The omega-3 fatty acids in fish, especially fatty fish, have been associated with a reduction in the risk of stroke, studies have shown. However, research indicates that the process of frying fish causes a loss of these beneficial fatty acids.
The stroke belt states include North Carolina, South Carolina, Georgia, Alabama, Mississippi, Tennessee, Arkansas, and Louisiana. People living in the stroke belt states are more like to have a stroke and to die from stroke than people living in other states, the researchers say.
The scientists also identified a region they called the "stroke buckle," which includes the coastal plain region of North Carolina, South Carolina, and Georgia. People in the stroke buckle are even more likely than those in the stroke belt to have fatal strokes, the researchers say.
The study, published in Neurology, shows that along with a higher consumption of fried fish, people living in the stroke belt are less likely to have an adequate intake of non-fried fish, defined in the study as two or more servings of non-fried fish per week based on guidelines from the American Heart Association.
It also found that African-Americans are more likely to eat two or more servings of fried fish per week than whites. A serving is considered 3 ounces of fish.
"These differences in fish consumption may be one of the potential reasons for the racial and geographic differences in stroke incidence and mortality," says Fadi Nahab, MD, of Emory University in Atlanta and lead author of the study.
Researchers examined data on 21,675 people participating in a study program called REGARDS, for Reasons for Geographic and Racial Differences in Stroke.
Of all the people whose records were examined, 21 percent were from the stroke buckle, 34 percent from the rest of the states in the stroke belt, and 44 percent were from other states.
Study participants were interviewed by telephone and then given an in-home physical examination. They also filled out a questionnaire asking how often they ate oysters, shellfish, tuna, fried fish, and non-fried fish.
Among the key findings:
Fewer than one in four of the people (23 percent) ate two or more servings of non-fried fish per week.
People living in the stroke buckle were 11 percent less likely to eat two or more servings of non-fried fish than participants in the rest of the country.
People in the rest of the stroke belt were 17 percent less likely to eat recommended servings of non-fried fish on a weekly basis.
African-Americans were more than 3.5 times more likely to eat two or more servings of fried fish weekly than whites. African-Americans ate an average of 0.96 servings weekly of fried fish, compared to 0.47 servings for whites.
People in the stroke belt were 30 percent more likely to eat two or more servings of fried fish than people in the rest of the country.
The researchers conclude that racial and geographic differences in fish consumption may be one of the reasons for differences in stroke incidence and death in various areas around the country.
By Bill Hendrick
Laura J. Martin, MD