High levels of the essential B vitamin niacin may increase your risk of heart disease by causing inflammation and damaging blood vessels, according to a new study.

The report, published Monday in Nature Medicine, reveals previously unknown risks from consuming too much vitamins in many foods, including meat, fish, nuts, fortified cereals and bread.

The recommended intake of niacin is 16 milligrams per day for men and 14 milligrams per day for non-pregnant women.

About 1 in 4 Americans consumes more than the recommended level of niacin, said the study’s lead author, director of cardiovascular and metabolic sciences at the Lerner Institute at the Cleveland Clinic, and director of Heart Disease Prevention Cardiology. said Dr. Stanley Hazen, co-chair of the Department of Science. Vascular Thoracic Research Institute.

Researchers currently don’t know where to draw the line between healthy and unhealthy amounts of niacin, but that could be determined in future studies.

“Now that we have reason to believe that excessive intake of niacin may lead to an increased risk of developing cardiovascular disease, the general public should avoid niacin supplements,” Hazen said.

Hazen said niacin has been added to flour, grains and cereals since the 1940s, after scientists discovered that very low levels of the nutrient could cause a potentially fatal condition called pellagra. Niacin has been fortified, and Americans now consume large amounts of niacin in their diets.

Before the development of cholesterol-lowering statins, niacin supplements were once prescribed by doctors to improve cholesterol levels.

To explore unknown risk factors for cardiovascular disease, Hazen et al. conducted a multipart study that included analysis of fasting blood samples from 1,162 patients who visited a cardiology center for heart disease evaluation. designed the study. Researchers were looking for common markers or signs in patients’ blood that could reveal new risk factors.

Research has discovered a substance in some blood samples that is only produced when there is an excess of niacin.

The findings led to two additional “validation” studies that included data from a total of 3,163 adults with or suspected of having heart disease. Two studies, one in the United States and one in Europe, showed that the niacin breakdown product 4PY predicted participants’ future risk of heart attack, stroke, and death.

The final part of the study involved experiments on mice. Injecting rodents with 4PY increased inflammation within blood vessels.

Dr. Robert Rosenson, director of metabolism and lipids at Mount Sinai Health System in New York City, called the results “fascinating” and “important.”

The newly detected pathway to heart disease could lead to the discovery of drugs that can reduce inflammation in blood vessels and reduce the likelihood of serious cardiovascular events, he added.

Rosenson hopes the food industry will take notice and “stop using so much niacin in products like bread.” This is a case where too much of a good thing can be bad. ”

Rosenson, who was not involved in the Cleveland Clinic study, said the new information could influence dietary recommendations for niacin.

Scientists have known for decades that a person’s cholesterol levels can be a major cause of heart disease, said Dr. Amanda Dolan, assistant professor of cardiovascular medicine at Vanderbilt University Medical Center. .

Dolan said that even if a patient’s cholesterol levels are lowered, some people are still at high risk of heart attack or stroke, and a 2017 trial suggested the increased risk may be related to inflammation in blood vessels. He added that it was done.

Dolan was surprised to learn that niacin may be involved in increasing the risk of heart disease.

“I don’t think anyone could have predicted that niacin would promote inflammation,” she says. “This is a powerful study because it combines a variety of techniques, including clinical data, genetic data, and mouse data.”

find something new This pathway may allow future researchers to find ways to reduce inflammation in blood vessels, Dolan said.

“It’s very exciting and promising,” she said.