There are several possible causes of male impotence, and the risk increases with age. Oxidative stress appears to play a role, as this condition contributes to local atherosclerosis, which restricts blood flow to the penis. However, consuming a variety of antioxidants - such as selenium, zinc, vitamins A, C, and E, as well as various carotenoids - may help reduce the risk of impotence, according to a U.S. population study published in Scientific Reports.