Adequate Vitamin C StatusNCT07151105
Anti-inflammatory Activities of Vitamin C Supplementation on the Gut Barrier Function in Adults With Obesity
A study testing Vitamin C Supplement + Low Vitamin C Diet in people with Adequate Vitamin C Status and Inadequate Vitamin C Status, run by Ohio State University at 1 site in United States.
Trial summary
This study is testing whether taking vitamin C every day can help improve gut health and reduce inflammation in adults with obesity. Poor gut health-sometimes called "leaky gut"-can allow harmful substances from bacteria to enter the bloodstream, which may lead to inflammation and increase the risk of heart disease… Read more about this study
- Who is it for?
- Ages 18 to 50 years
- Conditions the study is for
- Adequate Vitamin C Status, Inadequate Vitamin C Status
- What is being tested?
- Vitamin C Supplement + Low Vitamin C Diet
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 34 participants
- Where
- 1 siteUnited States
- Study dates
- 1 Oct 2025to 30 Dec 2028
- Phase
- Interventional
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 50 years
- All sexes
- No healthy volunteers
- Adult
Who may be able to join
- English speaking
- Men and women between 18-50 years of age
- BMI 30-40 kg/m²
- Resting blood pressure <140/90 mm Hg
- No use of multivitamin/vitamin C supplement within past 1-month
- Non-vegetarian/non-vegan
- Willingness to follow a diet low in fruits and vegetables for two, 2-week periods
Who cannot join
- Current smoker or vaper, including tobacco, cannabis, or nicotine products
- Alcohol consumption >2 drinks/day
- Use of antibiotics within past 1-month
- Use of probiotic supplements within past 1-month
- Use of anti-inflammatory drugs within past 1-month
- Individuals with unmanaged or poorly controlled diabetes, dyslipidemia, hypertension
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- Known history of bleeding disorders, hemochromatosis, or kidney stones
- For Women: Pregnancy, lactation, or change in birth control within the past 3-months
- Use of certain medications that may interact with vitamin C, including blood thinners, some antiviral drugs (e.g., indinavir), and certain antipsychotic medications (e.g., fluphenazine).
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
The Ohio State University
Columbus, Ohio, 43210
About this study
This study is testing whether taking vitamin C every day can help improve gut health and reduce inflammation in adults with obesity. Poor gut health-sometimes called "leaky gut"-can allow harmful substances from bacteria to enter the bloodstream, which may lead to inflammation and increase the risk of heart disease and liver problems.
Participants will complete two study periods, each lasting two weeks, with a two-week break in between. In one period, they will take vitamin C; in the other, a placebo. During each period, researchers will collect blood, urine, and stool samples, ask participants to track their diet and activity, and perform a test to measure gut permeability.
There are minimal risks, such as discomfort from blood draws or temporary stomach upset from a sugar drink. While participants may not directly benefit, their involvement will help researchers learn whether vitamin C is a safe and effective way to improve gut health in people with obesity.
Read the detailed description
This clinical study aims to evaluate the impact of vitamin C supplementation on gut barrier function and systemic inflammation in adults with obesity. The research builds on preclinical findings that suggest vitamin C plays a critical role in maintaining gut integrity and reducing inflammation. Approximately 40% of Americans have suboptimal vitamin C status, with even higher prevalence among individuals with obesity.
The primary hypothesis is that improving vitamin C status through dietary supplementation will reduce intestinal permeability and metabolic endotoxemia. A secondary hypothesis is that vitamin C will also reduce biomarkers of intestinal inflammation and promote favorable changes in gut microbiota composition, including increased production of short-chain fatty acids (SCFAs), which are essential for intestinal health.
This randomized, double-blind, placebo-controlled crossover trial will enroll 34 obese adults (BMI 30-40 kg/m², aged 18-50 years). Participants will complete two 2-week intervention periods separated by a 2-week washout. In one period, they will receive vitamin C (500 mg capsules taken twice daily); in the other, a placebo. During both periods, participants will follow a low-vitamin C diet to minimize variability in circulating vitamin C levels.
Assessments will occur on Days 0, 7, and 14 of each intervention period and include: Anthropometric measurements; Resting blood pressure; Fasting blood samples; and 3-day food records. On Day 14 of each period, participants will: Provide a stool sample and Complete a gut permeability test using a non-digestible sugar probe solution followed by a 24-hour urine collection. After the first intervention period, participants will undergo a 2-week washout before repeating the procedures with the alternate supplement.
Primary Outcome: Intestinal permeability
Secondary Outcomes: Biomarkers of endotoxemia; Gut microbiota composition; Intestinal and circulating inflammation biomarkers; Plasma vitamin C concentrations; Fecal short-chain fatty acids.
