The role that marine omega-3 polyunsaturated fatty acids (PUFAs) may play in reducing the risk for developing depression and/or anxiety is unclear. The present study examined the relationships between plasma levels of total omega-3 PUFAs, docosahexaenoic acid (DHA) and the non-DHA omega-3 PUFAs with medical-record documented depression and/or anxiety (both historical and recent, within the last 12 months) in the UK Biobank. The associations of these outcomes with the reported use of fish oil supplements (FOS) were also examined. Data from 258,354 participants who had data on plasma omega-3 PUFA levels and all covariates were used for the biomarker-based analyses, and data from 468,145 people who reported FOS use at baseline were used in the latter analysis. We found that all three omega-3 PUFA metrics were inversely associated with a history of both depression and anxiety. Specifically, risk for the former outcome was between 15% and 33% lower in Q5 vs Q1, and for the latter outcome, between 19% to 22% lower comparing Q5 with Q1. Risk for recent depression was 29% and 32% lower (Q5 vs Q1) for total omega-3 PUFAs and for non-DHA, respectively. FOS use was associated with a 9-10% lower risk for a history of depression and anxiety, respectively, and a 20% lower risk for recent anxiety. In conclusion, we found evidence that higher levels of omega-3 PUFAs may play a protective role in depression and anxiety.

WSH holds an interest in OmegaQuant Analytics, a laboratory that offers blood fatty acid testing for consumers, clinicians and researchers. PPD, RWG and SHM are employees of Pharmavite, LLC. NLT and JP have nothing to declare.

This study was supported in part by a grant from Pharmavite, LLC

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Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

UK Biobank

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I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

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All data produced in the present study are available upon reasonable request to the authors but the requester must also obtain permission from the UKBB for the use of these data.