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.

Will Aspirin Prevent Your First Heart Attack?

Aspirin does prevent heart attacks and stroke. However, aspirin also increases your risk of severe stomach bleeding. The chances of preventing a heart attack and experiencing a dangerous stomach bleed is about equal. So, the benefit of aspirin for heart attack or stroke is questionable.

The major reason to give aspirin is to prevent heart attacks and strokes, and in healthy people this benefit is outweighed by the risk of bleeding. Aspirin is not the same as statins, which are known to reduce mortality in primary prevention. Aspirin doesn’t affect atherosclerosis; it modifies plaque rupture, which is the final step. That is why it works better in patients with established heart disease.

But, if you’ve suffered a heart attack or stroke before, or are taking medications for diabetes, aspirin’s positive effect on heart health is may be greater than it’s negative effect on stomach health.

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.