Supplementation With Oil Rich In Eicosapentaenoic Acid, But Not In Docosahexaenoic Acid, Improves Global Cognitive Function In Healthy, Young Adults: Results From Randomized Controlled Trials

Background: Evidence regarding the effects of the omega-3 (omega-3) PUFAs (n-3 PUFAs) DHA and EPA on cognition is lacking.Objectives: We investigated whether supplementation with oils rich in EPA or DHA improves cognition, prefrontal cortex (PFC) hemoglobin (Hb) oxygenation, and memory consolidation.Methods: Healthy adults (n = 310; age range: 25-49 y) completed a 26-wk randomized controlled trial in which they consumed either 900 mg DHA/d and 270 mg EPA/d (DHA-rich oil), 360 mg DHA/d and 900 mg EPA/d (EPA-rich oil), or 3000 mg/d refined olive oil (placebo). Cognitive performance and memory consolidation were assessed via computerized cognitive test battery. PFC Hb oxygenation was measured using near infrared spectroscopy (NIRS).Results: Both global accuracy and speed improved with EPA-rich oil compared with placebo and DHA-rich oil [EPA vs. placebo accuracy: estimated marginal mean (EMM) = 0.17 (95% CI: 0.09, 0.24) vs. EMM = 0.03 (95% CI = -0.04. 0.11); P = 0.044; EPA vs. placebo speed: EMM = -0.15 (95% CI: -0.22, -0.07) vs. EMM = 0.03 (95% CI: -0.05, 0.10); P = 0.003]. Accuracy of memory was improved with EPA compared with DHA [EMM = 0.66 (95% CI: 0.26, 1.06) vs. EMM = -0.08 (95% CI: -0.49, 0.33); P = 0.034]. Both EPA- and DHA -rich oils showed trends towards reduced PFC oxygenated Hb (oxy-Hb) compared with placebo [placebo: EMM = 27.36 mu M (95% CI: 25.73, 28.98); DHA: EMM = 24.62 mu M (95% CI: 22.75, 26.48); P = 0.060; EPA: EMM = 24.97 mu M (95% CI: 23.35, 26.59): P = 0.082].Conclusions: EPA supplementation improved global cognitive function and was superior to the oil enriched with DHA. Interpreted within a neural efficiency framework, reduced PFC oxygenated Hb suggests that n-3 PUFAs may be associated with increased efficiency.