Cross-sectional association of seafood consumption, polyunsaturated fatty acids and depressive symptoms in two Torres Strait communities

Abstract

Background Dietary intake of long-chain omega 3 (n-3) polyunsaturated fatty acids (LCPUFA) represents a putative modifiable risk factor for depression, and a high ratio of omega 6 (n-6) to n-3 LCPUFA is frequently observed in patients with major depressive disorder. Recent reports suggest that the availability of fish and seafood may be associated with lower depression rates. The aim of this study was to investigate associations of fish consumption and LCPUFA levels with depressive symptoms.

Methods Participants for this cross-sectional study (n=206) were recruited at a community screening programme in two Torres Strait Islander communities (Mer and Waiben). Depressive symptoms were assessed with the adapted Patient Health Questionnaire-9 (aPHQ-9) and diet with a structured questionnaire. LCPUFA concentrations were measured with a capillary dried blood spot system (PUFAcoat). Logistic and quantile regression modelling was used to test the relationship between seafood consumption, membrane LCPUFAs and depression scores.

Results A higher blood n-6/3 LCPUFA ratio was associated with moderate/severe depression scores across both study sites (OR=1.59 (95%CI 1.09–2.34), P = .017). Seafood consumption was higher and the proportion of participants with aPHQ-9 scores above the cut-off for depression was lower on Mer (n = 100) compared with Waiben (n = 106). Higher seafood consumption was associated with lower depression scores on Waiben (B = −0.57 (95%CI −0.98 – −0.16), P = .006) but not on Mer.

Conclusions Our findings support an association of n-3 LCPUFA from natural sources with depressive symptoms. The availability of fresh seafood in the local diet may represent a protective factor for depression in this setting.

Keywords:

• Aboriginal and Torres Strait Islander
• Depression
• Omega-3 fatty acids
• EPA
• DHA
• Screening
• PHQ-9

Acknowledgements

We would like to thank the study participants and their families. This work was funded by NHMRC Grant GNT0631947 and by the Centre for Chronic Disease Prevention. This study was made possible by the contribution of many people, including the Torres and Cape Hospital and Health Service Primary Health Care Team (north), the Torres and Cape Hospital and Health Service Mental Health Team (north), Mer Island Primary Health Care Centre Team, JCU medical and dental students, the Waiben and Mer communities and the many people that gave their time to participate in the health check.

Disclaimer statements

Contributors None.

Funding This work was supported by the National Health and Medical Research Council [grant number GNT0631947].

Conflicts of interest The authors declare no medical or financial conflict of interest. The funding bodies had no role in the design of the study or analysis of the data.

Ethics approval None.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Linton Harriss http://orcid.org/0000-0002-0996-8128

Maria Makrides http://orcid.org/0000-0003-3832-541X

Robert Gibson http://orcid.org/0000-0002-8750-525X