Niacin, also called vitamin B3, plays a vital role in regulating energy production and cholesterol levels in the blood. Most people get the amount of niacin they need through food, but in some cases, people may take additional niacin as a dietary supplement or prescription medication.
Read below to learn more about the health benefits, possible side effects, dietary sources, and more.
What Does Niacin Do?
Inside cells, niacin is converted into the bioactive molecules nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP).
NAD and NADP are vital for metabolism – the production of energy from carbohydrates and sugar within cells. They also play other essential roles inside cells such as:
- Controlling gene expression
- Counteracting the harmful effects of oxidative stress
- Helping maintain communication between cells
- Making fatty acids
What Is Niacin Good For?
Because niacin aids metabolism, it’s important for cellular health. It helps make energy available for cells to function correctly.
The antioxidant properties of NAD and NADP mean niacin also helps reduce cellular damage by decreasing the harmful effects of oxidative stress.
Effects on Fat Production
Niacin increases the production of high-density lipoprotein (HDL), also known as “good” cholesterol, and decreases the amount of low-density lipoprotein (LDL), known as “bad” cholesterol in the blood.
Niacin’s effect on cholesterol is important for maintaining a healthy balance of fats.
Whereas HDL helps move fat into the liver to be excreted from the body, LDL can move fat into the blood vessels, which can cause heart disease and blood vessels to become blocked. Therefore, niacin’s effect on cholesterol is important for maintaining a healthy balance of fats.
Increases Blood Flow
Niacin increases the production of prostaglandins, which are molecules that cause blood vessels to widen. This effect increases blood flow which helps improve circulation and can help to lower blood pressure in people suffering from hypertension (high blood pressure).
Scientists have found that niacin can decrease the action of pro-inflammatory mediators. Pro-inflammatory mediators are molecules whose function is to attack harmful microorganisms but if overactivated, can attack and damage human cells, leading to several diseases.
Niacin could therefore have a protective role in preventing immune system-related damage and disease.
Niacin Health Benefits and Uses
Treatment and Prevention of Pellagra (Niacin Deficiency)
Pellagra is a disease caused by a deficiency of niacin or deficiency of tryptophan, an amino acid involved in the production of niacin. The symptoms of pellagra are characterized by the three D’s: dementia, diarrhea, and dermatitis.
In most circumstances, pellagra can be treated by increasing dietary intake of niacin or taking niacin supplements. However, in cases where pellagra is caused by a lack of ability to absorb niacin, such as in people with gastrointestinal disorders, medical professionals will deliver niacin by intravenous injection.
Treatment of Dyslipidemia
Dyslipidemia is a condition in which people have abnormal levels of fats in the blood. People with dyslipidemia tend to have an abnormally high concentration of LDLs and triglycerides (another type of fatty molecule) and an abnormally low concentration of HDLs. This imbalance can lead to swellings, pain, and an increased risk of artery disease.
Because of its effects on controlling blood lipids, niacin is an effective treatment for dyslipidemia. Several studies have also highlighted how niacin treatment is associated with a reduced risk of coronary artery disease in dyslipidemia patients.
Could Help Prevent Cognitive Decline
Because niacin helps protect against oxidative stress and aids the metabolic health of nerve cells in the brain, niacin could be helpful to protect against age-related brain damage.
One study investigating over 3700 people found an association between increased niacin in the diet and decreased risk of developing Alzheimer’s disease. Another study found that young adults who had more niacin in their diet showed better cognitive functioning in later life.
Researchers found that young adults who had more niacin in their diet showed better cognitive functioning in later life.
However, it’s important to consider that these associations don’t necessarily mean one thing causes another, as other factors may be involved.
Researchers also highlighted the neuroprotective effects of niacin in an animal study that demonstrated that NAD could reverse DNA damage and memory loss in a model of Alzheimer’s disease.
May Be Helpful in Preventing Heart Disease
Niacin’s effects on LDL mean it may help reduce the risk of heart disease caused by atherosclerosis (a build-up of fat in the walls of blood vessels) and is effective at decreasing blood pressure in people with hypertension. In theory, these combined effects could decrease the risk of life-threatening cardiac events such as strokes, aneurysms, and heart attacks.
However, one review of 23 different studies found that niacin had no significant effect on reducing the number of heart attacks or strokes in elderly patients.
Furthermore, studies have demonstrated that taking niacin in combination with statins (heart disease medications) increases the likelihood of liver injury compared to statins alone.
