Niacin, also known as vitamin B3, is found in one of three chemical forms: nicotinic acid, inositol hexanicotinate, and niacinamide. Each of the three forms may result in a different reaction in the body. For example, niacinamide and inositol hexanicotinate are forms of niacin that do not cause flushing, whereas nicotinic acid dilates the blood vessels and can cause reddening of the skin, itching, or other discomfort. The side effects of flushing are often temporary, lasting around 10 minutes. Taking a cold shower or sitting outside on a cool day is sometimes enough to alleviate flushing.
The form of niacin may be less important in a multivitamin, a B vitamin supplement, or in a supplement containing niacin in low levels. In higher doses, selecting the right form of niacin may be important. However, the form of niacin that causes flushing is attributed to a number of potential cholesterol and brain benefits. While all niacin is essential, the specific type may affect what result an individual will experience.
Why Does Niacin Matter?
Niacin is one of the eight B vitamins that when combined is known as a vitamin B complex. All B vitamins serve as cofactors that help to begin a biochemical reaction or help to progress a reaction towards completion.(1) B vitamins are best understood for the role they play in metabolism and energy production; however, they are also essential for hundreds of other functions that affect the brain, heart, digestion, DNA synthesis, and more. A deficiency of niacin or one of the other B vitamins can result in disruptions in the healthy functions of the body.
When found in food or taken as a supplement, healthy levels of niacin in the body support:(2)(3)(4)
- Cholesterol levels already in the normal range
- Heart health
- Glucose levels
- Healthy-looking skin
- Brain function
- Learning, memory, focus, behavior
- Nerve health
- Healthy joints
- Reproductive health
- Energy production
- And more
The History of Nutritional Deficiencies
Nutritional deficiencies were common throughout human history and remain an issue in developing countries today.(5) But poor nutrition does not mean a person doesn’t have food. In fact, nutritional deficiencies are often linked to diets that relied heavily on bread and salted meat. These foods are typically favored because they store well during the winter, won’t easily spoil over long journeys, and access to them is much easier when compared to fruits and vegetables.(6)
Failing to get the right amount of nutrition causes disruptions in normal bodily functions that can result in the form of disease. Pellagra is a disease that occurs in people that fail to get enough niacin in their diet. While a lack niacin is the primary cause of pellagra, people can ingest enough niacin to meet their daily dietary needs but still be diagnosed with pellagra. This is often a result of chronic alcoholism, gastrointestinal disorders, and some medications decrease the absorption of niacin.(7)
Pellagra is diagnosed based on individual history and the presence of ‘3 D syndrome,’ which presents itself as dermatitis, diarrhea, and dementia. The effects of each condition will progress in severity from general discomfort, to tissue damage, and ultimately death if left untreated. In most cases, treatment is enough to reverse tissue damage.(8)
The Discovery of Niacin
The disease we know today a pellagra wasn’t well documented before the Middle Ages (1300-1500.) It wasn’t until the 1700s with the introduction of maize (corn) in Europe cases of pellagra became documented. Maize proved problematic because the kernel offers only a small amount of B vitamins, dietary fiber, and protein. Maize is a good source of metabolic energy but lacks the nutritional value that humans need from a primary food source.(9) (10)
Nutritional issues became such a problem in Europe that in Legnago, Italy, a hospital was built specifically to try and help people suffering pellagra related symptoms.(11) Records of pellagra show that the disease also became problematic throughout the 1800s in France, Romania, and Egypt. In the early 1900s, pellagra spread through the American south, notably Alabama. Dr. George H. Searcy first became aware of pellagra in America when 88 patients in the Mount Vernon Insane Hospital, Mt. Vernon, Alabama, were found to exhibit a similar set of symptoms.
His findings were widely debated as speculation grew about a new form of contagious disease. Some researchers even attributed these health problems to racial or hereditary factors, as the patients were all of African descent. It wasn’t until 1912 that Polish-American biochemist Casimir Funk found the connection between pellagra and nicotinic acid. Specifically that a compound found in the brown casings of grains contained compounds similar to those found in chemicals used in photography during the 1800s. This finding allowed Funk to speculate that there were certain factors in foods that might be important in a diet. However, Funk’s focus was on curing beriberi (a deficiency of vitamin B1 – thiamine), of which nicotinic acid wasn’t a cure. So Funk abandoned the research of nicotinic acid, but his contributions still proved invaluable.
Later, Austrian-American physician Joseph Goldberger used Funk’s research to discover that he could induce pellagra by changing the diet of 11 healthy volunteers. This diet became known as the ‘Goldberger Diet.’ In 1937, American biochemist Conrad Arnold Elvehjem built upon Goldberger’s work and fed dogs the ‘Goldberger diet’ to induce pellagra and then subsequently cured it by supplementing the diet with nicotinic acid. As a result of this work, grain products would later be ‘fortified’ or ‘enriched’ with niacin, and other vitamins in the coming decades, as they were discovered to help reduce or eliminate health problems related to poor diets.
