Vitamin Once Recommended for Heart Health May Increase Risk
- Niacin has been linked to a higher risk of heart disease.
- It is often added to flour and fortified cereals in the U.S.
- The B vitamin used to be a popular medication to lower high cholesterol.
High levels of niacin, a B vitamin that’s found in many foods and added to fortified cereals and breads, can raise the risk of heart disease, according to new research.
A study published in Nature Medicine revealed that elevated levels of niacin can cause inflammation and harm blood vessels. Researchers analyzed blood samples from 1,162 individuals assessed for heart disease, searching for common markers that might help identify new risk factors for the condition.
Their findings highlighted a substance called 4PY, which forms when the body has an excess of niacin. This compound was strongly associated with patients who had experienced heart attacks, strokes, or other cardiac events.
Moreover, the study showed that 4PY directly triggers vascular inflammation, damaging blood vessels and contributing over time to atherosclerosis—the buildup of fats, cholesterol, and other substances in the arteries.
One in four study participants seemed to be getting too much niacin and had high levels of 4PY in their blood. But the researchers also pointed out in the study that they don’t know how much niacin is unhealthy.
The study raises a lot of questions about niacin and its impact on heart health. Ahead, experts share what you need to know.
What is niacin (vitamin B3)?
Niacin, also known as vitamin B3, is a water-soluble vitamin essential for overall health, according to the National Institutes of Health (NIH). “It’s a micronutrient we must obtain from external sources, like food and supplements,” says Scott Keatley, R.D., co-owner of Keatley Medical Nutrition Therapy.
To help prevent nutritional deficiencies, niacin is often added to foods such as flour, bread products, and fortified cereals. Naturally, you can find it in foods like chicken, turkey breast, salmon, and sunflower seeds, according to the NIH.
Once consumed, niacin converts into NAD+ (nicotinamide adenine dinucleotide), which is crucial for energy production, fatty acid breakdown, DNA repair, cell communication, and antioxidant defenses, explains Keatley. Additionally, niacin can transform into niacinamide, which supports skin health and protection.
For adults, the recommended daily intake is 16 milligrams for men and 14 milligrams for women.
Does niacin affect heart health?
Niacin’s role in heart health is a bit of a mixed bag. Prescription medications like Niaspan and its generic version, niacin ER, provide 500 to 1,000 milligrams of extended-release niacin and have been used to treat high cholesterol levels, according to the NIH.
However, in recent years, the effectiveness of these medications for lowering cholesterol has been called into question, as studies haven’t consistently supported their benefits.
“Niacin is essential for our health—we can’t produce enough of it on our own, so we need to get it from our diet,” explains Dr. Stanley Hazen, M.D., Ph.D., chair of the Department of Cardiovascular & Metabolic Sciences at the Cleveland Clinic.
“That said, niacin is rarely prescribed anymore for lowering cholesterol. We now have many other methods that are far more effective at reducing cholesterol and lowering the risk of cardiovascular disease.”
But the latest study takes things a step further, suggesting that niacin in the form of its breakdown metabolite 4PY actually raises the risk of heart attack and stroke.
“This study will put another nail in the coffin for the use of niacin in heart disease,” says Cheng-Han Chen, M.D., board-certified interventional cardiologist and medical director of the Structural Heart Program at MemorialCare Saddleback Medical Center in Laguna Hills, CA.
Who should avoid niacin?
Dr. Chen emphasizes that more research is needed to determine the appropriate dosage of niacin and its impact on cardiovascular health. “At this point, I would advise against taking niacin supplements regularly unless advised by a healthcare provider,” he says.
Keatley clarifies that the recent study results don’t suggest that consuming fortified bread or cereal will increase your risk of heart disease. “The recommended daily allowances (RDAs) for niacin are between 14 to 18 milligrams, while the study involved much higher doses—500 to 2,000 milligrams,” he explains.
“To reach 500 milligrams of niacin from enriched flour, which is one of the main sources, you would need to consume about 30 pounds of it daily.”
Keatley adds that the people who should be most concerned are those taking high doses of niacin for managing cholesterol.
“The key takeaway isn’t that we should eliminate niacin from our diets entirely—this would not be practical or healthy,” says Dr. Hazen. “Instead, this research raises questions about whether it’s time to reconsider the continued fortification of flour and cereal with niacin in the U.S.”
Are there any benefits of niacin?
Niacin offers several benefits, particularly when taken in low doses. It plays a crucial role in energy metabolism, supports neurological health, and helps maintain healthy skin, according to Keatley.
At higher doses, niacin has been used to manage high cholesterol and triglyceride levels. It can lower LDL (“bad”) cholesterol and raise HDL (“good”) cholesterol. However, Keatley emphasizes that using niacin for this purpose should be done under the supervision of a healthcare provider.
Dr. Chen also notes that the use of niacin in high doses for cholesterol treatment is becoming less common.
Does niacin help with clogged arteries?
This is a complicated question. Older research suggested that niacin might be effective in reducing plaque buildup in the arteries. Specifically, studies showed that niacin could raise HDL (“good”) cholesterol, which was believed to protect against heart disease.
However, more recent studies, including an analysis of 35,760 patients from 17 clinical trials, indicate that niacin doesn’t prevent serious heart-related events, such as heart attacks, strokes, or death from heart disease.
Researchers now generally believe that niacin may help control cholesterol for those who can’t take statins—common medications used to lower cholesterol—but it doesn’t reduce the overall risk of cardiovascular disease.
Dr. Hazen explains the so-called “niacin paradox,” which arose from earlier use of niacin for high cholesterol treatment. Although niacin lowers LDL (“bad”) cholesterol, it doesn’t reduce cardiovascular disease risk and, in some cases, may even increase mortality.
If you’re taking niacin to lower your heart disease risk, Dr. Chen recommends checking with your doctor. He stresses not to panic or stop taking your medication without speaking to your healthcare provider first. “It’s too early to recommend avoiding niacin based on these results,” he says. “For now, I suggest holding off on extra niacin supplementation.”
Keatley adds that nutrition science is always evolving. “Large doses of a key vitamin might not be as beneficial as we once thought, so it’s best to get vitamins from food and avoid extremes.”
Dr. Hazen agrees, advising patients to consult their doctors before using over-the-counter supplements and to focus on a diet rich in fruits and vegetables while limiting excess carbs.
Keep in mind that dietary supplements are meant to complement the diet, not treat or prevent diseases. Be cautious when using them if you’re pregnant, nursing, or giving them to children unless recommended by a healthcare provider.