Fish Consumption May Slow Cognitive Decline

Morris MC, Evans DA, Tangney CC, et al. Fish consumption and cognitive decline with age in a large community study. Arch Neurol. 2005; E-pub ahead of print.

Eating one or more fish meals per week may protect against cognitive decline in the elderly, according to Morris and colleagues. Their study was published in the online edition of Archives of Neurology and is scheduled to appear in the December print edition.

The investigators examined data from the ongoing Chicago Health and Aging Project. A total of 3,718 people 65 or older were included in the analysis. Diet was assessed using a modified Harvard Food Frequency Questionnaire, which asked about usual intake of 139 different foods in the past year and included four seafood categories--tuna fish sandwich, fish sticks/fish cakes/fish sandwich, fresh fish as a main dish, and shrimp/lobster/crab. Cognition was measured using the East Boston Tests of Immediate and Delayed Recall, the Mini-Mental State Examination, and the Symbol Digit Modalities Test.

Results indicated that 21.0% of participants ate two or more fish meals per week, 36.3% ate one fish meal per week, and 42.6% ate less than one fish meal per week. Those who consumed fish were more likely to be African-American, to have a cardiovascular-related health condition, and to drink less alcohol.

According to the investigators, the mean cognitive score at baseline was 0.18 standardized units (SU), which declined by 0.04 SU per year. They reported that cognitive decline was slower among people who consumed fish at least once a week. Participants who consumed one fish meal per week and those who consumed two or more fish meals per week experienced annual rates of cognitive decline that were 10% and 13% slower, respectively, than those of participants who did not consume fish, the researchers say.

The association between fish consumption and cognitive decline "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," said the researchers. They added that "there was little evidence that the omega-3 polyunsaturated fatty acids were associated with cognitive change."