In the first study, researchers from Harvard investigated how fried and non-fried fish affect incidence of ischemic stroke in 4,775 elderly subjects. They found tuna or other broiled or baked fish is associated with decreased risk of ischemic stroke, while fried fish or fish sandwiches were linked to higher stroke risk.
Non-fried fish contribute healthy Omega-3 fatty acids DHA and EPA to the diet. Fried fish contribute an abundance of Omega-6 linolenic acid (LA) which offset the beneficial effects of the Omega-3's.
In the other study, researchers from Finland investigated the association of dietary linoleic acid (LA) and total polyunsaturated fats (PUFAs) intake with cardiovascular and overall mortality in a population cohort of 1,551 middle-aged men. During the 15-year follow-up, 78 men died of cardiovascular disease (CVD), while 225 died of other causes. Total fat was not related to CVD death, while men with the highest levels of LA had a lower mortality rate than men with the lowest LA intakes. Serum, and to a lesser extent, dietary LA and PUFA levels were also inversely related to overall mortality. Researchers noted dietary fat quality seems more important than fat quantity in the reduction of CVD mortality in men.
Background Associations between fish consumption and stroke risk have been inconsistent, possibly because of the differences in types of fish meals consumed. Additionally, such relationships have not been specifically evaluated in the elderly, in whom disease burden may be high and diet less influential.
Methods Among 4775 adults 65 years or older (range, 65-98 years) and free of known cerebrovascular disease at baseline in 1989-1990, usual dietary intake was assessed using a food frequency questionnaire. In a subset, consumption of tuna or other broiled or baked fish, but not fried fish or fish sandwiches (fish burgers), correlated with plasma phospholipid long-chain n-3 fatty acid levels. Incident strokes were prospectively ascertained.
Results During 12 years of follow-up, participants experienced 626 incident strokes, including 529 ischemic strokes. In multivariate analyses, tuna/other fish consumption was inversely associated with total stroke (P = .04) and ischemic stroke (P = .02), with 27% lower risk of ischemic stroke with an intake of 1 to 4 times per week (hazard ratio [HR], 0.73; 95% confidence interval [CI], 0.55-0.98) and 30% lower risk with intake of 5 or more times per week (HR, 0.70; 95% CI, 0.50-0.99) compared with an intake of less than once per month. In contrast, fried fish/fish sandwich consumption was positively associated with total stroke (P = .006) and ischemic stroke (P = .003), with a 44% higher risk of ischemic stroke with consumption of more than once per week (HR, 1.44; 95% CI, 1.12-1.85) compared with consumption of less than once per month. Fish consumption was not associated with hemorrhagic stroke.
Conclusions Among elderly individuals, consumption of tuna or other broiled or baked fish is associated with lower risk of ischemic stroke, while intake of fried fish or fish sandwiches is associated with higher risk. These results suggest that fish consumption may influence stroke risk late in life; potential mechanisms and alternate explanations warrant further study.
Dariush Mozaffarian, MD, MPH; W. T. Longstreth, Jr, MD; Rozenn N. Lemaitre, PhD, MPH; Teri A. Manolio, MD, PhD; Lewis H. Kuller, MD, DrPH; Gregory L. Burke, MD, MS; David S. Siscovick, MD, MPH; Fish Consumption and Stroke Risk in Elderly Individuals; Archives of Internal Medicine; Jan. 24, 2005; 165, 2:200-206, 2005 (http://archinte.ama-assn.org).
Archives of Internal Medicine; Jan. 24, 2005; 165, 2:193-199, 2005.