For seniors, eating tuna or fish that’s been broiled or baked appears to lower stroke risk, but frying the catch of the day may increase it, according to new study findings released Monday.

U.S. investigators found that people aged 65 and older who ordered frequent servings of tuna or other types of broiled or baked fish were up to 30 percent less likely than people who ate fish less than once per month to experience a stroke over a 12-year period.

In contrast, people who ate fish sandwiches or fried fish more than once per week had a more than 40 percent higher risk of stroke over the same time period, compared with people who ordered the fare less than once per month, the authors report in the Archives of Internal Medicine.

“Based on the results of these and prior studies, intake of fatty (oily) fish 1 to 2 times per week is likely beneficial for cardiovascular health,” study author Dr. Dariush Mozaffarian told Reuters Health.

Mozaffarian explained that people who ate a lot of tuna and fish that’s been broiled or baked may get more omega-3 fatty acids, which research shows can be good for the blood vessels, blood pressure and inflammation. Improving these factors can decrease stroke risk, noted the researcher, who is based at Brigham and Women’s Hospital and Harvard University in Boston.

In contrast, fish that is fried or put into fish sandwiches is typically white fish, which is low in fish oil and, therefore, low in omega-3 fatty acids, Mozaffarian noted.

“The higher risk of stroke seen with fried fish intake may be due to the fish itself (i.e., from contaminants such as mercury), the method of preparation, or other lifestyle habits associated with fried fish intake,” he said. Further research is needed to identify which explanation is correct, he added.

Previous research looking at fish’s influence on stroke has been inconsistent, Mozaffarian and his team write, and no studies have looked only at the elderly. To investigate further, the researchers followed 4775 people aged 65 and older for 12 years, noting what type of fish they ate and how frequently they ate it, and recording who experienced a stroke.

Eating fish at least 5 times per week did not appear to reduce stroke risk any more than 1 to 4 servings per week, Mozaffarian and his team found.

The researcher noted that tuna, in particular, may be protective of stroke because it is “moderately high” in omega-3 fatty acids. “Other types of oily fish, such as salmon, herring, mackerel, or anchovies, have even higher omega-3 fatty acid content,” Mozaffarian added.

SOURCE: Archives of Internal Medicine, January 24, 2005