Effects of Vitamin D and Marine Omega-3 Fatty Acids on Anemia

The VITamin D and OmegaA-3 TriaL (VITAL; NCT01169259) is a randomized clinical trial in 20,000 U.S. men and women studying whether taking daily dietary supplements of vitamin D3 (2000 IU) or omega-3 fatty acids (Omacor® fish oil, 1 gram) reduces the risk of developing cancer, heart disease, and stroke in people who do not have a prior history of these illnesses. This ancillary study is being conducted among VITAL participants and will study whether vitamin D or fish oil: (A) in the overall VITAL cohort, reduces the number of persons diagnosed with anemia and (B) in a subcohort of 900 participants seen in Boston, effects long-term changes of the proteins in blood in both anemic and non-anemic individuals who provide blood samples at the start of the study and again 2 years later.