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 (omega-3 LCPUFA) for older adults. Objective This study investigated the relationship between circulating omega-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 (omega-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 omega-3 LCPUFA, dietary intake, cognitive and physical function. Results Higher dietary DHA and EPA were associated with better global cognitive function (DHA: beta=0.164, p=0.042; EPA: beta=0.188, p=0.020). Higher dietary EPA was associated with better attention/psychomotor composite scores (beta=0.196, p=0.024), mobility (four-square step test: beta=-0.202, p=0.015) and gait speed (4m walk test: beta=-0.200, p=0.017). No associations were found between erythrocyte omega-3 LCPUFA and cognitive or functional performance measures. Conclusions In community-dwelling older adults with subjective memory complaints, higher dietary omega-3 LCPUFA intake was associated with better cognitive and physical function, supporting the evidence that omega-3 fatty acids play a role in optimising physical and cognitive health during ageing.

Automated summary

This study examined the relationship between circulating omega-3 LCPUFA levels and dietary intake of DHA and EPA with cognition and physical function in community-dwelling older adults at risk of dementia. Results showed that higher dietary intake of DHA and EPA were associated with better cognitive function, while higher dietary EPA intake was linked to better attention and mobility. No associations were found between erythrocyte omega-3 LCPUFA levels and cognitive or functional performance measures in this cohort.