Consumption of seafood was associated with slower decline in semantic memory (β = 0.024; p = 0.03) and perceptual speed (β = 0.020; p = 0.05) in separate models adjusted for age, sex, education, participation in cognitive activities, physical activity, alcohol consumption, smoking, and total energy intake. In secondary analyses, APOE ε4 carriers demonstrated slower rates of decline in global cognition and in multiple cognitive domains with weekly seafood consumption and with moderate to high long-chain n-3 fatty acid intake from food. These associations were not present in APOE ε4 noncarriers. Higher intake levels of α-linolenic acid were associated with slower global cognitive decline, but also only in APOE ε4 carriers.
These results suggest protective relations of one meal per week of seafood and long-chain n-3 fatty acids against decline in multiple cognitive domains. The role of APOE ε4 in this association needs further study.