Anti-inflammatory Activities of Vitamin C Supplementation on the Gut Barrier Function in Adults With Obesity
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: Vitamin C Supplement + Low Vitamin C Diet, Placebo + Low Vitamin C Diet.
- Who it may be relevant to
- Registry conditions: Adequate Vitamin C Status, Inadequate Vitamin C Status. Basic parameters: 18 years — 50 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 States
- Next step
- Save the trial, show it to the treating physician, and confirm current recruitment with the study center. Costs, documents and travel →
Unsure about the terms? Read our patient guide →
Overview
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.
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.
Interventions
- Dietary supplement Vitamin C Supplement + Low Vitamin C Diet
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. - Dietary supplement Placebo + Low Vitamin C Diet
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.
Primary outcome measures
- Small Intestinal Permeability [Time frame: Between-treatment arm comparison on day 14 following 2-week intervention.]
Secondary outcome measures (12)
- Large Intestinal Permeability [Time frame: Between-treatment arm comparison on day 14 following 2-week intervention.]
- Plasma Vitamin C [Time frame: Between-treatment arm comparison on day 14 following 2-week intervention.]
- Plasma Vitamin C [Time frame: Within-treatment arm comparison from day 0 to day 14 following 2-week intervention.]
- Fecal Calprotectin [Time frame: Between-treatment arm comparison on day 14 following 2-week intervention.]
- Fecal Myeloperoxidase [Time frame: Between-treatment arm comparison on day 14 following 2-week intervention.]
- Fecal Butyrate [Time frame: Between-treatment arm comparison on day 14 following 2-week intervention.]
- Fecal Proprionate [Time frame: Between-treatment arm comparison on day 14 following 2-week intervention.]
- Fecal Acetate [Time frame: Between-treatment arm comparison on day 14 following 2-week intervention.]
- Serum Endotoxin Concentration [Time frame: Between-treatment arm comparison on day 14 following 2-week intervention.]
- Plasma Lipopolysaccharide Binding Protein/Soluble Cluster of Differentiation-14 [Time frame: Between-treatment arm comparison on day 14 following 2-week intervention.]
- Plasma C-Reactive Protein [Time frame: Between-treatment arm comparison on day 14 following 2-week intervention.]
- Plasma Myeloperoxidase [Time frame: Between-treatment arm comparison on day 14 following 2-week intervention.]
Eligibility criteria
Inclusion criteria
- 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
Exclusion criteria
- 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
- 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).
Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.
Healthy volunteers: No
Study design
- Allocation
- Randomized
- Model
- Crossover
- Masking
- Triple blind
- Primary purpose
- Basic science
Study locations
United States · 1 center
- The Ohio State University — Columbus
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. PMID 30640128
Identifiers
NCT: NCT07151105 · STUDY20251283