Omega-3 and polyunsaturated fat for prevention of depression and anxiety symptoms: a systematic review and meta-analysis of randomised trials

Deane, Katherine H. O., Jimoh, Oluseyi F., Biswas, Priti, O'Brien, Alex, Hanson, Sarah, Abdelhamid, Asmaa S., Fox, Chris and Hooper, Lee (2021) Omega-3 and polyunsaturated fat for prevention of depression and anxiety symptoms: a systematic review and meta-analysis of randomised trials. The British Journal of Psychiatry, 218 (3). pp. 135-142. ISSN 0007-1250

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Abstract

Background There is strong public belief that polyunsaturated fats protect against and ameliorate depression and anxiety. Aims To assess effects of increasing omega-3, omega-6 or total polyunsaturated fat on prevention and treatment of depression and anxiety symptoms. Method We searched widely (Central, Medline and EMBASE to April 2017, trial registers to September 2016, ongoing trials updated to August 2019), including trials of adults with or without depression or anxiety, randomised to increased omega-3, omega-6 or total polyunsaturated fat for ≥24 weeks, excluding multifactorial interventions. Inclusion, data extraction and risk of bias were assessed independently in duplicate, and authors contacted for further data. We used random-effects meta-analysis, sensitivity analyses, subgrouping and Grading of Recommendations, Assessment, Development and Evaluations (GRADE) assessment. Results We included 31 trials assessing effects of long-chain omega-3 (n = 41 470), one of alpha-linolenic acid (n = 4837), one of total polyunsaturated fat (n = 4997) and none of omega-6. Meta-analysis suggested that increasing long-chain omega-3 probably has little or no effect on risk of depression symptoms (risk ratio 1.01, 95% CI 0.92-1.10, I2 = 0%, median dose 0.95 g/d, duration 12 months) or anxiety symptoms (standardised mean difference 0.15, 95% CI 0.05-0.26, I2 = 0%, median dose 1.1 g/d, duration 6 months; both moderate-quality evidence). Evidence of effects on depression severity and remission in existing depression were unclear (very-low-quality evidence). Results did not differ by risk of bias, omega-3 dose, duration or nutrients replaced. Increasing alpha-linolenic acid by 2 g/d may increase risk of depression symptoms very slightly over 40 months (number needed to harm, 1000). Conclusions Long-chain omega-3 supplementation probably has little or no effect in preventing depression or anxiety symptoms. Declaration of interest L.H. and A.A. were funded to attend the World Health Organization Nutrition Guidance Expert Advisory Group (NUGAG) Subgroup on Diet and Health meetings and present review results. The authors report no other conflicts of interest.

Item Type: Article
Uncontrolled Keywords: fatty acids omega-3,anxiety,depression,fatty acids omega-6,meta-analysis,psychiatry and mental health ,/dk/atira/pure/subjectarea/asjc/2700/2738
Faculty \ School: Faculty of Medicine and Health Sciences > School of Health Sciences
Faculty of Medicine and Health Sciences > Norwich Medical School
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Depositing User: LivePure Connector
Date Deposited: 26 Sep 2019 09:30
Last Modified: 13 May 2021 14:03
URI: https://ueaeprints.uea.ac.uk/id/eprint/72390
DOI: 10.1192/bjp.2019.234

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