ArticleBMJ nutrition, prevention & health2021
Modest effects of dietary supplements during the COVID-19 pandemic: insights from 445 850 users of the COVID-19 Symptom Study app.
Article in BMJ nutrition, prevention & health, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 75 papers, 4 of them syntheses that pooled it.
What it found
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
75 citing papers in PubMed, 4 syntheses or guidelines pooled it, 141 citations in OpenAlex.
- The effectiveness of interventions to reduce the transmission of acute respiratory infections in care homes: a systematic review.Journal of public health (Oxford, England) · 2024Pooled it
- Probiotics for the prevention and treatment of COVID-19: a rapid systematic review and meta-analysis.Frontiers in nutrition · 2023Pooled it
- The effect of adherence to high-quality dietary pattern on COVID-19 outcomes: A systematic review and meta-analysis.Journal of medical virology · 2023Pooled it
- The effect of polyunsaturated fatty acids on the severity and mortality of COVID patients: A systematic review.Life sciences · 2022Pooled it
- Effect of a test-and-treat approach to vitamin D supplementation on risk of all cause acute respiratory tract infection and covid-19: phase 3 randomised controlled trial (CORONAVIT).BMJ (Clinical research ed.) · 2022Trial
- Prevention of covid-19 and other acute respiratory infections with cod liver oil supplementation, a low dose vitamin D supplement: quadruple blinded, randomised placebo controlled trial.BMJ (Clinical research ed.) · 2022Trial
- Effect of a Nutritional Support System to Increase Survival and Reduce Mortality in Patients with COVID-19 in Stage III and Comorbidities: A Blinded Randomized Controlled Clinical Trial.International journal of environmental research and public health · 2022Trial
- Sustained Shifts in Dietary Supplement Use Years After COVID-19: A Post-Pandemic Evaluation of Behaviors, Perceptions, and Predictors of Change in Jordan.Risk management and healthcare policy · 2026Article
- Multivitamin-mineral supplementation prevents acute upper respiratory tract infections.Asia Pacific journal of clinical nutrition · 2025Article
- Specialized Pro-Resolving Lipid Mediators in Pulmonary Diseases: Molecular and Therapeutic Implications.Molecules (Basel, Switzerland) · 2025Review
- Association of Serum Polyunsaturated Fatty Acids (PUFAs) and Children's Dietary Inflammatory Index (C-DIINutrients · 2024Article
- Article
- Exploring the Dietary Supplement Use During COVID-19: Insights from Community Pharmacists, Pharmacy Staff, Academics, and Industry Experts.Journal of integrative and complementary medicine · 2024Article
- A cross-sectional study exploring general practitioners' views on dietary supplements.BMC primary care · 2024Article
- A post-pandemic trend in the consumption of dietary supplements among residents of Lithuania.Central European journal of public health · 2024Observational
- COVID-19, Nutrients and Lifestyle Eating Behaviors: A Narrative Review.Diseases (Basel, Switzerland) · 2024Review
- Consumption of Dietary Supplements among Working-Age Residents of Lithuania in the Period from 2021 to 2023.Medicina (Kaunas, Lithuania) · 2024Article
- The Association between Lifestyle Factors and COVID-19: Findings from Qatar Biobank.Nutrients · 2024Article
- COVID-19 and Comorbidities: What Has Been Unveiled by Metabolomics?Metabolites · 2024Review
- Clinical Evidence on the Potential Beneficial Effects of Diet and Dietary Supplements against COVID-19 Infection Risk and Symptoms' Severity.Medical sciences (Basel, Switzerland) · 2024Review
15 more citing papers are in PubMed but not listed here.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
26 authors at 7 institutions in 3 countries.
Funding
Abstract
objectivesDietary 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.
designApp-based community survey.
setting445 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 measuresSARS-CoV-2 infection confirmed by viral RNA reverse transcriptase PCR test or serology test before 31 July 2020.
resultsIn 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.
conclusionIn 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.
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