Effects of n-3 fatty acids on cognitive decline: a randomized, double-blind, placebo-controlled trial in stable myocardial infarction patients

Alzheimers Dement. 2012 Jul;8(4):278-87. doi: 10.1016/j.jalz.2011.06.002. Epub 2011 Oct 2.

Abstract

Background: Epidemiological studies suggest a protective effect of n-3 fatty acids derived from fish (eicosapentaenoic acid [EPA] and docosahexaenoic acid [DHA]) against cognitive decline. For α-linolenic acid (ALA) obtained from vegetable sources, the effect on cognitive decline is unknown. We examined the effect of n-3 fatty acid supplementation on cognitive decline in coronary heart disease patients.

Methods: The analysis included 2911 coronary patients (78% men) aged 60 to 80 years who participated in a double-blind placebo-controlled trial of n-3 fatty acids and cardiovascular diseases (Alpha Omega Trial). By using a 2 × 2 factorial design, patients were randomly assigned to margarines that provided 400 mg/d of EPA-DHA, 2 g/d of ALA, both EPA-DHA and ALA, or placebo for 40 months. Cognitive function was assessed by the Mini-Mental State Examination (MMSE) at baseline and after 40 months. The effect of n-3 fatty acids on change in MMSE score was assessed using analysis of variance. Logistic regression analysis was used to examine the effects on risk of cognitive decline, defined as a decrease of 3 or more points in MMSE score or incidence of dementia.

Results: Patients in the active treatment groups had an additional intake of 384 mg of EPA-DHA, 1.9 g of ALA, or both. The overall MMSE score in this cohort was 28.3 ± 1.6 points, which decreased by 0.67 ± 2.25 points during follow-up. Changes in MMSE score during intervention did not differ significantly between EPA-DHA and placebo (-0.65 vs -0.69 points, P = .44) or between ALA and placebo (-0.60 vs -0.74 points, P = .12). The risk of cognitive decline was 1.03 (95% confidence interval: 0.84-1.26, P = .80) for EPA-DHA (vs placebo) and 0.90 (0.74-1.10, P = .31) for ALA (vs placebo).

Conclusion: This large intervention study showed no effect of dietary doses of n-3 fatty acids on global cognitive decline in coronary heart disease patients.

Trial registration: ClinicalTrials.gov NCT00127452.

Publication types

  • Randomized Controlled Trial
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Cognition Disorders / diet therapy*
  • Cognition Disorders / etiology*
  • Double-Blind Method
  • Fatty Acids, Omega-3 / administration & dosage*
  • Female
  • Humans
  • Logistic Models
  • Longitudinal Studies
  • Male
  • Mental Status Schedule
  • Middle Aged
  • Myocardial Infarction / complications*
  • Neuropsychological Tests
  • Treatment Outcome

Substances

  • Fatty Acids, Omega-3

Associated data

  • ClinicalTrials.gov/NCT00127452