Penn State Milton S. Hershey Medical Center researchers are trying to compare the effects of two different forms of selenium (selenium yeast and selenomethionine) on blood selenium levels and biomarkers of oxidative stress as primary endpoints. One in six men are at risk of getting prostate cancer in their lifetime. Participants will be asked to take over-the-counter selenium yeast supplements and selenomethionine or a placebo for nine out of twelve months.