Effect of fish-oil supplementation on mental well-being in older subjects: a randomized, double-blind, placebo-controlled trial

Abstract

BackgroundIt is suggested that a low intake of fish and/or n−3 PUFA is associated with depressed mood. However, results from epidemiologic studies are mixed, and randomized trials have mainly been performed in depressed patients, yielding conflicting results. ObjectiveWe investigated the effect of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on mental well-being in a double-blind, placebo-controlled trial. DesignIndependently living individuals (n = 302) aged ≥65 y were randomly assigned to consume 1800 mg/d EPA+DHA, 400 mg/d EPA+DHA, or placebo capsules for 26 wk. Changes in mental well-being were assessed as the primary outcome with the Center for Epidemiologic Studies Depression Scale (CES-D), Montgomery-Åsberg Rating Scale (MADRS), Geriatric Depression Scale (GDS-15), and Hospital Anxiety and Depression Scale (HADS-A). ResultsPlasma concentrations of EPA+DHA increased by 238% in the high-dose and 51% in the low-dose fish-oil group compared with the placebo group, reflecting excellent compliance. Baseline CES-D scores ranged from 5.9 to 6.8 in the 3 groups and were not significantly different between groups. Mean changes in CES-D scores after 26 wk were −0.2, 0.2, and −0.4 (P = 0.87) in the high-dose fish oil, low-dose fish oil, and placebo groups, respectively. Treatment with neither 1800 mg nor 400 mg EPA+DHA differentially affected any of the measures of mental well-being after 13 or 26 wk of intervention compared with placebo. ConclusionsIn this randomized, double-blind, placebo-controlled trial we observed no effect of EPA+DHA supplementation for 26 wk on mental well-being in the general older population studied. This trial was registered at clinicaltrials.gov as NCT00124852.