Selenium is a trace element and mineral essential for human life. It is critical to protecting cells from oxidative stress and helping the thyroid produce hormones. It is found in many selenium-rich fruits and vegetables and some animal products. Selenium is a powerful anti-oxidant more potent than Vitamins A, C or E. It is an active immunomodulatory. Like Iodine, Selenium plays an important role in the synthesis of thyroid hormones. Free radical damage causes the cell degeneration we know as aging. Selenium neutralizes the damaging effects of free radicals. One study revealed that selenium levels decline with age and and low levels contribute to cognitive decline in older adults. Data suggests that supplementing with organic (carbon bound) selenium supports mercury excretion. It is clear that there is a relationship between selenium intake and cardiovascular health. As early as 1937, the connection between low selenium levels and instances of heart failure have been clear. Not only is selenium itself important for a healthy heart, it works with other nutrients such as Vitamin E and Beta Carotene to promote normal cholesterol levels. Selenium is crucial for both male and female reproductive health - it enables sperm locomotion and a deficiency can lead to male infertility. Low selenium can also have a negative impact on female fertility and fetal growth. Research has confirmed a trend in which low concentrations of selenium correlated with an in creased risk of certain types of cancer.