You’re referring to a large study from Italy. Researchers there found no benefit to taking daily supplements of omega-3 fatty acids (fish oil) for patients whose average age on joining the study was 64 and who had risk factors for cardiovascular disease but hadn’t had heart attacks. After five years, the study showed that 11.7 percent of the 6,244 patients taking a supplement providing one gram of fish oil had died or had been hospitalized for heart problems compared to 11.9 percent of 6,269 patients who took a placebo providing one gram of olive oil. This was a double-blind, randomly controlled trial, meaning that neither the researchers nor the participants knew who was taking the fish oil supplement and who received the placebo.
Omega-3 fatty acids are essential fats we need for optimum health. Unfortunately, most Americans don’t get adequate amounts of omega-3s in their diets, and as a result are more likely to develop cardiovascular disease, cancer, inflammatory disorders, and mental and emotional problems. Foods containing these fatty acids include oily, cold water fish, such as salmon, mackerel, herring, and sardines; walnuts; freshly ground flaxseeds and hemp seeds – and the oils extracted from them; unprocessed soy and canola oils; and eggs fortified with omega-3s.
We know from previous studies that taking supplements of omega-3 fatty acids significantly reduces deaths from heart disease in patients who already have had heart attacks and that taking omega-3s also significantly reduced deaths and hospital admissions among patients with heart failure who also were receiving standard medical treatment for this disorder.
While the benefits of omega-3 supplementation for healthy people aren’t certain, for those who already have heart disease, they look pretty good. And we know that populations that eat fish regularly live longer and have less chronic disease than those that do not. (We don’t know if this is because fish displaces meat or because it has positive attributes of its own.)
Despite the findings of the Italian study and the fact that we don’t yet have incontrovertible proof of the benefits of omega 3s for heart disease prevention, most health experts in the United States recommend increasing consumption of oily fish or taking supplemental fish oil or both. My longstanding recommendation is to consume two to three servings of fish per week as well as two to three grams daily of a quality fish oil supplement. Look for one that is "molecularly distilled" or otherwise guaranteed to be free of mercury, PCBs, and other contaminants.
Given the fact that you have had a heart attack, I urge you to continue taking your omega-3 supplements and to include oily, cold water fish in your diet.
Andrew Weil, M.D.