High levels of niacin linked to heart disease, new research suggests

High levels of niacin, an essential B vitamin, may raise the risk of heart disease by triggering inflammation and damaging blood vessels, according to new research.

The report, published Monday in Nature Medicine, revealed a previously unknown risk from excessive amounts of the vitamin, which is found in many foods, including meat, fish, nuts, and fortified cereals and breads.

The recommended daily allowance of niacin for men is 16 milligrams per day and for women who are not pregnant is 14 milligrams per day.

About 1 in 4 Americans has higher than the recommended level of niacin, said the study’s senior author, Dr. Stanley Hazen, 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 currently don’t know where to draw the line between healthy and unhealthy amounts of niacin, although that may be determined with future research.

"The average person should avoid niacin supplements now that we have reason to believe that taking too much niacin can potentially lead to an increased risk of developing cardiovascular disease,” Hazen said.

Currently, Americans get plenty of niacin from their diet since flour, grains and cereals have been fortified with niacin since the 1940s after scientists discovered that very low levels of the nutrient could lead to a potentially fatal condition called pellagra, Hazen said.

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

To search for unknown risk factors for cardiovascular disease, Hazen and his colleagues designed a multipart study that included