January 16, 2001 CHICAGO (AP) - A study of nearly 80,000 American women adds to evidence that eating fish may be healthful, suggesting that even modest amounts can significantly reduce the risk for the most common type of stroke.
While much of the previous research has focused on fish and heart disease, the new study is one of the few to examine the impact on stroke risk and to differentiate types of strokes, said author Dr. Kathryn M. Rexrode of Brigham and Women's Hospital in Boston who is an instructor at Harvard Medical School.
Omega-3 fatty acids, found in most fish, have been shown to lower levels of blood fats linked to cardiovascular disease and to help keep blood from clotting. The fats are especially plentiful in dark, oily fish such as mackerel, salmon and sardines.
Mounting evidence about fish-linked cardiovascular benefits led the American Heart Association to include eating two servings of fish a week in its updated dietary recommendations last fall.
The new study supports the recommendation, said AHA spokeswoman Alice H. Lichtenstein, a Tufts University nutrition professor.
The findings appear in Wednesday's Journal of the American Medical Association.
In the study, eating fish was linked to reductions in the risk for ischemic strokes, which are clot-related and account for about 83 percent of all strokes in the United States.
Women who ate about 4 ounces (110 grams) of fish two to four times weekly cut their risk of ischemic stroke by 48 percent. Though slightly higher risk reductions were found in women who ate fish five or more times weekly, there were relatively few women in that group. Risk reductions, though not statistically significant, were also found even in those who ate fish once a week or less.
Some researchers have suggested that eating large amounts of fish might increase the risk of hemorrhagic strokes, which occur when a blood vessel in the brain ruptures and bleeds, and which account for about one-fifth of all strokes. But the new data found that a regular diet of fish neither increased nor decreased the risk for this type of stroke.
The authors examined about 14 years of data on 79,839 participants in the Nurses' Health Study. Subjects were women aged 34 to 59 in 1980. There were 574 strokes in the ensuing 14 years.
The authors took into account the women's age and whether they smoked, factors that could affect stroke risk.
But other factors, such as high blood pressure, were not included. The findings thus "don't exclude the fact that maybe there's a hidden association" that might explain the results, said Dr. Lawrence M. Brass, a Yale University neurology professor and spokesman for the National Stroke Association.
Copyright 2001 The Associated Press. All rights reserved.
