SynthesisBMJ global health2021
Effect of micronutrient supplements on influenza and other respiratory tract infections among adults: a systematic review and meta-analysis.
Synthesis in BMJ global health, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 53 papers, 9 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
53 citing papers in PubMed, 9 syntheses or guidelines pooled it, 92 citations in OpenAlex.
- Effect of vitamin D status and vitamin D supplementation on immune function and prevention of acute respiratory tract infections in dark-skinned individuals: a systematic review and meta-analysis.Public health nutrition · 2024Pooled it
- Optimal methods of vitamin D supplementation to prevent acute respiratory infections: a systematic review, dose-response and pairwise meta-analysis of randomized controlled trials.Nutrition journal · 2024Pooled it
- Vitamin D supplementation for prevention of acute respiratory infections in older adults: A systematic review and meta-analysis.PloS one · 2024Pooled it
- Impact of intravenous vitamin C as a monotherapy on mortality risk in critically ill patients: A meta-analysis of randomized controlled trials with trial sequential analysis.Frontiers in nutrition · 2023Pooled it
- Select Dietary Supplement Ingredients for Preserving and Protecting the Immune System in Healthy Individuals: A Systematic Review.Nutrients · 2022Pooled it
- Efficacy of Vitamin D Supplements in Prevention of Acute Respiratory Infection: A Meta-Analysis for Randomized Controlled Trials.Nutrients · 2022Pooled it
- Vitamin D supplementation for the treatment of COVID-19: A systematic review and meta-analysis of randomized controlled trials.Frontiers in immunology · 2022Pooled it
- Pooled it
- Micronutrients Deficiency, Supplementation and Novel Coronavirus Infections-A Systematic Review and Meta-Analysis.Nutrients · 2021Pooled it
- The effect of standard-dose wintertime vitamin D supplementation on influenza infection in immunized nursing home elderly residents.Croatian medical journal · 2021Trial
- Micronutrients and omega-3 PUFAs to promote healthy ageing: informing a physiology-based complementation strategy.GeroScience · 2026Review
- Serum Vitamin D Levels, Systemic Inflammation, and Exacerbation Among Patients with COPD GOLD Group E.Biomedicines · 2026Article
- Article
- Vitamin D in Infectious Diseases: A Narrative Review Focusing on COVID-19, Long COVID, and Influenza.Nutrients · 2026Review
- The immune system as a guardian of health: micronutrient support and lifelong protection.Frontiers in nutrition · 2026Review
- A nutritionally balanced menu for emergencies: beyond the COVID-19 pandemic.Frontiers in nutrition · 2026Article
- Bronchiolitis and recurrent respiratory infections: The role of oxidative stress from early life inflammation to long-term outcomes - A narrative review.The World Allergy Organization journal · 2026Review
- Comparative effectiveness of oral nutritional supplements in preventing respiratory tract infections among adults: a systematic review and network meta-analysis.EClinicalMedicine · 2025Article
- Risk and resilience factors associated with the progression of influenza to severe disease outcomes: umbrella review protocol.BMJ open · 2025Article
- Multivitamin-mineral supplementation prevents acute upper respiratory tract infections.Asia Pacific journal of clinical nutrition · 2025Article
Corrections and comments
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Authors and funding
3 authors at 2 institutions in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Acute respiratory tract infections (ARIs) are a leading cause of ill-health and death globally. Individual or multiple micronutrients have been shown to modulate immune function and affect the risk and severity of a number of infectious diseases. We systematically reviewed the evidence on the impact of micronutrient supplements to reduce the occurrence of ARIs and shorten the duration of ARI symptoms among adults. Random effects meta-analyses were conducted to estimate the pooled effects of vitamin D, vitamin C, zinc and multiple micronutrient supplementation (MMS) on the occurrence of ARIs and the duration of ARI symptoms. Vitamin D supplementation reduced the risk of ARI (risk ratio (RR)=0.97; 95% CI 0.94 to 1.00; p=0.028) and shortened the duration of symptoms (per cent difference: -6% (95% CI -9% to -2%; p=0.003)). The RR of vitamin D to prevent ARI was farther from the null when diagnosis was based on clinical diagnosis or laboratory testing, compared with self-report and when the loading dose was <60 000 IU. Vitamin C supplementation reduced the risk of ARIs (RR=0.96; 95% CI 0.93 to 0.99; p=0.01) and shortened the duration of symptoms (per cent difference: -9% (95% CI -16% to -2%; p=0.014)). The effect of vitamin C on preventing ARI was stronger among men and in middle-income countries, compared with women and high-income countries, respectively. Zinc supplementation did not reduce the risk of ARIs but shortened the duration of symptoms substantially (per cent difference: -47% (95% CI -73% to -21%;
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.