Omega-3 Long-Chain Polyunsaturated Fatty Acids: Are They Beneficial for Physical and Cognitive Functioning in Older Adults?

Background: There is equivocal evidence about beneficial properties of omega-3 long-chain polyunsaturated fatty acids (ω-3 LCPUFA) for older adults. Objective: This study investigated the relationship between circulating ω-3 LCPUFA, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) levels and their corresponding dietary intakes with cognition and physical function in a cohort of community-dwelling older adults at risk of dementia. Methods: A cross-sectional analysis was conducted among 142 community-dwelling older adults (60–85 years) with subjective memory complaints. Erythrocyte fatty acids (ω-3 LCPUFA) and the omega-3 index were measured; dietary DHA and EPA were assessed with a LCPUFA specific questionnaire. Cognition was measured using the Cogstate computerised battery and Trail-making tests. Muscle strength was assessed by grip strength and physical function via the four-square step test, 30-second sit-to-stand, timed up-and-go test, and 4-m walk test. Multiple regression analysis was used to assess the relationship between erythrocyte ω-3 LCPUFA, dietary intake, cognitive and physical function. Results: Higher dietary DHA and EPA were associated with better global cognitive function (DHA: β=0.164, p=0.042; EPA: β=0.188, p=0.020). Higher dietary EPA was associated with better attention/psychomotor composite scores (β=0.196, p=0.024), mobility (four-square step test: β=−0.202, p=0.015) and gait speed (4m walk test: β=−0.200, p=0.017). No associations were found between erythrocyte ω-3 LCPUFA and cognitive or functional performance measures. Conclusions: In community-dwelling older adults with subjective memory complaints, higher dietary ω-3 LCPUFA intake was associated with better cognitive and physical function, supporting the evidence that ω-3 fatty acids play a role in optimising physical and cognitive health during ageing.