A Fish a Day Keeps Heart Woes at Bay
Heart association revises its omega-3 fatty acids guidelines
MONDAY, Nov. 18, 2002 (HealthDayNews) -- The American Heart Association is boosting its recommendations about omega-3 fatty acids, telling people with known heart disease that getting enough of them, either in the diet or by taking supplements, can be life-saving.
People with documented heart disease are best off if they get 1 gram a day of two omega-3 fatty acids, eicosapentaenoic and docosehexaenoic acids, which are plentiful in such fish as mackerel, lake trout, herring, sardines, albacore, tuna and salmon, say new guidelines published today in the association's journal Circulation.
A third, less-potent kind, alpha-linoleic acid, found in such plants as soybeans, canola, walnuts and flaxseed, is also recommended.
The association's last guidelines, published in 2000, recommended at least two servings of oily fish each week both for healthy people and those with known heart disease.
The recommendation for people without heart disease remains unchanged.
But studies showing that omega-3 fatty acid consumption reduces cardiac deaths led to the change for people with known heart disease, says William S. Harris, professor of medicine at the University of Missouri, and a member of the committee that drew up the revised guidelines.
"New trials have been reported that finally broke the camel's back," Harris says. "The last report showed that giving 0.85 grams of omega-3 fatty acids to people who survived heart attacks caused a 20 percent reduction in overall mortality over three-and-a-half years. One of the big contributors to that reduction was a 45 percent decrease in sudden cardiac deaths."
The best way to get the recommended intake of the fatty acids for those with known heart disease is by eating oily fish every day, Harris says. People who find such fish distasteful can turn to dietary supplements -- but only after they talk to their physicians about the supplements they plan to take, he says.
"There's still a concern about the quality of product that's out there," Harris says. "There are no standard measures of omega-3 fatty acid content in supplements. Many of them are very good, but we can't make recommendations about specific products, so we're dumping the issue to the physicians."
Some people --those with elevated blood triglyceride levels, for instance -- may need 2 to 4 grams a day of the omega-3 fatty acids, the guidelines say. But anyone taking at least 3 grams daily should do so only under a doctor's supervision, because high intakes might cause excessive bleeding.
The two servings a week of oily fish recommended for people without heart disease works out to "in the neighborhood of 300 to 400 milligrams a day," Harris says. The epidemiological evidence for that recommendation is not as strong as might be desired, he adds, but there is a feeling that it will do most people good.
There are exceptions to the two-serving recommendation. Children, pregnant women and nursing mothers are advised to avoid fish that the U.S. Food and Drug Administration has listed as posing potential mercury hazards: king mackerel, tilefish, swordfish and shark.
Fish oil researchers like Harris -- he has been at it for more than 20 years -- are still studying the mechanisms by which omega-3 fatty acids reduce coronary risk. But studies have shown they reduce the likelihood of blood clots, lower blood pressure, decrease blood levels of harmful fats and interfere with the growth of artery-blocking plaque deposits.
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