Selenium is of critical importance to human health.  It is involved in a number of bodily functions including thyroid hormone metabolism, antioxidant defense systems and immune function.  Evidence seems to suggest that there is a strong inverse relationship between selenium intake and the risk for cancer.  The speculation is that this is due to selenium’s role in DNA repair.   Finally, there is epidemiological evidence that selenium intake may be related to a reduced risk of coronary artery disease.  In areas of the country with a high level of selenium in the soil there seems to be a lower incidence of this disease.