Think of fish as a good thing - particularly if you're a woman looking to reduce your risk of stroke.
The more fish women eat, the greater the benefit, says a new study.
"We found that women who ate fish just one to three times a month had a seven percent lower risk of stroke than those who ate it only once a month," says study author Dr Kathryn M. Rexrode, an internist at Brigham and Women's Hospital in Boston.
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"Increase your fish intake to once a week, and stroke risk could go down by 22 percent," she says. "Two to four times a week reduces risk to 27 percent, and eating fish five times a week or more brings down the risk of stroke by up to 52 percent." Findings will appear in this week's Journal of the American Medical Association.
Experts say the likely reason fish protects women is the concentration of omega-3 fatty acids, nutrients that prevent the formation of clots, mostly by making blood less "sticky." This, in turn, reduces the risk of ischemic stroke, which is caused by blood clots that form either in the brain (leading to a thrombotic stroke) or elsewhere in the body and then travel to the brain (causing an embolic stroke).
Epidemiologist Gail Frank, a spokeswoman for the American Dietetic Association, says the new findings enforce what dietary experts long have believed.
"We have known for several decades that fish, by the nature of the fatty acid composition, when eaten more often, can alter lipids and, potentially, the clotting mechanism as well as plaque formation. Over time, it can change a little bit of the chemistry of the body," Frank says.
"This study is important because there has been a deficit of research to look at women," she says. "It's an important message for women to now know something positive they can do to reduce their risk of stroke."
In addition to reinforcing the preventive link between omega-3 acids and ischemic stroke, the new study finds fish acids do not contribute to hemorrhagic stroke, which occurs when a blood vessel inside the brain ruptures or "leaks."
Normally, factors that decrease the risk of blood clotting, including omega-3, are thought to increase the risk of a "leaky" hemorrhagic stroke, but the latest study shows that's not the case for consumption of fish, the researchers say.
"Our research showed that eating fish does not have an adverse effect on hemorrhagic stroke," Rexrode says. "It doesn't increase the risk, which is something we did not know for certain before."
The researchers also found that fish is not likely to further reduce the risk of clot formation for people already taking aspirin to reduce their risk of stroke.
"Platelet aggregation, or the formation of blood clots, is a kind of all-or-nothing mechanism. You either turn it on or you turn it off," Rexrode says. In other words, once the biological switch is thrown to turn off platelet aggregation, which is something aspirin does, then additional attempts to do the same thing, such as eating fish, do not increase the effects, she says.
"If they work on the same mechanism, you're not going to see any added benefits to eating fish among aspirin users, because it's already being taken care of by aspirin, and aspirin is more potent in blocking this effect," Rexrode says.
But this does not mean that taking aspirin precludes the need to eat fish - or the other way around, she says.
"Studies have shown fish may have other important health benefits, so adding two to four servings per week to your diet is still important, even if you are already taking aspirin," she says.
Likewise, she says, aspirin still may be an important and necessary treatment, even if you're eating fish.
What to do
While adding more fish to your diet appears healthful, it's important to note that not all fish are alike. Light-meat fish, like flounder or whiting, have only about 0.5 grams of omega-3 fatty acid per 4-ounce serving, while dark-meat fish, such as salmon, sardines, mackerel or bluefish, have roughly 1.5 grams of the protective fatty acid in the same amount of fish. - (HealthDayNews)
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