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

Am J Clin Nutr. 2021 Sep 1;114(3):914-924. doi: 10.1093/ajcn/nqab174.

Abstract

Background: Evidence regarding the effects of the omega-3 (ɷ-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 µM (95% CI: 25.73, 28.98); DHA: EMM = 24.62 µM (95% CI: 22.75, 26.48); P = 0.060; EPA: EMM = 24.97 µM (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.These trials were registered in the clinical trials registry (https://clinicaltrials.gov/) as NCT03158545, NCT03592251, NCT02763514.

Keywords: cognition; docosahexaenoic acid; eicosapentaenoic acid; memory; n-3 polyunsaturated fatty acids; self-micro-emulsifying.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Cognition / drug effects*
  • Dietary Fats, Unsaturated / analysis*
  • Dietary Supplements*
  • Docosahexaenoic Acids / administration & dosage*
  • Docosahexaenoic Acids / chemistry
  • Docosahexaenoic Acids / pharmacology*
  • Double-Blind Method
  • Eicosapentaenoic Acid / administration & dosage*
  • Eicosapentaenoic Acid / chemistry
  • Eicosapentaenoic Acid / pharmacology*
  • Female
  • Humans
  • Male
  • Middle Aged

Substances

  • Dietary Fats, Unsaturated
  • Docosahexaenoic Acids
  • Eicosapentaenoic Acid

Associated data

  • ClinicalTrials.gov/NCT03158545
  • ClinicalTrials.gov/NCT03592251
  • ClinicalTrials.gov/NCT02763514