This is a randomized double-blind, placebo-controlled study in which the treatment allocations will be kept sealed until the final statistical evaluation. The design will include the recruitment of 60 healthy subjects (30-79 yr of age) randomized into 3 groups. A total of 48 subjects, 16 per group will be required based upon power calculations and results from a previous clinical trial with selenium. An additional 4 subjects per group will be placed on trial to account for possible attrition or non-compliance. Blood, urine and exfoliated buccal mucosal samples will be obtained from all subjects at baseline. Questionnaire data on usual dietary intake will also be obtained at baseline. Eligible subjects will be required to have not have taken any high dose antioxidant supplements for at least 1 month prior to the study. Subjects will then begin supplementation according to the following schedule: