Background: Evidence regarding the effects of the omega-3 fatty acids DHA and EPA on cognition is lacking.

Objectives: We investigated whether supplementation with oils rich in EPA or DHA improves cognition.

Methods: Healthy adults (n = 310) completed a 26-wk randomized controlled trial in which they consumed either 900 mg DHA and 270 mg EPA, 360 mg DHA and 900 mg EPA, or 3000 mg/d refined olive oil (placebo). Cognitive performance and memory consolidation were assessed via computerized cognitive test battery.

Results: Both global accuracy and speed improved with EPA-rich oil compared with placebo and DHA-rich oil. Accuracy of memory was improved with EPA compared with DHA.

Conclusions: EPA supplementation improved global cognitive function and was superior to the oil enriched with DHA.