Stroke protection: A little fish helps

Eating as little as one serving of fish per month may reduce a man’s risk of certain strokes by 40 percent, a new study finds. Indeed, eating fish more frequently offers no additional benefit, the data suggest.

More than 80 percent of strokes are of the ischemic variety, which means they’re caused by blocked blood vessels in the brain. Most of the blockages are caused by clots. Ruptured blood vessels account for the rest, which are called hemorrhagic strokes.

In the new study, Ka He and his colleagues at the Harvard School of Public Health in Boston documented 377 cases of ischemic stroke and 106 cases of hemorrhagic stroke during a 12-year follow-up of nearly 44,000 men participating in a survey of male health professionals. The Harvard researchers correlated the incidence of these different types of stroke with dietary data collected from the volunteers.

This analysis revealed that men who ate fish monthly, including shellfish, suffered dramatically fewer ischemic strokes. The rate of hemorrhagic stroke wasn’t different in the fish versus nonfish eaters. The findings appear in the Dec. 25, 2002 Journal of the American Medical Association.

Although other studies have also found evidence that eating fish protects against stroke, most had been too small to investigate effects by stroke type.

What surprised He most was how little fish it took to impart protection against ischemic stroke. He says the message for men is clear: “Incorporate fish, whether it’s lobster, canned tuna, or salmon, into your diet.”


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Janet Raloff is the Editor, Digital of Science News Explores, a daily online magazine for middle school students. She started at Science News in 1977 as the environment and policy writer, specializing in toxicology. To her never-ending surprise, her daughter became a toxicologist.

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