Baked or broiled fish may help reduce the risk of stroke

January 24, 2005

CHICAGO—The consumption of tuna or other broiled or baked fish is associated with a lower risk of stroke in the elderly, while eating fried fish or fish sandwiches is linked to a higher risk, according to an article in the January 24 issue of the Archives of Internal Medicine, one of the JAMA/Archives journals.

"Cardiovascular diseases are the leading cause of death and disability in the elderly, who are the fastest-growing segment of the population," according to background information in the article. Results from studies of fish consumption and stroke risk are inconsistent, and none have focused on the elderly, in whom disease burden may be high. In addition, the effect of fish consumption on cardiovascular disease may depend on the type of fish consumed-broiled or baked fish as compared to fried fish or fish sandwiches.

Dariush Mozaffarian, M.D., M.P.H., from the Harvard School of Public Health, Boston, and colleagues examined the association between different types of fish meals and the risk of stroke in adults aged 65 years and older (average age=72.7 years). Diet was assessed in 4,775 adults in 1989-1990 using a food questionnaire, which included how often, on average, patients consumed broiled or baked fish (including tuna), and fried fish or fish sandwiches. Participants were followed-up for 12 years.

Researchers identified a trend of a 14 percent lower stroke risk with a consumption of broiled or baked fish one to three times per month; this same amount and type of fish consumption was associated with a 15 percent lower risk of ischemic stroke. Eating broiled or baked fish one to four times per week, or five or more times per week was associated with a respective 28 percent and 32 percent lower risk of ischemic stroke. However, fried fish and fish sandwich consumption was associated with a 37 percent higher risk of all types of stroke and a 44 percent higher risk of ischemic stroke. Each serving of fried fish or fish sandwich per week increased the risk of a stroke by ten percent, with 13 percent higher risk for ischemic stroke. Average fish consumption was .7 servings of fried fish/fish sandwich, and 2.2 servings of broiled or baked fish.

"Although the observed associations may reflect dietary habits earlier in life, our findings suggest that diet may influence stroke risk beyond the earlier development of cardiovascular disease in young adulthood and middle age," the authors write. "Our findings also suggest that...preparation methods may be important when considering relationships of fish intake with stroke risk."
Arch Intern Med. 2005;165:200-206.

Editor's Note: The research reported in this article was supported by contracts from the National Heart, Lung, and Blood Institute, U.S. Department of Health and Human Services, Bethesda, Md. Support for Dr. Mozaffarian was provided in part by a National Research Service Award Training Grant in Academic Nutrition at the Harvard School of Public Health, Boston.

For more information, contact JAMA/Archives media relations at 312/464-JAMA (5262) or e-mail mediarelations@jama-archives.org.

Fried Fish Raises Stroke Risk

Broiled or baked reduces it, study finds

By Ed Edelson
HealthDay Reporter

MONDAY, Jan. 24 (HealthDayNews) -- If you're planning to add more fish to your diet to protect your health, make it broiled or baked -- not fried.

Harvard researchers found in a study of more than 4,700 older people that eating fried fish or fish sandwiches was associated with a higher risk of stroke.

Conversely, the study also found a direct relationship between consumption of broiled or baked fish and a reduced incidence of stroke, according to a report in the Jan. 24 issue of the Archives of Internal Medicine.

The link between increased risk and fish sandwiches probably was due to the fact that those sandwiches tended to be fried-fish burgers from fast-food outlets, said Dr. Dariush Mozaffarian, an instructor of medicine at the Channing Laboratory, operated by Harvard Medical School and Brigham and Women's Hospital.

However, the study couldn't determine an exact relationship between fish consumption and stroke risk; other lifestyle factors might influence that risk, Mozaffarian said. For instance, people who tend to eat fast food may not pursue a healthy lifestyle, which includes proper nutrition and exercise.

What is clear from this and other studies is that eating oily fish such as tuna is good for the arteries and the cardiovascular system in general, he said. Data from the same study found a lower risk of atrial fibrillation, a potentially fatal disturbance of heart rhythm, Mozaffarian said.

"The message for a public audience is that intake of tuna fish or other oily fish is good for cardiovascular health," he said. "The second message is that intake of fried fish or fish burgers is unlikely to reduce risk."

Other oily fish that help the heart and arteries include salmon, mackerel, herring and anchovies, Mozaffarian said.

In the study, consumption of broiled or baked fish one to three times a month was associated with a 14 percent reduction in stroke risk. Eating broiled or baked fish one to four times a week was associated with a 28 percent reduction in stroke risk, while the risk was 32 percent lower for people who ate fish in those forms five or more times a week.

But consumption of fried fish or fish sandwiches was associated with a 37 percent higher risk of all kinds of stroke, and a 44 percent higher risk of ischemic stroke, the kind that occurs when a clot blocks an artery.

Another dietary study in the same issue of the journal found the type of fats consumed by middle-aged men might be more important than overall fat intake in reducing the risk of death from cardiovascular disease.

Heart experts have long recommended polyunsaturated fats and linoleic acids to reduce risk. The study of 1,551 middle-aged men by physicians at the University of Kuopio in Finland found those whose blood levels of those fats were in the upper third were up to three times less likely to die of cardiovascular disease than men with the lowest blood levels. But total fat intake was not associated with the risk of death, the study found.

"Dietary fat quality thus seems more important than fat quantity in the reduction of cardiovascular mortality in middle-aged men," the researchers wrote.

More information

The American Heart Association has more about fish and cardiovascular health.

SOURCES: Dariush Mozaffarian, M.D., instructor, medicine, Channing Laboratory, Harvard School of Public Health, Boston; Jan. 24, 2005, Archives of Internal Medicine

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