Data from 915 older adults (mean age 81.4) participating in the very long-running Rush Memory and Aging Project, has found that those who reported eating seafood less than once a week showed greater cognitive decline compared to those who ate at least one seafood meal per week.

The food questionnaires included four types of seafood: tuna sandwiches; fish sticks, fish cakes and fish sandwiches; fresh fish as a main dish; and shrimp, lobster and crab. Those who ate at least one of those seafood meals per week ate an average of two seafood meals per week. Those and those who ate less than one of those seafood meals per week ate an average of 0.5 meals per week.

People who ate more seafood had better semantic memory and better perceptual speed (the ability to quickly compare letters, objects and patterns), but there wasn’t a significant difference in the rate of decline in episodic memory, working memory or visuospatial ability.

Factors such as education, physical activity, smoking and participating in mentally stimulating activities were taken into account in the analysis.

Interestingly, the protective association of seafood was stronger among those with the “Alzheimer’s gene” (APOE-ε4).