Actively Recruiting
The Effect of Vitamin C Supplementation on Gut Microbiota Composition and Metabolic Activity in Healthy Adults
Led by University of Glasgow · Updated on 2026-02-04
23
Participants Needed
1
Research Sites
N/A
Total Duration
On this page
Sponsors
U
University of Glasgow
Lead Sponsor
P
Professor Konstantinos Gerasimidis, University of Glasgow
Collaborating Sponsor
AI-Summary
What this Trial Is About
This research aims to explore how vitamin C affects the bacteria living in the gut of healthy adults. Vitamins are essential nutrients that support various body functions, including the immune system and energy production. The study will investigate how gut bacteria interact with vitamin C and how this interaction influences their growth and activity, focusing on short-chain fatty acids and gut microbiota composition. Participants will follow their usual diet for one week, then take a moderate dose of vitamin C (200 mg daily) for two weeks, followed by a high dose (1000 mg daily) for another two weeks. After these supplementation periods, they will return to their habitual diet for one week. Vitamin C is provided as chewable tablets taken orally each day, and there is no washout period between phases. During the six-week study, participants will attend four study visits and a final follow-up stool sample collection. At each visit, measurements of body composition and collection of stool, blood, and urine samples will occur. Participants will complete food diaries, gastrointestinal symptom diaries, and compliance checklists. Researchers will measure gut microbiota activity, stool composition, vitamin C levels, inflammatory markers, and stool pH to understand the effects of vitamin C doses on gut health.
CONDITIONS
Brief Title
The Effect of Vitamin C Supplementation on Gut Microbiota Composition and Function in Healthy Adults
Who Can Participate
Eligibility Criteria
You may qualify if you...
- Healthy individuals aged 18 to 65 years with a BMI between 18.5 and 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
You will not qualify if you...
- Under 18 or over 65 years old
- Current smoker
- Chronic illness requiring regular medication or doctor visits
- Current or recent medication affecting gut transit or digestion
- History of major gastrointestinal surgery
- Pregnant or breastfeeding
- Regular use of prebiotics, probiotics, vitamins, or minerals unless willing to stop 2-4 weeks before study
- Antibiotics taken in the past 3 months
- Weight change greater than ±2 kg in the past month
- Participation in other research likely to interfere with this study
AI-Screening
AI-Powered Screening
Complete this quick 3-step screening to check your eligibility
Your Study Journey
Duration - 2 to 4 weeks
Participants are screened for eligibility to participate in the trial.
1 screening and enrollment visit (in-person)
Duration - 1 week
Participants follow their usual habitual diet while baseline measurements and sample collections are taken.
1 visit at the start of the run-in period (in-person)
Duration - 2 weeks
Participants take a moderate dose of 200 mg vitamin C daily for two weeks while continuing their usual diet. Samples and measurements are collected at the start and end of this period.
2 visits (Week 1 and Week 3, in-person)
Duration - 2 weeks
Participants take a high dose of 1000 mg vitamin C daily for two weeks while continuing their usual diet. Samples and measurements are collected at the start and end of this period.
2 visits (Week 3 and Week 5, in-person)
Duration - 1 week
Participants resume their habitual diet without vitamin C supplementation. Final sample collection is done to observe any lasting effects.
1 visit for sample collection (Week 6, in-person)
Trial Site Locations
Total: 1 location
1
New Lister Building, Glasgow Royal Infirmary, 10-16 Alexandra Parade, G31 2ER
Glasgow, United Kingdom, G31 2ER
Actively Recruiting
Research Team
R
Raihana Halim
How is the study designed?
Study Type
INTERVENTIONAL
Masking
NONE
Allocation
NON_RANDOMIZED
Model
SEQUENTIAL
Primary Purpose
BASIC_SCIENCE
Number of Arms
1
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