Panayiotis Louca , Benjamin Murray , Kerstin Klaser , Mark S Graham , Mohsen Mazidi , Emily R Leeming , Ellen Thompson , Ruth Bowyer , David A Drew ,3Long H Nguyen , Jordi Merino , Maria Gomez , Olatz Mompeo , Ricardo Costeira , Carole H Sudre , Rachel Gibson , Claire J Steves , Jonathan Wolf , Paul W Franks , Sebastien Ourselin , Andrew T Chan , Sarah E Berry , Ana M Valdes , Philip C Calder , Tim D Spector , Cristina Menni
bmjnph 2021;0. doi:10.1136/bmjnph-2021-000250
Objectives Dietary supplements may ameliorate SARS-CoV-2 infection, although scientific evidence to support such a role is lacking. We investigated whether users of
the COVID-19 Symptom Study app who regularly took dietary supplements were less likely to test positive for SARS-CoV-2 infection.
Design App-based community survey.
Setting 445 850 subscribers of an app that was launched to enable self-reported
information related to SARS-CoV- 2 infection for use in the general population in the UK (n=372 720), the USA (n=45 757) and Sweden (n=27 373).
Main exposure Self-reported regular dietary supplement usage (constant use during previous 3 months) in the first waves of the pandemic up to 31 July 2020.
Main outcome measures SARS-CoV- 2 infection confirmed by viral RNA reverse transcriptase PCR test or serology test before 31 July 2020.
Results In 372 720 UK participants (175 652 supplement users and 197 068 non-users),
those taking probiotics, omega-3 fatty acids, multivitamins or vitamin D had a lower risk of SARS-CoV-2 infection by 14% (95% CI (8% to 19%)), 12% (95% CI (8% to 16%)), 13% (95% CI (10% to 16%)) and 9% (95% CI (6% to 12%)), respectively, after adjusting for potential confounders. No effect was observed for those taking vitamin C, zinc or garlic supplements. On stratification by sex, age and body mass index (BMI), the protective associations in individuals taking probiotics, omega-3 fatty acids, multivitamins and vitamin D were observed in females across all ages and BMI groups, but were not seen in men. The same overall pattern of association was observed in both the US and Swedish cohorts.
Conclusion In women, we observed a modest but significant association between use of probiotics, omega-3 fatty acid, multivitamin or vitamin D supplements and lower risk of testing positive for SARS-CoV- 2. We found no clear benefits for men nor any effect of vitamin C, garlic or zinc. Randomised controlled trials are required to confirm