Modest effects of dietary supplements during the COVID-19 pandemic: insights from 445 850 users of the COVID-19 Symptom Study app

  1. Panayiotis Louca
  2. Benjamin Murray
  3. Kerstin Klaser
  4. Mark S Graham
  5. Mohsen Mazidi
  6. Emily R Leeming
  7. Ellen Thompson
  8. Ruth Bowyer
  9. David A Drew
  10. Long H Nguyen
  11. Jordi Merino
  12. Maria Gomez
  13. Olatz Mompeo
  14. Ricardo Costeira
  15. Carole H Sudre
  16. Rachel Gibson
  17. Claire J Steves
  18. Jonathan Wolf
  19. Paul W Franks
  20. Sebastien Ourselin
  21. Andrew T Chan
  22. Sarah E Berry
  23. Ana M Valdes
  24. Philip C Calder
  25. Tim D Spector
  26. Cristina Menni

Reviewed by

Read the full article See related articles

Listed in

Log in to save this article

Abstract

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 these observational findings before any therapeutic recommendations can be made.

Article activity feed

  1. Version published to 10.1136/bmjnph-2021-000250
  2. ScreenIT

    SciScore for 10.1101/2020.11.27.20239087: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    Institutional Review Board StatementIRB: Ethics: Ethical approval for use of the app for research purposes in the UK was obtained from King’s College London Ethics Committee (review reference LRS-19/20-18210) and all users provided consent for non-commercial use.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variablenot detected.

    Table 2: Resources

    Software and Algorithms
    SentencesResources
    Statistical analysis was performed using Stata v12 and ExeTera, a Python library developed at KCL to clean and process the raw dataset [20].
    Python
    suggested: (IPython, RRID:SCR_001658)

    Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).

    Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:
    Our study also has a number of limitations. First, we used self-reported data which can introduce information bias, including misclassification, or effect bias exposure if they started taking supplements after developing symptoms. We believe this is possible-although would have reduced any real effect. Second, participants using the app were a self-selected group and may not be fully representative of the general population, and may be affected by collider bias [50]. Third, the SARS-CoV-2 infection diagnosis was mainly based on the RT-PCR test that has less than 100% sensitivity (true positive rate) [51,52]. Fourth, participants might have been taking supplements in addition to the seven we asked them about. Fifth, we do not know the exact intakes of the ingredients within the supplements used by the participants. Finally, this is an observational cross-sectional study captured during a specific timeframe, and our study design does not allow an inference of causality. In conclusion, our data find a correlation between use of multivitamins, omega-3 fatty acids, vitamin D and probiotics and slightly lower risk of SARS-CoV-2 infection in women in the UK, US and SE, but no effect of zinc, vitamin C or garlic. The larger anosmia data confirmed a more modest effect. Given the interest in supplements during the pandemic, large randomised controlled trials of selected supplements testing their protective effects and also possible adverse effects on disease severity are required befor...

    Results from TrialIdentifier: No clinical trial numbers were referenced.

    Results from Barzooka: We did not find any issues relating to the usage of bar graphs.

    Results from JetFighter: We did not find any issues relating to colormaps.

    Results from rtransparent:
    • Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
    • No protocol registration statement was detected.

    About SciScore

    SciScore is an automated tool that is designed to assist expert reviewers by finding and presenting formulaic information scattered throughout a paper in a standard, easy to digest format. SciScore checks for the presence and correctness of RRIDs (research resource identifiers), and for rigor criteria such as sex and investigator blinding. For details on the theoretical underpinning of rigor criteria and the tools shown here, including references cited, please follow this link.

  3. Version published to 10.1101/2020.11.27.20239087v1 on medRxiv