Potential Niacin Benefits
Many of niacin’s potential benefits are linked with its ability to dilate vessels and arteries. However, only nicotinic acid causes this effect. Other forms of niacin, also known as ‘flush free’ niacin, are not known to cause this effect in the body. Whether or not flush free niacin provides the same potential benefits isn’t entirely known; however, every form of niacin is essential to hundreds of process within the body.
Cholesterol is a compound that supports the development and function of several components in the body. There are three type of cholesterol that move through the body known as low-density lipoproteins (LDL), high-density lipoproteins (LDL), and triglycerides (a type of fat). Each form of cholesterol is a measure of the amount of cholesterol carried by lipoproteins in the blood.(12)
HDL cholesterol is known as ‘good’ cholesterol because indicates there is a higher level of protein and lower level of cholesterol found attached to lipoproteins. LDL is considered ‘bad’ cholesterol due to the higher level of cholesterol and lower levels of protein, which increases the chance of cholesterol plaque forming on the inside of artery walls. Doctors use the measure of cholesterol as an indicator for the likelihood of experiencing a cardiovascular event (heart disease, heart attack, stroke, valve failure, etc.) (13)
In clinical trials, niacin has been found to be beneficial as part of a primary therapy to help treat lipid abnormalities, including unfavorably low HDL cholesterol levels.(14) A study examining the effect of niacin on cholesterol factors found that niacin has a “potent effect on HDL levels.” (15) According to the data presented, triglycerides and LDL cholesterol were reduced by 20% and 14%, and HDL cholesterol was increased by 16%. The study concluded that there is an estimated 27% reduction in risk for major coronary events with using niacin to lower HDL cholesterol.
Fatty deposits in the cardiovascular system are known to create both local and systemic inflammation that is associated with “an increased risk of future myocardial infarction, stroke, peripheral vascular disease, and cardiovascular death.” (16)
Current research has suggested that niacin helps to regulate gene expression and hormone production involved in pro-inflammatory factors.(17)(18) In response to internal challenges, the immune system will produce compounds that seek to protect the body but in some situations this results in inflammation that can cause swelling or long-term cellular damage. Niacin has been shown to be lipid-independent, meaning that its protective qualities may be beneficial to every patient, regardless of cholesterol levels in the body.(19)
Blood pressure is a concern of some groups of people and is a noted risk factor for cardiovascular disease.(20) Small clinical trials that measure the effect of niacin on blood pressure have “shown significant BP-lowering effects of niacin in patients with hypertension.” In similar studies, niacin has almost no lowering effect on those with blood pressure levels already within the normal range. Comparatively, some large scale studies could not find a clear link between niacin and blood pressure, despite the research showing data that supports the initial claim that hypertensive blood pressure did decrease.
The source of niacin’s blood pressure lowering effects is believed to be related to its regulation of the immune system, inflammatory factors, and regulation of insulin and blood glucose levels.(21) Additionally, the dilation of vessels and arteries may also be a contributing factor. But further research is needed to understand both the short and long term effects of niacin’s influence on the cardiovascular system.(22)
Niacin is understood to support the expression of certain genes that affect the long term health of the body. To further understand niacin’s potential benefits for aging individuals, research has sought to identify links between niacin and neural degeneration.(23) While research into this area of study remains limited, researchers have suggested that niacin treatments may increase synaptic plasticity, function, neuronal survival. This may be in part due to how HDL cholesterol is used in the development of bodily systems. Niacin helps to improve HDL cholesterol, which may be a contributing factor. Future studies may look to niacin as a method to target “treatment of neurodegenerative disorders also like Alzheimer's and Parkinson's diseases, and for the re-innervation of tissues after injury.”
A study from East Carolina University, Greenville, North Carolina identified niacin as a potential tool to improve recovery and reduce a certain expression of protein following traumatic brain injury (TBI).(24) In the university’s animal study, researchers found that the administration of niacin “significantly improved behavioral outcome following injury, reduced the size of the lesion, and reduced the expression of glial fibrillary acidic protein (GFAP.) The current findings suggest that vitamin B3 may have therapeutic potential for the treatment of TBI.”
Several research studies have identified niacin as a potential treatment for migraines and tension-type headaches. (25) Much of niacin's potential support for temporary or complete relief from pain may be due to its “vasodilatory properties and its ability to improve mitochondrial energy metabolism.” This means that niacin helps to relax or open vessels and arteries to reduce strain on surrounding tissue. Additionally, it may improve energy production in brain tissue. Low energy production in the brain has been linked to chronic migraine headaches. (26) However, the research notes that the impact of niacin on head pain should not be overstated and requires further research.
