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Because of a lapse in government funding, the information on this website may not be up to date, transactions submitted via the website may not be processed, and the agency may not be able to respond to inquiries until appropriations are enacted.

The NIH Clinical Center (the research hospital of NIH) is open. For more details about its operating status, please visit cc.nih.gov.

Updates regarding government operating status and resumption of normal operations can be found at opm.gov.

Vitamin D and Omega-3 Trial (VITAL)

Trial Status: closed to accrual

The VITamin D and OmegA-3 TriaL (VITAL) is a randomized clinical trial in 25,871 U.S. men and women investigating 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. The 5-year intervention phase (study pill-taking, median 5.3 years) has ended; post-intervention observational follow-up of study participants is ongoing.