Dietary antioxidants offer no protection against the development of coronary heart disease (CHD), suggesting supplements may not do so either, a study suggests.

Evidence about role of diet-derived antioxidants (vitamins E and C and carotenoids) in primary CHD prevention is conflicting, Assistant Professor Raymond Noordam and colleagues from Leiden University, in the Netherlands, note in the Journal of the American College of Cardiology.

Using Mendelian randomisation, the study compared “individuals who had a genetically predicted higher antioxidant level in blood with individuals who had a genetically predicted lower antioxidant level in blood,” Professor Noordam said.

From an analytic sample of more than 768,000 individuals from three large cohorts, including 93,230 CHD cases, “we found no protective effect and therefore conclusive evidence antioxidant levels are not causally related to the risk of coronary artery disease,” he said.