The Effect of Vitamin C Supplementation on Gut Microbiota Composition and Function in Healthy Adults
For patients and families
In plain language
An automatic summary of structured registry data. It is an orientation aid, not a substitute for the official protocol or a physician assessment.
- What is being studied
- The protocol lists: Moderate Vitamin C dose (200 mg), High-dose vitamin C supplementation (1000 mg), Habitual diet (run in period).
- Who it may be relevant to
- Registry conditions: Short Chain Fatty Acids Concentration in Stools, Gut Microbiota Diversity and Composition. Basic parameters: 18 years — 65 years · All.
- What needs checking
- Age, condition and sex are only basic indicators. Prior treatment, laboratory values and other mandatory requirements appear in the eligibility criteria below.
- Where it takes place
- United Kingdom
- Next step
- Save the trial, show it to the treating physician, and confirm current recruitment with the study center. Costs, documents and travel →
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Official title
The Effect of Vitamin C Supplementation on Gut Microbiota Composition and Metabolic Activity in Healthy Adults
Overview
The aim of this dietary intervention study is to explore how vitamin C affects the bacteria that live in our gut. Vitamins are essential nutrients found in fruits and vegetables. Our bodies cannot make them on their own, but we need them to function correctly. Vitamins play various roles, including supporting the immune system and assisting with energy production. Some vitamins in our diet can reach the large intestine, where they may be used by gut bacteria to promote their growth. In this study, we aim to investigate how our gut bacteria interact with vitamin C and how this interaction affects their growth and activity. For this study, participants will follow their habitual diet for one-week (run-in period), followed by two consecutive two-week supplementation periods in which they will first take a moderate dose (200 mg/day) and then a high-dose (1000 mg/day) of vitamin C. A final one-week period follow up period will involve a return to their habitual diet. Faecal, blood and urine samples will be collected at the start and end of each supplementation period to explore changes in gut microbiota composition, activity and markers of inflammation.
Detailed description
This is a sequential dietary intervention trial exploring the effects of two doses of vitamin C supplementation on gut microbiota: a moderate, diet-achievable dose of 200 mg/day, and a high dose of 1000 mg/day, each given for two weeks. Primary outcomes will be gut microbiota activity (SCFA production) and composition while secondary exploratory outcomes will include systemic inflammation and gut barrier integrity markers. We anticipate that this pilot study will provide valuable insights into the dose-response effects of vitamin C and help define optimal intakes for promoting gut health.
Twenty-three healthy adults will be recruited from the Glasgow area, with all study visits taking place at the New Lister Building, University of Glasgow. Each participant will attend four study visits over six weeks.
The intervention includes:
* One-week run-in period (habitual diet) * Two weeks of moderate-dose vitamin C (Vitamin C Chewable Tablet 200 mg, one tablet per day) * Two weeks of high-dose vitamin C (Vitamin C Chewable Tablet 1000 mg, one tablet per day) * One-week follow-up (habitual diet)
There will be no washout period between the study periods and participants will be instructed to maintain their usual diet and lifestyle throughout the trial.
Hypothesis Vitamin C supplementation will increase stool SCFAs, particularly butyrate, and beneficially modulate gut microbiota composition, systemic inflammation and gut barrier integrity in healthy adults.
Study schedule and sample collection:
* Visit 1 (Week 0): Baseline anthropometric measurements will be taken (height, weight, body composition); stool and urine sample collection will be arranged. Participants will follow habitual diet for one week (run-in period). * Visit 2 (Week 1): Anthropometric measurements; stool sample, and fasted blood and urine samples will be collected. The participants will begin a moderate-dose vitamin C supplementation (Vitamin C Chewable Tablet 200mg, one tablet per day) for two weeks (moderate-dose period), in addition to their usual diet. * Visit 3 (Week 3): Anthropometric measurements; stool sample, and fasted blood and urine samples will be collected. The participants will switch to a high-dose vitamin C supplementation (Vitamin C Chewable Tablet 1000mg, one tablet per day) for two weeks (high-dose period), in addition to their usual diet. * Visit 4 (Week 5): Anthropometrics; stool sample, and fasted blood and urine samples will be collected. Participants will resume their habitual diet for one week (follow-up period). * Follow up (Week 6): Final stool sample collected.
Three-day food diaries, Gastrointestinal Symptoms Rating Scale (GSRS) diary, and compliance tick sheets will be completed during the run-in, moderate-dose, and high-dose periods.
Sample size The sample size is based on anticipated effects on stool butyrate, a key SCFA expected to be modified by the intervention. Based on literature and our group's previous results, recruiting 20 healthy participants would provide 80% power (P=0.05) to detect a mean change of 4 μmol/g in stool butyrate (SD: 4.5 μmol/g). Allowing for 15% drop-out, a total of 23 participants will ensure adequate power.
Interventions
- Dietary supplement Moderate Vitamin C dose (200 mg)
200 mg of vitamin C provided as a chewable tablet, taken orally daily for two weeks - Dietary supplement High-dose vitamin C supplementation (1000 mg)
1000 mg of Vitamin C provided as a chewable tablet, taken orally daily for two weeks - Other Habitual diet (run in period)
this is a run-in period where participants consume their habitual diet for one week
Primary outcome measures
- Butyrate (Short Chain Fatty Acid) [Time frame: Baseline (Visit 1), Week 1 (Visit 2), Week 3 (Visit 3), Week 5 (Visit 4) and Week 6 (Visit 5)]
- Short Chain Fatty Acids i.e. acetate, propionate, butyrate, total [Time frame: Baseline (Visit 1), Week 1 (Visit 2), Week 3 (Visit 3), Week 5 (Visit 4) and Week 6 (Visit 5)]
- Stool microbiota composition analysis [Time frame: Baseline (Visit 1), Week 1 (Visit 2), Week 3 (Visit 3), Week 5 (Visit 4) and Week 6 (Visit 5)]
Secondary outcome measures (3)
- Stool pH [Time frame: Baseline (Visit 1), Week 1 (Visit 2), Week 3 (Visit 3), Week 5 (Visit 4) and Week 6 (Visit 5)]
- Vitamin C in plasma [Time frame: Week 1 (Visit 2), Week 3 (Visit 3), and Week 5 (Visit 4)]
- Inflammatory markers [Time frame: Week 1 (Visit 2), Week 3 (Visit 3), and Week 5 (Visit 4)]
Eligibility criteria
Inclusion criteria
- Healthy individuals aged 18-65 years with a BMI between 18.5-35 Kg/m2
- Self-reported good health with no chronic conditions requiring regular medical care
- Willing to provide blood, urine, and stool samples at multiple time points
Exclusion criteria
- Aged <18 or >65 years
- Smoking
- Chronic illness requiring regular medication or GP visits
- Current or recent medication affecting gut transit or digestion
- Major gastrointestinal surgery
- Pregnant or breastfeeding
- Regular use of pre/probiotics, vitamins, or minerals (unless willing to discontinue 2-4 weeks prior)
- Antibiotics in past 3 months
- Weight change >±2 kg in past month
- Participation in other research likely to interfere with this study
Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.
Healthy volunteers: Yes
Study design
- Allocation
- Non-randomized
- Model
- Sequential
- Masking
- Open label
- Primary purpose
- Basic science
Study locations
United Kingdom · 1 center
- New Lister Building, Glasgow Royal Infirmary, 10-16 Alexandra Parade, G31 2ER — Glasgow
Identifiers
NCT: NCT07388121 · 200250024