Habitual fish oil use and risk of COVID-19-related outcomes: Evidence from a large scale cohort study and Mendelian randomization analysis

Background & aims: Previous findings for the effects of fish oil on COVID-19-related outcomes remain largely inconclusive and controversy persists. Large population-based studies in real-life settings are required to explore the impact of habitual fish oil use on Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, Coronavirus disease 2019 (COVID-19)-related hospitalization and death. To investigate the associations between habitual fish oil use and SARS-CoV-2infection, COVID-19-related outcome.Methods: Cohort study based on the UK Biobank. 466,572 participants were enrolled. For Mendelian randomization (MR) study, single-nucleotide variants were selected for exposures of fish-oil-derived n-3 PUFAs, including docosapentaenoic acid (DPA).Results: 146,969 (31.5%) participants reported their habitual fish oil use at baseline. Compared with non-fish-oil-users, the hazard ratios for habitual users were 0.97 (95% confidence interval [CI] 0.94 to 0.99) for SARS-CoV-2 infection, 0.92 (95% CI 0.85 to 0.98) for COVID-19-related hospitalization and 0.86 (95% CI 0.75 to 0.98) for COVID-19-related death. MR showed that a higher level of circulating DPA is casually associated with a lower risk of severe COVID-19 (IVW, odds ratio = 0.26, 95% CI 0.08-0.88, P = 0.030).Conclusions: In this large cohort, we found that habitual fish oil use was significantly associated with lower risks of SARS-CoV-2 infection, hospitalization and death from COVID-19. MR analyses further support a possible causal role of DPA, one of the components of fish oil and valid biomarkers of dietary intake, in reducing the risk of severe COVID-19. & COPY; 2023 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

Automated summary

This cohort study based on the UK Biobank found that habitual fish oil use was significantly associated with lower risks of SARS-CoV-2 infection, hospitalization, and death from COVID-19. Mendelian randomization analysis further supported a possible causal role of the DPA component in fish oil in reducing the risk of severe COVID-19.