Researchers plan to conduct a large clinical trial designed to evaluate the impact of vitamin D and omega 3 in reducing the risk of cancer and heart disease among people with no prior history of such ailments.

The National Institutes of Health will fund this $20 million study—dubbed the Vitamin D and Omega 3 Trial (VITAL). Scientists at Harvard Medical School and the Brigham and Women’s Hospital in Boston, MA, intend to evaluate 20,000 U.S men and women over a period of five years.

Women aged 65 or older and men aged 60 or older will be assigned to one of four groups: daily vitamin D and fish oil; daily vitamin D and fish oil placebo; daily vitamin D placebo and fish oil; or daily vitamin D placebo and fish oil placebo.

Doses to be administered are estimated at 2000 IU of vitamin D and about 1 gram of omega 3 fatty acids from fish oil.

The Associated Press reported that Pharmavite, Northridge, CA, is providing the vitamin D supplements and Ocean Nutrition Canada, Dartmouth, Nova Scotia, is supplying the fish oil. Recruitment for the study will begin in January.