- New research shows high levels of niacin has been linked to an increased risk of heart disease.
- Niacin, also known as vitamin B3, is found in foods like meat, poultry, fortified breads and cereals, and bananas.
- Researchers recommend that people should stop taking niacin supplements unless there is a medical need for them.
New research suggests that too much of the essential B vitamin niacin can contribute to cardiovascular disease.
The study, recently published in Nature Medicine, found a strong association between high levels of the vitamin and the risk of developing a heart attack, stroke, or other dangerous cardiac event.
Researchers also discovered that excess niacin may directly affect cardiovascular health by triggering vascular inflammation, which can cause the walls of blood vessels to thicken. This thickening may restrict blood flow, potentially damaging tissues and organs—including the heart.
Niacin (vitamin B3) is found in many foods, from meat and fish to bananas and fortified breads. Most people in the United States don’t have to take a niacin supplement because they get enough from their diet.
Still, about one in four Americans have higher than the recommended level of niacin in their bodies, according to senior author Stanley Hazen, MD, PhD, chair of cardiovascular and metabolic sciences at the Cleveland Clinic’s Lerner Research Institute and co-section head of preventive cardiology at the Heart, Vascular, and Thoracic Institute.
The researchers want the study to spur a conversation about whether niacin should be eliminated from certain fortified foods, such as flour and cereal.
“The main takeaway is not that we should cut out our entire intake of niacin—that’s not a realistic or healthy approach. Niacin is a vitamin and essential to our health,” Hazen told Health. “But an excess amount appears to be a concern.”
Luke Chan / Getty Images
How Niacin Affects Heart Health
The researchers wanted to hunt for any markers in blood that might reveal new risk factors for cardiovascular disease. To do this, they analyzed the fasting blood samples of 1,162 patients who had gone to a cardiology center to be evaluated for heart disease.
They discovered that some of the blood samples showed 4PY, a substance produced only when there is excess niacin.
In light of this, researchers then conducted two “validation” studies examining data from 3,163 adults in the U.S. and Europe who either had heart disease or were suspected of having it. They found that people with 4PY in their blood had a higher chance of having a heart attack, stroke, or other adverse cardiac event.
Based on these findings, the scientists then injected mice with 4PY—discovering that it increased inflammation in the rodents’ blood vessels.
“Mechanistic studies show 4PY is linked to vascular inflammation and directly promotes cardiovascular disease-related phenotypes in animal models and in cell culture,” Hazen said. “These findings provide a foundation for potential new interventions and therapeutics to reduce or prevent vascular inflammation—a precursor and participant in atherosclerotic cardiovascular disease.”
The study may also help explain previous research showing that people with high cholesterol who took niacin supplements—a proven way to help lower cholesterol—still continued to have strokes and heart disease.
Should You Still Consume Niacin?
Niacin is a nutrient our bodies need to function. It plays a crucial role in converting food into energy and supporting the nervous system, and may even promote skin health.
Because the body doesn’t produce niacin, people need to consume it—the National Institutes of Health says that the Recommended Dietary Allowance (RDA) is 16 milligrams (mg) daily for men and 14 mg for women. The RDA is a bit higher for women who are pregnant or lactating.
Fortunately, niacin can be found naturally in foods such as nuts, seeds, and whole grains. It is also added to products such as flour and cereal, something food manufacturers began doing after scientists discovered in 1937 that a niacin deficiency caused pellagra, a fatal form of malnutrition.
“For decades, the U.S. and more than 50 nations have mandated niacin fortification in staple foods such as flour, cereals, and oats to prevent disease related to nutritional deficiency,” said Hazen. “This has been a tremendous health benefit in terms of reducing these nutritional deficiencies. For example, pellagra virtually does not exist any longer in the United States.”
In light of the study, however, researchers think it’s time for the U.S. to reexamine policies around adding niacin to food products.
And when it comes to taking a niacin supplement, Hazen suggests consulting a doctor. Not only do most people not need it, but the study shows that consuming too much niacin may even cause cardiovascular harm.