Joint and Mobility Support
In a pilot study looking to identify the potential benefits of niacinamide on osteoarthritis, 72 patients with the disease were treated with either niacin or a placebo. (27) Researchers measured “global arthritis impact and pain, joint range of motion and flexibility, erythrocyte sedimentation rate (a measure of red blood cells and inflammation), complete blood count, liver function tests, cholesterol, uric acid, and fasting blood sugar.” The study noted that patients receiving the niacin treatment experienced a reduction to inflammation and increased joint mobility.
Niacin may have several positive and negative side effects on the skin. itching, flushing, and other discomforts are common when taking larger doses of niacin. However, niacin is believed to help stabilize the epidermal barrier (outer layers of skin), which may help to maintain water content in the skin. (28) Additionally, niacin may also support protein synthesis in the skin for support of healthy-looking skin, including skin appearance, texture, and tone.
Niacin is also suggested to help protect skin cells against UVB damage in epidermal cells that produce keratin, the outer protective layer of hardened skin cells. One study found that niacin induces activation of AKT (pathways that promote survival and growth in response to extracellular signals) and helps to modulate signaling pathways that may be susceptible to damage from sunlight. (29)(30)
Vitamin B3 - Niacin Dosing
When looking at the Recommended Dietary Allowances (RDA) of niacin, the suggested intake levels represent the amount of niacin that is sufficient for at least 97% of individuals. Daily requirements may depend on individual health, prescriptions, or OTC medications.
Tolerable Upper Intake Levels For Niacin
There is insufficient evidence to set tolerable upper intake levels for niacin from food sources or supplements. To try and identify the effects of higher doses, a study measured patients receiving 1500 mg and 3000 mg of niacin as a supplement each day. In the study, nearly 80% of patients experienced gastrointestinal tract problems, fatigue, and an increase of symptoms associated with hepatic dysfunction in the liver. (31) Naturally occurring niacin found in food is considered safe at most levels of intake. If changes to health occur when supplementing a healthy diet with niacin immediately consult with a doctor.
Niacin Food Sources
Dietary choice will affect the type and quantity of vitamins an individual receives. Some foods that may be ideal for meeting daily dietary requirement includes: (32)
- Poultry (turkey)
- Fortified or enriched pastas and breads
- Ready-to-eat cereals
- Beef, pork, lamb
- Dairy products
- Squash, pumpkin, gourds
- Plant seeds
- Marmite or vegemite
- Greens (avocado, lentils, peas, etc.)
Niacin in cereal grains was found to be 30% available for absorption in the stomach and upper section of the digestive tract. (33) Niacin that naturally occurs in meat has been suggested to have greater bioavailability. However, there is insufficient data to determine precise bioavailability from different food types.
Niacin content might not be on food labels. The FDA does not require food labels to list niacin content unless the food has been fortified with this nutrient. Niacin is frequently added to grains found in pasta and cereals. If food is not enough to meet daily recommended levels of nutrients, then supplementation may be ideal.
Niacin Side Effect and Warnings
The most common symptom of taking niacin as nicotinic acid is flushing, which can result in warmth, redness, itching, or tingling. (34) These symptoms may last as little as 10 minutes or persist and negatively affect the face, arms, and chest. These symptoms are reported to most commonly occur in oral doses of at least 30 mg. Flushing is largely attributed to a rise in plasma nicotinic acid concentrations rather than any specific dosage amount. Nausea, vomiting, and signs of liver toxicity have been observed when taking high doses of niacin in excess of 1,500 mg per day. When taken as niacinamide or inositol hexanicotinate, flushing is not normally reported. (35)
High doses of niacin have been found to negatively affect the eyes. Blurred vision, loss of visual detail, and the growth of cysts in the fluid found in the eye have been reported in doses that exceed 1,500 mg per day. Stopping or limiting niacin intake was found to reverse symptoms that affect the eyes. Dizziness, insomnia, nervousness, coughing, decreased glucose tolerance, hepatitis, and hypersensitivity have been reported when ingesting niacin as a supplement.
Not all niacin supplements are formulated the same way with some supplements containing additional vitamins, herbs, and extracts that might alter the effect of vitamins in the body. If taking another supplement while using a niacin supplement, unexpected interactions could occur.
Begin a Vitamin B3 – Niacin Supplement Regimen
Niacin and vitamin B3 supplements can help to fill nutritional gaps and help individuals to meet daily dietary needs. Niacin supplements are available for adults and children in the form of capsules, chewables, sprays, liquids, or gummies. Niacin can also be found in multivitamins and B complex supplements. Exercise aids such as energy bars and powdered drink mixes may also contain niacin.
The understanding of nutrition has changed a lot in human history. Today, it is known that a mix of carbohydrates, proteins, fats, vitamins, and minerals will provide the body with the compounds it needs to function normally. Even if certain foods are not readily available, modern innovations such as supplements make it easier than ever to meet dietary needs. Find a niacin supplement that works for you, and see if it makes a difference in your life.