How vitamin C affects gut bacteria and their activity in healthy adults

Is this trial a fit for you?

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

This sequential dietary intervention recruits 23 healthy adults in Glasgow who will follow their habitual diet for one week, then take 200 mg/day vitamin C for two weeks followed immediately by 1000 mg/day for two weeks, with a final one-week follow-up. Stool, blood, and urine samples will be collected at four visits to measure gut microbiota composition and short-chain fatty acid (SCFA) production as primary outcomes, with exploratory measures of systemic inflammation and gut barrier integrity. Participants will be instructed to maintain their usual diet and lifestyle and there is no washout period between dosing phases. All visits take place at the New Lister Building, University of Glasgow.

Why it matters

Who can join: the full rules

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

Where it's running

• New Lister Building, Glasgow Royal Infirmary, 10-16 Alexandra Parade, G31 2ER
  Glasgow, United Kingdom Recruiting

Study contacts

• Principal investigator: Athanasios Koutsos, PhD — Human Nutrition, School of Medicine, College of Medical, Veterinary, and Life Sciences, University of Glasgow
• Study coordinator: Raihana Halim
• Email: 2859495H@student.gla.ac.uk
• Phone: 07857 725347

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How to take part

1. Review the eligibility criteria above with your treating physician.
2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.