This antioxidant enzyme protects cell membranes and red blood cells from oxidative damage by free radicals. The highest concentrations of selenium are found in the liver, heart, spleen, and kidneys. About 90 percent of the ingested selenium IS absorbed.
Excess selenium is excreted through the urine and lungs.
Selenium is similar to sulfur in its physical properties. The mineral is a natural antioxidant that protects the cells against the oxidative damage of free radicals. Low selenium levels are associated with an increased risk for cancer in humans. Selenium supplementation might be useful in the prevention of cancer especially that of the respiratory and gastrointestinal tract. Selenium benefits all aspects of the immune system including the development and function of white blood cells.