories, research shows that eating them daily is associated with health benefits like a reduced risk of type 2 diabetes. Additionally, daily peanut consumption does not lead to weight gain.
Avocado: One medium avocado contains 3.5 mg of niacin, or 21% and 25% of the RDA for men and women, respectively. They’re also rich in fiber, healthy fats and many vitamins and minerals. Avocados are also excellent sources of monounsaturated fats, which may help reduce the risk of heart disease when consumed regularly.
Brown Rice: One cup (195 grams) of cooked brown rice contains 18% of the RDA for niacin for men and 21% for women. However, some research suggests that only 30% of the niacin in grains is available for absorption, making it a less optimal source than other foods. In addition to its niacin content, brown rice is high in fiber, thiamine, vitamin B6, magnesium, phosphorus, manganese and selenium. Swapping out white rice for brown has been shown to reduce inflammation and improve markers of heart health in overweight and obese women.
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Whole Wheat: Whole-wheat products - such as whole-wheat bread and pasta - are also high in niacin. That’s because the niacin-rich outer layer of wheat kernels - known as the bran - is included in whole-wheat flour but removed from refined white flour. For example, one whole-wheat English muffin contains roughly 15% of the RDA for men and women, but an English muffin made from unenriched white flour supplies only about 5%. However, like brown rice, only about 30% of the niacin in whole-wheat products is digested and absorbed.
Mushrooms: Mushrooms are one of the best vegetable sources of niacin, providing 2.5 mg per cup (70 grams) - that’s 15% and 18% of the RDA for men and women, respectively. This makes these tasty fungi a good option for vegetarians or vegans looking for natural sources of niacin. Mushrooms grown under sunlamps also produce vitamin D and are one of the best plant-based food sources of this vitamin. Interestingly, studies have found that consuming vitamin D through mushrooms is as effective as supplements for raising vitamin D levels in deficient adults.
Green Peas: Green peas are a good vegetarian source of highly absorbable niacin, boasting 3 mg per cup (145 grams) - about 20% of the RDA for both men and women. They’re also rich in fiber, at 7.4 grams per cup (145 grams). One cup of green peas supplies over 25% of the daily fiber needs for someone consuming 2,000 calories per day. Studies show that peas are also high in antioxidants and other compounds that may reduce the risk of cancer, lower cholesterol levels and promote the growth of healthy gut bacteria.
Potatoes: White potatoes are a good source of niacin - with or without the skin. One large baked potato provides 4.2 mg of niacin, which is roughly 25% of the RDA for men and 30% for women. According to one review, brown Russet potatoes pack the highest amount of niacin out of any type of potato - with 2 mg per 100 grams. Sweet potatoes are also a good source, providing roughly the same amount of niacin as the average white potato.
Fortified and Enriched Foods
Many foods are fortified or enriched with niacin, transforming them from poor sources of this nutrient to good ones. Fortified foods are supplemented with extra nutrients, while enriched foods have nutrients added back that had been lost during processing. Many breakfast cereals and refined grain products like white bread and pasta are enriched or fortified with niacin to improve their nutrient content. One study found that the average American gets more niacin in their diet from fortified and enriched products than from natural food sources.
Niacin Deficiency
Deficiency of niacin causes the disease pellagra which is associated with inflammation of the skin on exposure to sunlight, resembling severe sunburn except that the affected skin is sharply demarcated. These skin lesions progress to pigmentation, cracking and peeling. Often the skin of the neck is involved. Pellagra is the disease of 'three Ds', namely dermatitis, diarrhoea and (in severe cases) delirium or dementia. There is also likely to be an inflamed tongue (glossitis). In mild chronic cases, mental symptoms are not prominent. Pellagra was a major problem in the Southern states of the US in poor Blacks and Whites whose diet consisted of maize (American corn) and little else. Unlike other cereals maize is low in bioavailable niacin and tryptophan is the first limiting amino acid.
While uncommon in Western countries, it is possible to develop a niacin deficiency. Symptoms include tiredness, poor circulation, canker sores, stomach issues, and depression. Untreated, it can lead to a condition called pellagra.
Benefits of Niacin
Like other B vitamins, niacin plays a role in many functions throughout the body. The body uses it for such things as proper nervous system functions and metabolism. The vitamin also plays a role in heart, digestive, skin, and brain health:
Heart Health: Niacin helps to regulate cholesterol and protect the health of your heart. It can aid in reducing LDL cholesterol, raising HDL cholesterol, and improving triglyceride levels. The vitamin also acts as an antioxidant, which can further protect your heart. As an antioxidant, it helps to reduce oxidative stress and inflammation, both of which can contribute to atherosclerosis, or narrowed arteries due to plaque buildup.
Digestive Health: Niacin plays an important part in breaking down fats, carbohydrates, and alcohol in the digestive system. Having enough vitamin B3 also helps to prevent pellagra, which causes digestive issues such as vomiting and diarrhea, along with other symptoms.
Skin Health: Niacin may help to keep your skin cells safe from sun damage. Some studies also show that the vitamin may also play a role in preventing certain types of skin cancer.
Brain Health: Your brain needs niacin to function properly. Insufficient amounts of B3 could result in too little energy to the brain, which could lead to brain fog. It may even lead to symptoms of schizophrenia.
Indicators of Niacin Status
Indicators that have been used to assess niacin requirements include urinary excretion, plasma concentrations, erythrocyte pyridine nucleotides, transfer of adenosine diphosphate ribose and appearance of pellagra. Biochemical changes appear well before overt signs of deficiency. The most sensitive and reliable measure of niacin status is the urinary excretion of its two major methylated metabolites, N1-methyl-nicotinamide and N1-methyl-2-pyridone-5-carboxamide. Excretion rates in adults of more than 17.5 micromol/day of these two metabolites reflect adequate niacin status, while excretion rates between 5.8 and 17.5 micromol/day reflect low niacin status. An adult has deficient niacin status when urinary excretion rates are less than 5.8 micromol/day.
Niacin Supplements
Niacin is available in multivitamin/mineral products, in supplements containing other B-complex vitamins, and in supplements containing niacin only. Nicotinic acid and nicotinamide are the two most common forms of niacin in supplements. Nicotinic acid in supplemental amounts beyond nutritional needs can cause skin flushing, so some formulations are manufactured and labeled as prolonged, sustained, extended, or timed release to minimize this unpleasant side effect. Nicotinamide does not produce skin flushing because of its slightly different chemical structure. Niacin supplements are also available in the form of inositol hexanicotinate, and these supplements are frequently labeled as being flush free because they do not cause flushing.