WEDNESDAY, May 8 (HealthDay News) -- Although previous research has shown that omega-3 fatty acids may help those who have already had a heart attack or suffer from heart failure, a new study finds that the supplements do little to prevent cardiac trouble in people who have risk factors for heart disease.

Italian researchers reported that omega-3 fatty acid supplements did not reduce death from heart disease or heart attacks or strokes in this vulnerable group.

"Contrary to the expectations, adding supplemental omega-3 fatty acids does not have any specific advantage in a population that is considered at high risk of cardiovascular disease," said lead researcher Dr. Gianni Tognoni, from the Istituto di Ricerche Farmacologiche in Milan.

Tognoni said omega-3 fatty acids do seem to help prevent abnormal heart rhythms following a heart attack or heart failure. There appears, however, to be no value in taking the supplements to prevent heart disease, he added.

"Don't trust too much on drugs that attempt to mimic lifestyle [changes]," Tognoni said.

It's the usual recommendations that really ward off heart disease, he said, including not smoking, eating a healthy diet and getting exercise.

Study co-author Dr. Maria Carla Roncaglioni, head of the Laboratory of General Practice Research at the Istituto di Ricerche Farmacologiche Mario Negri, added that "there is no need to add a long-term preventive treatment with omega-3 fatty acids in people with cardiovascular risk factors [that are controlled with] evidence-based treatments and healthy lifestyle -- particularly with regard to dietary habits."

The report was published in the May 9 issue of the New England Journal of Medicine.

One expert said the evidence on omega-3 fatty acids has been mixed.

"Some prior clinical trials have shown a beneficial effect of omega-3 fatty acids derived from fish -- also known as fish oil or n-3 polyunsaturated fatty acids -- in patients with established cardiovascular disease or to prevent cardiovascular events in the general adult population," said Dr. Gregg Fonarow, a professor of cardiology at the University of California, Los Angeles. "However, other clinical trials have shown no benefit."

"Based on the totality of current evidence, the pendulum appears to be shifting away from omega-3 fatty acid supplementation providing significant cardiovascular event reduction," Fonarow said.

To see if omega-3 fatty acids had a beneficial effect, the Italian researchers randomly assigned more than 12,000 people who had risk factors for heart disease to either omega-3 fatty acid supplements or a placebo.

During five years of follow-up, more than 1,400 people died from heart disease or had a heart attack or stroke, the researchers found. Among those taking omega-3 fatty acid supplements, 11.7 percent had one of these outcomes, compared to 11.9 percent of those taking a placebo.

More information

For more on heart disease, visit the American Heart Association.