Fish Oil Supplements Cut Sudden Death Risk
Study finds they reduce chances by half in heart attack victims
MONDAY, April 8, 2002 (HealthDayNews) -- Daily supplements of a fatty acid found in fish oil cuts the risk of sudden death by half in people who have had heart attacks.
Despite this finding from a new Italian study, the American Heart Association says it can't yet recommend these supplements. Even more discouraging, another expert says many cardiologists are not telling patients about this benefit and drug companies are studiously avoiding the subject.
The report comes from a study that enrolled more than 11,000 Italians who survived heart attacks. They all got the usual medical treatment and lifestyle advice. In addition, some took 1 gram a day of a supplement containing n-3 polyunsaturated fatty acids (PUFA), also known as omega-3 fatty acids, the kind found in fish oil. Others took a vitamin E supplement, still others took both, and a control group took neither.
After three months, says a report in tomorrow's issue of Circulation, there was a significant difference in the incidence of sudden death -- 0.5 percent for those taking the PUFA supplement, 0.7 percent for those who weren't. The difference persisted after 42 months -- a 2 percent risk of sudden death for those taking PUFA, 2.7 percent risk for those who did not. The overall death rate was 8.4 percent for PUFA people, 9.8 percent for the others -- again, statistically significant.
"At the end of the study, we realized that there was a significant reduction of total mortality, whereas the reduction of all cardiovascular events was not statistically significant," says Dr. Roberto Marchioli, leader of the study.
The risk of sudden death is highest in the months after a heart attack, Marchioli notes, which is exactly when the fish oil supplement benefit is clearest. That benefit is not related to cholesterol levels or a reduction in blood clots, he says.
"It seems to support the idea that the mechanism of action of the fatty acids is a reduction in arrhythmias," Marchioli says. The current theory is PUFA helps keep the heartbeat normal by regulating the electrical activity of heart muscle cells.
"We know the molecular mechanism by which these fatty acids stabilize the heart electrically," says Dr. Alexander Leaf, professor of clinical medicine at Harvard Medical School and author of an accompanying editorial. Work in his laboratory has shown PUFA makes heart cells resistant to arrhythmias.
The finding needs confirmation, Marchioli says, and Leaf agrees that "we need a few more careful clinical trials of people at risk of sudden death."
The American Heart Association says it does not recommend fish oil supplements and will not recommend them "until there is compelling evidence that they benefit overall cardiovascular health." It does recommend eating plenty of fish.
That's all well and good, says Marchioli, but "not all people like fish, and in addition it is rather difficult to eat fatty fish every day of one's life."
Diet or supplement? "It doesn't make any difference," Leaf says. "But when you are doing a large clinical trial, it is easier to measure compliance when fatty acids are given as a supplement rather than having people eat more fish."
He adds a sour note: "The evidence of benefit is becoming overwhelming, but not enough cardiologists are paying attention. Patients are rarely advised to follow the directions of the heart association."
Worse, drug company advertising will not usually mention fish oil, Leaf says.
"The pharmaceutical industry has no interest in promoting fatty acids," he says. "They can't be patented."
What To Do
"The association recommends consuming two servings of fish twice a week," says an American Heart Association statement. "Fish are a good source of protein without the high saturated fat found in fatty meat products."