Excess levels of vitamin B3 linked with increased heart disease risk

Image of a variety of bread, cereals, and grain in wooden bowls on a rustic wood table

New research suggests that high levels of niacin, also known as vitamin B3, may increase cardiovascular disease risk.

Niacin, an essential micronutrient found in fortified flour and cereal, is known for its LDL cholesterol-lowering effects. Yet despite this positive impact on heart health, CVD risk still remains high. To untangle this complex relationship, NHLBI-funded researchers collected blood samples from over 1,000 individuals to screen for circulating small molecules whose levels could predict CVD event risks independent of traditional risk factors. 

They discovered two breakdown products from excess niacin intake, known as 2PY and 4PY, that were significantly associated with increased risk of heart attack, stroke, and other adverse cardiac events. In follow up mouse studies, the researchers also showed that 4PY can directly trigger vascular inflammation leading to blood vessel damage and atherosclerosis over time.

From 2017-2020 total niacin consumption in the U.S., through a mix of natural food sources, fortified foods, and supplementation, averaged 48 mg/d – more than triple the Recommended Daily Allowance.

“The present studies raise the question of whether a continued mandate of flour and cereal fortification with niacin is warranted,” said the study authors. 

The research is published in Nature Medicine.