About 26,000 people participated in the so-called VITamin D and OmegA-3 Trial (VITAL). The trial — said to be the “largest and most recent to test whether vitamin D or fish oil can effectively prevent cancer or cardiovascular disease" — followed the participants for roughly five years.
By the end, the researchers concluded that Omega-3 fatty acids, or fish oil, “were associated with significant reductions in heart attacks,” according to a press release from The North American Menopause Society (NAMS) regarding the results. The findings will be presented at the organization's annual meeting this month.
“The greatest treatment benefit was seen in people with dietary fish intake below the cohort median of 1.5 servings per week but not in those whose intake was above that level,” the researchers said, noting African Americans, in particular, “appeared to experience the greatest risk reductions.”
Vitamin D, too, was found to have benefits — namely reducing the risk of a cancer-linked death.
More specifically, vitamin D was “associated with a statistically significant reduction in total cancer mortality among those in the trial at least two years,” they wrote.
“The pattern of findings suggests a complex balance of benefits and risks for each intervention,” Dr. JoAnn Manson, the study’s lead author, said in a statement. That said, Manson added, the results “point to the need for additional research to determine which individuals may be most likely to derive a net benefit from these supplements.”