Can too much of a vitamin affect your heart health? A recent study found that taking excessive quantities of the niacin could raise the risk of heart disease.

Vitamin B3 or niacin has many functions, including the conversion of nutrients into energy, synthesizing cholesterol and fats, creation and repair of DNA, and antioxidant effects. Additionally, it plays the role of a coenzyme to over 400 enzymes that facilitate various reactions.

Niacin is present naturally in various foods such as meat, fish, and nuts, and in fortified cereals, and breads. In cases where individuals are unable to manage their cholesterol levels effectively through statins, diet, and exercise, a niacin supplement may be prescribed as part of the treatment for cholesterol.

The recommended daily intake of niacin is 16 milligrams (mg) a day for male adults and for adult women who are not pregnant, 14 mg a day.

According to Dr. Stanley Hazen, a senior author of a recent study published in Nature Medicine, about 1 in 4 adults in the U.S. have higher than the recommended levels of niacin.

"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.

The findings emerged from a multi-part study, where researchers initially examined fasting blood samples from 1,162 cardiac patients to identify common markers in the blood that could unveil their risk factors. They then identified substances 2PY and 4PY in some blood samples that were associated with excess niacin.

The researchers observed that the presence of 4PY and 2PY in the participants predicted their future risk of heart attack, stroke, and death. They were associated with an up to twofold increased risk of cardiovascular disease independent of traditional risk factors.

"Niacin, which is fortified in food staples, contributes to NAD [nicotinamide adenine dinucleotide] synthesis and has been shown to provoke increased circulating 2PY and 4PY when present in excess, such as when provided as an over-the-counter supplement or as a pharmacological agent for cholesterol-lowering," the researchers stated.

The results were validated through two additional studies, with data from a combined total of 3,163 adults with either confirmed heart disease or suspected cases.

Subsequently, the researchers conducted a mice study and discovered that the injection of 4PY and 2PY increased inflammation in the blood vessels of the rodents.

However, researchers have yet to establish clear boundaries between healthy and excessive niacin intake, a determination that may come with future studies.