Vitamin D3 supplementation can effectively remedy the current epidemic of vitamin D deficiency, especially within the African-American population and the elderly of any ethnicity. Racial disparities in prostate cancer outcomes mirror racial differences in vitamin D levels, as African American men exhibit a high prevalence of hypovitaminosis D, raising the possibility that long-term vitamin D deficiency may contribute to the progression from subclinical prostate cancer to clinical disease, especially among African American men. Therefore, eliminating racial disparities in circulating levels of vitamin D could have important implications for reducing disparities in prostate cancer outcomes. The efficacy of this approach has been clearly demonstrated during the course of clinical trials (conducted as a PI under FDA IND 77,839), employing robust vitamin D3 supplementation in patients diagnosed with early-stage, low-risk prostate cancer. Dr. Gattoni-Celli and others recently reported that daily supplementation with 4000 IU of vitamin D3 for one year is safe and is associated with a decrease in the number of positive cores at repeat biopsy; this regimen “erases” any vitamin D deficiency or insufficiency in all the patients enrolled in the study. Furthermore, research has shown that supplementation eliminates racial disparities in serum levels of 25(OH)D between African American and white men. Additionally, separate preclinical studies have demonstrated that a vitamin D-rich diet in an animal model of Alzheimer’s disease results in a significant decrease in the size and number of amyloid plaques in the brain of supplemented mice, compared to controls.