Trial reportNutrients2014
Vitamin C supplementation slightly improves physical activity levels and reduces cold incidence in men with marginal vitamin C status: a randomized controlled trial.
Trial report in Nutrients, 2014. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 34 papers, 3 of them syntheses that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
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
34 citing papers in PubMed, 3 syntheses or guidelines pooled it, 76 citations in OpenAlex.
- Vitamin C reduces the severity of common colds: a meta-analysis.BMC public health · 2023Pooled it
- Select Dietary Supplement Ingredients for Preserving and Protecting the Immune System in Healthy Individuals: A Systematic Review.Nutrients · 2022Pooled it
- Effect of micronutrient supplements on influenza and other respiratory tract infections among adults: a systematic review and meta-analysis.BMJ global health · 2021Pooled it
- Trial
- Trial
- Elderberry Supplementation Reduces Cold Duration and Symptoms in Air-Travellers: A Randomized, Double-Blind Placebo-Controlled Clinical Trial.Nutrients · 2016Trial
- Relationship Between Hypovitaminosis C, Obesity, and Features of Metabolic Syndrome-A Narrative Review.Nutrition reviews · 2026Review
- Exploring the link between water-soluble vitamins and aging-associated immune system status.Frontiers in immunology · 2026Review
- Comparative effectiveness of oral nutritional supplements in preventing respiratory tract infections among adults: a systematic review and network meta-analysis.EClinicalMedicine · 2025Article
- Immunomodulatory Effects of Vitamin D and Zinc on Viral Infection.Biological trace element research · 2025Review
- Circulating micronutrient levels and respiratory infection susceptibility and severity: a bidirectional Mendelian randomization analysis.Frontiers in nutrition · 2024Article
- Subclinical Vitamin C Plasma Levels Associated with Increased Risk of CAD Diagnosis via Inflammation: Results from the NHANES 2003-2006 Surveys.Nutrients · 2023Article
- The Role of Some Vitamins in Respiratory-related Viral Infections: A Narrative Review.Clinical nutrition research · 2023Review
- Association of vitamin and/or nutritional supplements with fall among patients with diabetes: A prospective study based on ACCORD and UK Biobank.Frontiers in nutrition · 2022Article
- Nutritional risk factors for SARS-CoV-2 infection: a prospective study within the NutriNet-Santé cohort.BMC medicine · 2021Article
- Vitamin C supplementation is necessary for patients with coronavirus disease: An ultra-high-performance liquid chromatography-tandem mass spectrometry finding.Journal of pharmaceutical and biomedical analysis · 2021Observational
- Low level of Vitamin C and dysregulation of Vitamin C transporter might be involved in the severity of COVID-19 Infection.Aging and disease · 2021Article
- Opinions on the current pandemic of COVID-19: Use functional food to boost our immune functions.Journal of infection and public health · 2020Review
- Article
- The Role of Micronutrients in Support of the Immune Response against Viral Infections.Nutrients · 2020Review
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
3 authors at 2 institutions in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
The early indications of vitamin C deficiency are unremarkable (fatigue, malaise, depression) and may manifest as a reduced desire to be physically active; moreover, hypovitaminosis C may be associated with increased cold duration and severity. This study examined the impact of vitamin C on physical activity and respiratory tract infections during the peak of the cold season. Healthy non-smoking adult men (18-35 years; BMI < 34 kg/m2; plasma vitamin C < 45 µmol/L) received either 1000 mg of vitamin C daily (n = 15) or placebo (n = 13) in a randomized, double-blind, eight-week trial. All participants completed the Wisconsin Upper Respiratory Symptom Survey-21 daily and the Godin Leisure-Time Exercise Questionnaire weekly. In the final two weeks of the trial, the physical activity score rose modestly for the vitamin C group vs. placebo after adjusting for baseline values: +39.6% (95% CI [-4.5,83.7]; p = 0.10). The number of participants reporting cold episodes was 7 and 11 for the vitamin C and placebo groups respectively during the eight-week trial (RR = 0.55; 95% CI [0.33,0.94]; p = 0.04) and cold duration was reduced 59% in the vitamin C versus placebo groups (-3.2 days; 95% CI [-7.0,0.6]; p = 0.06). These data suggest measurable health advantages associated with vitamin C supplementation in a population with adequate-to-low vitamin C status.
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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.