Key points from article :
A new study at the Cleveland Clinic found people with high levels of niacin (vitamin B3) in their blood may be more likely to have heart attacks or strokes.
This link could be because too much niacin inflames blood vessels, a major contributor to heart disease.
The research looked at people in the US and Europe, and it's unclear if the results apply to other groups.
High niacin levels can come from fortified foods or supplements, which are popular due to potential anti-aging benefits.
Doctors used to prescribe high-dose niacin for heart health, but this study suggests otherwise.
More research is needed to confirm these findings and understand if they apply to everyone.
The findings are published in the journal Nature Medicine.
