A trace element found in foods such as seafood, fresh garlic, mushrooms, wheat germ and some whole grains, selenium helps increase the effectiveness of vitamin E and is an antioxidant. Insufficient levels of it have been linked to an increased risk of prostate cancer. Selenium also protects against toxic pollutants for sexual reproduction. It's used in some skincare preparations to protect skin from free radical damage. It's also found in hair, skin and nail combination supplements.