Selenium, a trace element, is a natural antioxidant that your body needs to support its overall health. It works to scavenge free radicals that may cause your cell membranes and DNA harm. It boosts the body’s natural defenses and supports normal cellular functioning, which may lessen signs of aging. When combined with vitamin E, selenium may have several additional benefits: It can support some of the cells that are responsible for producing energy, and it may promote fertility and growth. Selenium also supports healthy blood flow because it is essential to the production of prostaglandins. It is involved in thyroid hormone synthesis and immune system functioning.