smogA diet high in plant flavonoids may help people vulnerable to heart risk when they inhale fine particles in smoke and hazy polluted air, according to research presented at the American Heart Association’s Scientific Sessions 2014.

Flavonoids are anti-inflammatory nutrients found in vegetables, fruits, chocolate and wine.

During an 11-year follow-up of 573 elderly men, heart rate variability — a predictor of heart attacks and heart-related death — worsened when average fine particle levels rose for 48 hours. The association was exacerbated in men with a stronger suppressive regulation of a protein, called toll-like receptor 2, which detects foreign substances and pass on signals to the immune system.

However, the association between heart rate variability and pollution levels and the immune response were far weaker in men who consumed high levels of flavonoids in their diets.

Flavonoids may help protect against pollution-related heart risk by helping regulate the body’s immune system response, researchers said.