Heart attack patients who are already taking the right medicines to prevent future problems get no added benefit from taking fish oil capsules, a large study in Germany finds.
The study tested a 1-gram daily dose of a prescription version of highly purified omega-3 fatty acid — the "good fat" contained in certain oily fish that is thought to help the heart.
Researchers led by Dr. Jochen Senges of the University of Heidelberg gave fish oil or dummy capsules to more than 3,800 people who had suffered a heart attack in the previous two weeks. About 90 percent were already receiving all the medicines recommended to prevent a second attack, including aspirin, anti-clotting and cholesterol drugs.
After a year, it made no difference whether these patients took fish oil or dummy capsules. In both groups, fewer than 2 percent had suffered sudden cardiac death, 4 percent had another heart attack, and fewer than 2 percent had suffered a stroke.
If recent heart attack patients are already getting good care, "there is almost nothing you can do better on top of this" to further lower risk, Senges said. He presented the results Monday at an American College of Cardiology conference.
The research doesn't mean that fish oil is of no value, and the study didn't address whether it can help prevent heart disease in the first place, doctors said.
The prescription version used in the study, sold as Omacor and Lovaza in the United States and as Zodin in Europe, is a highly purified and standardized form, different from what many consumers buy off the shelf.
Omega-3 fatty acids also are found in wild oily fish such as salmon, tuna, mackerel, sardines and herring. Scientists think it raises HDL, or good cholesterol, lowers harmful fats called triglycerides and slows the growth of plaque that can clog arteries.
The American Heart Association recommends adults eat fish at least twice a week, said Alice Lichtenstein, a Tufts University nutrition professor and Heart Association spokeswoman. For people with heart disease, the association advises 1 gram of omega-3 a day.
"A modest, 3-ounce cooked salmon has a little more than a gram," she said.
Fish oil capsules are not for children or women who are pregnant or nursing, because the pills pose a bleeding risk. Taking more than 3 grams a day from supplements should only be done under a doctor's orders, the heart association warns. The capsules also should be stopped a week or so before surgery because of a risk of bleeding.
The German study shows that "we need to be a little more cautious about the prediction of individual benefit of any nutritional supplements," said Lichtenstein, who had no role in the research.
"We see this pattern — people are so willing to embrace the simple answer," as if it's possible "to crack a capsule over a hot fudge sundae" and undo the harm of harmful diets and lack of exercise, she said.
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