Study questions fish oil benefit before heart attack

Fish oil supplements did not prevent heart problems in people who hadn't had a heart attack yet, in a large long-term study from Italy.

The study – a gold-standard randomized, controlled trial– tested the effect of omega-3 fatty acids, which are found in oily fish such as tuna or sardines. Patients in the study had risk factors for heart disease, such as high blood pressure, high cholesterol, a history of smoking or narrowed arteries. But patients who had a heart attack in the past weren't allowed to enroll.

Five years after the study began, 11.7 percent of the 6,244 patients taking a capsule containing one gram of fish oil daily had died or been hospitalized for heart problems, compared to 11.9 percent for the 6,269 volunteers who instead received one gram of olive oil every day as a placebo. The result, reported in the New England Journal

of Medicine on Wednesday, is in sharp contrast to other research suggesting that omega-3 fatty acids can help those who have survived a heart attack or suffer from heart failure.

For people who haven't had a heart attack, though, the new findings "provide no evidence of the usefulness of (omega)-3 fatty acids for preventing cardiovascular death or disease," according to the research team, led by Dr. Maria Carla Roncaglioni of the Mario Negri Institute for Pharmacological Research in Milan.

She told Reuters Health in an email that the finding argues against the use of fish oil supplements, at least among Italians, who are already exposed to the Mediterranean diet. "There is no reason to prescribe fish oil supplementation unless they have a heart attack," she said.

The researchers did see a reduction in hospital admissions for heart failure and a preventive effect in women, but "both may be due to chance, although they are consistent with two findings from other studies," the researchers said.