- Being tested
- Vitamin C Supplement + Low Vitamin C Diet, Placebo + Low Vitamin C Diet
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Vitamin C Supplement + Low Vitamin C DietDietary supplement
Participants will receive a vitamin C supplement (1000 mg/d) while following a low vitamin C diet to achieve adequate vitamin C status in a blinded manner. This will be compared to participants receiving a placebo while following a low vitamin C diet that is expected to maintain inadequate vitamin C status.
Placebo + Low Vitamin C DietDietary supplement
Participants will receive a placebo while following a low vitamin C diet to achieve inadequate vitamin C status in a blinded manner. This will be compared to participants receiving a vitamin C supplement while following a low vitamin C diet that is expected to maintain adequate vitamin C status.
| Study group | Role | What they receive |
|---|---|---|
| Inadequate Vitamin C Status | Placebo comparator | Placebo + Low Vitamin C Diet Receives: Dietary Supplement: Placebo + Low Vitamin C Diet |
| Adequate Vitamin C Status | Experimental | Vitamin C Supplement + Low Vitamin C Diet Receives: Dietary Supplement: Vitamin C Supplement + Low Vitamin C Diet |
What is being measured
The primary outcome is the main question the study is designed to answer.
Small Intestinal Permeability
Urinary excretion ratio of lactulose/mannitol following oral ingestion of these sugar probes.
Measured: Between-treatment arm comparison on day 14 following 2-week intervention.
Secondary outcomes (14)
Large Intestinal Permeability
Urinary excretion ratio of sucralose/erythritol following oral ingestion of these sugar probes.
Measured: Between-treatment arm comparison on day 14 following 2-week intervention.
Plasma Vitamin C
Biochemical measures of Vitamin C
Measured: Between-treatment arm comparison on day 14 following 2-week intervention.
Plasma Vitamin C
Biochemical measures of Vitamin C
Measured: Within-treatment arm comparison from day 0 to day 14 following 2-week intervention.
Fecal Calprotectin
Biochemical measures of Calprotectin
Measured: Between-treatment arm comparison on day 14 following 2-week intervention.
Fecal Myeloperoxidase
Biochemical measures of Myeloperoxidase
Measured: Between-treatment arm comparison on day 14 following 2-week intervention.
Fecal Butyrate
Biochemical measures of Butyrate
Measured: Between-treatment arm comparison on day 14 following 2-week intervention.
Fecal Proprionate
Biochemical measures of Proprionate
Measured: Between-treatment arm comparison on day 14 following 2-week intervention.
Fecal Acetate
Biochemical measures of Acetate
Measured: Between-treatment arm comparison on day 14 following 2-week intervention.
Serum Endotoxin Concentration
Biochemical measure of circulating endotoxin concentration at fasting
Measured: Between-treatment arm comparison on day 14 following 2-week intervention.
Plasma Lipopolysaccharide Binding Protein/Soluble Cluster of Differentiation-14
Biochemical measures of Lipopolysaccharide Binding Protein/Soluble Cluster of Differentiation-14 at fasting, reported as a ratio of protein concentrations
Measured: Between-treatment arm comparison on day 14 following 2-week intervention.
Plasma C-Reactive Protein
Biochemical measures of C-Reactive Protein
Measured: Between-treatment arm comparison on day 14 following 2-week intervention.
Plasma Myeloperoxidase
Biochemical measures of Myeloperoxidase
Measured: Between-treatment arm comparison on day 14 following 2-week intervention.
Plasma Tumor Necrosis Factor-α
Biochemical measures of Tumor Necrosis Factor-α
Measured: Between-treatment arm comparison on day 14 following 2-week intervention.
Plasma Trimethylamine N-oxide
Biochemical measures of Trimethylamine N-oxide
Measured: Between-treatment arm comparison on day 14 following 2-week intervention.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted3 Sep 2025
- Study start1 Oct 2025
- Primary completion30 Dec 2027 (estimated)
- Study completion30 Dec 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Adequate Vitamin C StatusStudies of the same condition, open and under way.
- More trials run by Ohio State UniversityThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 34 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Ohio State University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Richard Bruno, Ohio State University
- Investigators
- Richard Bruno, PhD, RD, Principal investigator, Ohio State University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07151105
- Sponsor's protocol ID
- STUDY20251283
- Status last verified
- Aug 2026
- First submitted
- 27 Aug 2025
- Last updated
- 1 Sep 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Although no formal plan for sharing is established, data will be shared upon reasonable request and when in accordance with regulatory compliance considerations.
Publications
Traber MG, Buettner GR, Bruno RS. The relationship between vitamin C status, the gut-liver axis, and metabolic syndrome. Redox Biol. 2019 Feb;21:101091. doi: 10.1016/j.redox.2018.101091. Epub 2018 Dec 26.
PubMed 30640128