Side Effects of Niacin
The most common side effect of niacin is the “niacin flush,” where the skin becomes red and itchy, and people may experience uncomfortable and burning sensations. This effect happens because of a widening of the blood vessels in the skin and is only noticeable with larger doses.
As well as flushing, other side effects of niacin can include:
- Abdominal pain
- Blurred vision
Additionally, long-term niacin intake can have long-term harmful effects on the liver.
Forms of Niacin
Foods High in Niacin
Foods high in niacin content include:
- Red meat: beef and pork, beef liver has the highest content at around 14.9 mg per serving.
- Poultry: chicken and turkey, chicken breast has the highest content at around 10.3 mg per serving.
- Seafood: tuna and salmon, salmon has the highest content at around 8.6 mg per serving.
- Fortified cereals and bread
- Legumes: peanuts, lentils, and chickpeas. Peanuts have the highest content at around 4.2 mg per serving.
- Nuts and seeds: pumpkin seeds, sunflower seeds, and cashews. Pumpkin seeds have the highest content at around 2 mg per serving.
- Brown rice
The amount of niacin found in foods is only a fraction of the dose required to impact cholesterol levels significantly. This reason, alongside the other health benefits of niacin, means some people may use niacin as a dietary supplement alongside niacin in their diet.
These dietary supplements may contain niacin alone or niacin along with other vitamins and minerals, such as B-vitamin complexes and multi-vitamin tablets.
Nicotinamide is the broken-down version of niacin, which people can also buy as a dietary supplement. Unlike niacin, nicotinamide doesn’t cause flushing, making it a preferable option for some. However, nicotinamide doesn’t have the same cholesterol-lowering benefits of niacin.
As well as supplements, niacin comes in pill and capsule form as a prescription medication for dyslipidemia.
A typical version of prescription niacin is extended-release pills. The slower release of niacin over a given time in these types of pills reduces the likelihood of side effects.
Niacin Recommended Dosage
The Recommended Dietary Allowance (RDA) for niacin is as follows:
- Children: 2-12 mg per day
- Adolescents: 12-16 mg per day
- Adults: 16-18 mg per day
The Tolerable Upper Intake Level (UL) is the maximum dose unlikely to cause adverse side effects. For niacin, the UL is around 35 mg per day. However, because the main side effects are relatively non-harmful, store-bought supplements intended for daily use may contain up to 1000 mg.
Niacin Dosage for High Cholesterol
Researchers have generally used doses from around 1000mg niacin per day in clinical trials where niacin has demonstrated a significant effect on cholesterol.
Importance and Benefits of Niacin: A Summary
Its metabolic, antioxidant, and LDL-cholesterol lowering effects make niacin an essential vitamin for maintaining health. A deficiency of niacin can be detrimental by causing pellagra and potentially increasing the risk of heart disease and cognitive decline.
Some people increase their niacin intake with dietary supplements to boost the likelihood of beneficial effects.
Most people get the amount of niacin they need per day through their diet. However, some people may choose to up their niacin intake with dietary supplements to increase the likelihood of beneficial effects. Doctors may also prescribe niacin to patients to help treat certain conditions.
If you’re considering using niacin, be sure to consult with a health professional first, as they will be able to provide specialist advice based on your individual needs and interactions with other medications you may be taking.
How much niacin should I take per day?
The general niacin recommendation for adults is between 16-18mg per day. However, if your reasoning for taking niacin is to improve blood cholesterol levels, you may require a much higher dose. In which case, please speak with your physician as they will be able to recommend or prescribe you suitable supplements or pills.
How long does a niacin flush last?
The symptoms of a niacin flush tend to kick in around 15-30 minutes after ingesting niacin and last around an hour. You may be able to reduce the likelihood of a niacin flush by consuming niacin alongside food or aspirin (source).
How much niacin is too much?
The upper dose limit of niacin is 35 mg per day. However, most of the side effects are non-harmful and end once the drug has worn off. More dangerous side effects tend to occur when niacin is taken from doses around 2000 mg and above.
There have been few reported deaths linked to niacin. However, in one case report, long-term use of 1500 mg niacin per day resulted in liver failure and death.
What foods have niacin?
See above under the heading “forms of niacin.”
How long does niacin stay in your system?
Based on the half-life of niacin, niacin is predicted to be eliminated from the body from around 2-4 hours after ingestion. However, this value will vary based on your metabolic rate, body weight, the dose that is taken, and whether you’ve taken niacin with food.