Association of gut microbiota and dietary component intake with COVID-19: A mendelian randomization study

Background: Growing evidence has indicated that alterations in the gut microbiota and nutritional quality of dietary intake were associated with COVID-19. Whether these associations reflect causality is still unknown. Methods: We performed a two-sample Mendelian randomization analysis using genetic variants as instrumental variables for gut microbiota, dietary component intake, and COVID-19. Findings: We found that the Ruminococcustorques group genus was significantly associated with COVID19. The Ruminococcaceae UCG013 genus and Ruminococcus1 genus were suggestively associated with COVID-19. The Actinobacteria class, Bifidobacteriales order, Bifidobacteriaceae genus, R. group, and Tyzzerella3 genus were potentially associated with severe COVID-19. COVID-19 was significantly associated with the Lachnospira genus, Oscillospira, and RuminococcaceaeUCG009 genus and potentially associated with the Victivallis genus. Severe COVID-19 was significantly associated with the Turicibacter and Olsenella genus and potentially associated with Ruminococcus1, CandidatusSoleaferrea, and Parasutterella genus. Moreover, processed meat intake was significantly associated with COVID-19. Beef intake was suggestively associated with COVID-19. Salt added to food intake, and fresh fruit intake was suggestively associated with severe COVID-19. Conclusions: Our findings provide evidence supporting a causal effect of gut microbiota and dietary intake on COVID-19. We also found the causal effect of COVID-19 on the alteration of gut microbiota. & COPY; 2023 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).