August 30, 2010
No Benefit For Heart Attack Survivors From Omega-3 Margarines
A new study has shown that patients with a history of heart attacks who eat omega-3 enriched margarine in addition to their standard prescription drugs appear to have no difference in their chances of having a repeat attack than using drugs alone.
A 40-month study of more than 4,800 patients between 60 and 80 years old showed that receiving low doses of omega-3 fatty acids in margarine did not greatly reduce rates of serious heart attacks and other cardiovascular events, researchers said on Sunday.
The findings do not mean that getting more of the essential nutrient has no value. Several studies have shown evidence that the omega-3 fatty acids, mostly those from fish oil, reduce heart disease.
Omega-3 fatty acids are thought to help reduce the risk of abnormal heartbeat, slow the growth of plaque that clogs arteries and lower harmful triglycerides. Omega-3 has been added to several foods in recent years, including margarine and eggs. Some other foods also highlight the content of omega-3 such as tuna fish.
There are two types of omega-3 that come from wild oily fish such as salmon and tuna. A third type comes from plants such as walnuts, flaxseed, soybeans and canola oil.
Health officials generally recommend that people eat one or two servings of fish a week, Daan Kromhout of Wageningen University in the Netherlands, told the Associated Press (AP).
"The results of this trial do not change that," he said, noting that there were no harmful side effects. "It's still a good thing to eat fish once or twice a week."
Participants in the study were taking the best possible medicines to prevent future heart troubles, and that could be why adding a low-dose of omega-3 offered no extra protection, researchers said.
Kromhout told the European Society of Cardiology the lack of efficiency might reflect the good background drug treatment patients were receiving, with 85 percent on cholesterol-lowering drugs, as well as blood pressure and blood-thinning pills.
For the study, Kromhout and colleagues recruited 4,837 heart attack patients in the Netherlands who were 60 to 80 years old. They were randomly assigned to eat one of four kinds of margarine -- regular margarine or margarine with added omega-3s derived from fish, plants or both.
Kromhout said they used margarine because it was easier than fish oil supplements to make all versions look and taste identical.
Patients ate, on average, about 4 teaspoons of margarine a day. During the 40 months the participants were followed, 671 patients -- 14 percent -- had a heart problem or died. There was no difference between the groups, no matter what type of margarine they used.
Dr. Stephen Kopecky, a cardiologist at the Mayo Clinic in Rochester, Minnesota, said it may have been a matter of too little, too late -- the doses were small and the patients were enrolled, on average, 4 years after their initial heart attack.
"If you wait too long, sometimes you miss that window to benefit them," Kopecky told the AP. He said he tells his heart patients to take 1,000 milligrams of fish oil every day.
Since the Dutch study was in heart attack survivors, Lichtenstein said it still isn't known whether omega-3s can protect a first heart attack or help those who do not get great care.
Despite the overall negative results, researchers found there was a reduction in repeat heart attacks and other cardiovascular events in women who took ALA margarine, although this was not statistically significant. Diabetes patients also showed a possible benefit.
Unilever, the maker of Flora and I Can't Believe It's Not Butter, which both contain omega-3, said the lack of benefit seen with EPA and DHA was surprising, considering the weight of evidence published to date.
"The results indicate that more investigation is required into the efficacy of vegetable omega 3, but do not question the current authoritative dietary recommendations and advices for omega 3 intakes on which our products are based," the company said in a statement.
The Netherlands Heart Foundation, the National Institutes of Health, and Unilever supported the study, which is published in the New England Journal of Medicine.
On the Net:
- Wageningen University
- European Society of Cardiology
- New England Journal of Medicine
- Image Courtesy Wikipedia