Olive oil supplements may protect arteries from the effects of air pollution, research has shown.

Taking three-gram supplements every day for a month helped to keep the blood vessels of volunteers functioning healthily after they inhaled air containing fine pollutant particles.

Those not given the supplements suffered effects that meant their arteries were not dilating properly to assist blood flow.

Lead scientist Haiyan Tong, from the United States Environmental Protection Agency, said: “Our study suggests that use of olive oil supplements may protect against the adverse vascular effects of exposure to air pollution particles.

Exposure to airborne pollutant particles can lead to endothelial dysfunction, which results in the endothelium, or inner lining, of blood vessels ceasing to function properly. The condition is a risk factor for cardiovascular events such as heart attacks and strokes, and the build-up of clogging deposits on artery walls.

For the study, 42 healthy adults were split into two groups, half of whom received olive oil supplements for four weeks before being exposed to pollutant particles for two hours.

The scientists also found that levels of a protein involved in the breakdown of blood clots increased by more than 11 per cent in the olive oil group after pollutant exposure, and this effect persisted for up to 20 hours. Taking fish oil instead of olive oil supplements had no effect on either endothelial function or blood clot breakdown.