Even if kids eat a diet filled with fruits and vegetables, their bodies might be robbed of those beneficial antioxidants if they’re exposed to cigarette smoke. A study by the University of Rochester Medical Center that included more than two thousand kids and teenagers find those who breathe in the most secondhand smoke have lower levels of antioxidants in their bodies.

Experts say antioxidants help protect the body against free redicals, which can damage cells. Researchers say it’s too early to tell whether kids who are around cigarette smoke need supplements to boost their antioxidant supply. But they say giving them plenty of fruits and vegetables is a good idea regardless.