No effect of n-3 long-chain polyunsaturated fatty acid (EPA and DHA) supplementation on depressed mood and cognitive function: a randomised controlled trial

British Journal of Nutrition
Q1
Feb 2008
Citations:275
Influential Citations:21
Interventional (Human) Studies
95
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Enhanced Details

Methods
Design: single-centre, double-blind randomized controlled trial. Participants: adults aged 18-70 with mild-to-moderate depressed mood (DASS depression score 10-24), not pregnant or breastfeeding, not severely ill, not taking antidepressants. 218 randomized; 190 completed 12 weeks; recruitment largely via general practice in Bristol; groups roughly 109 per arm; baseline characteristics similar (mean age ~38 years; ~76-78% female).
Intervention
Three capsules daily for 12 weeks; active treatment delivered a daily total of 630 mg EPA, 850 mg DHA, 870 mg olive oil, 7.5 mg mixed tocopherols and 12 mg orange oil.
Results
EPA+DHA supplementation for 12 weeks did not improve depressed mood or cognitive function compared with placebo. Primary outcome (DASS depression) adjusted mean difference −1.0 points (95% CI −2.8, 0.8; P = 0.27); mean DASS depression at 12 weeks 8.4 (EPA+DHA) vs 9.6 (placebo). Other mood measures (BDI, DASS anxiety/stress, GHQ) and cognitive tasks showed no meaningful effects. Plasma EPA+DHA increased twofold in the active group; compliance was high; the supplement was well tolerated. Authors concluded no beneficial or harmful mood effects from increasing EPA+DHA intake for 12 weeks; adding this trial to meta-analyses yields an overall negligible benefit of n-3 LCPUFA supplementation for depressed mood.
Limitations
Single-centre trial; participants had mild-to-moderate depressive symptoms (not major depression), limiting generalizability to clinical depression; 12-week duration; mood diaries and some cognitive measures had incomplete data; multiple secondary outcomes raise risk of Type I error.

Abstract

Low dietary intakes of the n-3 long-chain PUFA (LCPUFA) EPA and DHA are thought to be associated with increased risk for a variety of adverse outcomes, including some psychiatric disorders. Evidence from observational and intervention studies for a r...