Background: Dietary intake of fish and the omega-3 fatty acids have been associated with lower risk of Alzheimer disease and stroke.
Objective: To examine whether intakes of fish and the omega-3 fatty acids protect against age-related cognitive decline.
Design: Prospective cohort study.
Setting: Geographically defined Chicago, Ill, community.
Participants: Residents, 65 years and older, who participated in the Chicago Health and Aging Project.
Main outcome measure: Change in a global cognitive score estimated from mixed models. The global score was computed by summing scores of 4 standardized tests. In-home cognitive assessments were performed 3 times over 6 years of follow-up.
Results: Cognitive scores declined on average at a rate of 0.04 standardized units per year (SU/y). Fish intake was associated with a slower rate of cognitive decline in mixed models adjusted for age, sex, race, education, cognitive activity, physical activity, alcohol consumption, and total energy intake. Compared with a decline rate in score of -0.100 SU/y among persons who consumed fish less than weekly, the rate was 10% slower (-0.090 SU/y) among persons who consumed 1 fish meal per week and 13% slower (-0.088 SU/y) among persons who consumed 2 or more fish meals per week. The fish association was not accounted for by cardiovascular-related conditions or fruit and vegetable consumption but was modified after adjustment for intakes of saturated, polyunsaturated, and trans fats. There was little evidence that the omega-3 polyunsaturated fatty acids were associated with cognitive change.
Conclusions: Fish consumption may be associated with slower cognitive decline with age. Further study is needed to determine whether fat composition is the relevant dietary constituent.