An 18-mo randomized, double-blind, placebo-controlled trial of DHA-rich fish oil to prevent age-related cognitive decline in cognitively normal older adults.

Study answer

What this study found

DHA-rich fish oil did not slow or improve cognitive performance over 18 months. The main cognitive findings were small negative effects on psychomotor speed (treatment = -0.02; 95% CI: -0.04 to 0.00; P = 0.03; d = 0.24) and on simple and choice reaction time (treatment = -0.02; 95% CI: -0.03 to 0.01; P = 0.05; d = 0.20). Sex and APOE-ε4 carrier status moderated some outcomes, including greater decline in retrieval fluency in women and improvement in reasoning among APOE-ε4 carriers. Secondary findings included worse perceived cognitive mistakes (Cognitive Failures Questionnaire, d = 0.24; P…

Study & population

Randomized, double-blind, placebo-controlled trial in cognitively healthy, community-dwelling older adults in Adelaide, South Australia.

Intervention

Participants received oral DHA-rich fish oil capsules for 18 months, 4 capsules per day.

Key limitation

The trial was modest in size for subgroup analyses, and the sex and APOE-ε4 interactions should be considered exploratory.

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Original abstract