Gut MicrobiomesNCT07797803
Grape Impact on Human Gut Microbiome
A study testing Grape Powder in people with Gut Microbiomes, run by Icahn School of Medicine at Mount Sinai at 1 site in United States.
Trial summary
This is a bio-specimen analysis and dietary intervention study that will examine whether the daily consumption of California table grape powder significantly modulates the gut microbiome and systemic immune profiles in healthy adults. Read more about this study
- Who is it for?
- Ages 45 to 65 yearsHealthy volunteers can take part
- Conditions the study is for
- Gut Microbiomes
- What is being tested?
- Grape Powder
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 40 participants
- Where
- 1 siteUnited States
- Study dates
- Oct 2026to Feb 2027
- 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 45 to 65 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Healthy adults between the ages of 45 and 65 years old
- Body Mass Index (BMI) within the range of 18.5 to 25.9 kg/m²
- Willing and able to provide informed consent
- Agreement to maintain usual dietary patterns throughout the study, except for the provided study powder
- Agreement to avoid exclusion criteria (below) during the study period
- Able and willing to collect and mail a stool sample during the microbiome screening phase and, if enrolled in the intervention phase, and at the three defined study timepoints
- For enrollment into the intervention phase, meeting pre-specified microbiome eligibility criteria based on the screening stool sample, as defined in the study protocol.
Who cannot join
- Antibiotic use within 6 months prior to enrollment, or any planned antibiotic use during the study
- Recent initiation of or dose change in any medication or supplement within 3 months prior to enrollment, or planned initiation or dose change during the study
- Initiation or change of probiotic, prebiotic, or synbiotic supplements during the study. Existing long-term stable probiotic use is permitted
- Current or recent (within 3 months) systemic corticosteroid, biologic, DMARD, chemotherapy, or other immunosuppressive therapy; regular NSAID use (more than 2 doses per week); or planned initiation of any of the above during the study
- Active inflammatory bowel disease, irritable bowel syndrome with current symptoms, celiac disease, microscopic colitis, active diverticulitis, or acute gastrointestinal infection within 3 months; any history of C. difficile infection; or prior bariatric surgery or bowel resection
- Uncontrolled or unstable chronic disease, including but not limited to uncontrolled diabetes (HbA1c >8%), chronic hepatitis B or C, cirrhosis, moderate-to-severe chronic kidney disease (eGFR <60), active or recent (within 5 years) malignancy, solid organ or bone marrow transplant, or uncontrolled cardiovascular or psychiatric illness
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- Planned major change in diet, physical activity, or lifestyle during the study period; recent significant weight change (>5% in 3 months); or current adherence to an extreme dietary pattern (strict vegan, ketogenic, carnivore, or very-low-carb) maintained for more than 3 months
- Habitual high polyphenol intake, including daily consumption of more than 2 servings of berries, more than 500 mL of red wine, more than 4 cups of tea, or regular consumption of pomegranate, grape juice, or dark chocolate more than 3 times per week, as assessed by screening food-frequency questionnaire
- Heavy alcohol use (more than 14 drinks per week), current tobacco use, or daily cannabis use
- Known grape allergy or sensitivity; pregnancy, planned pregnancy, or breastfeeding during the study; current participation in other interventional clinical trials; or any condition that, in the investigator's judgment, would compromise study participation, compliance, or data interpretation
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
Icahn School of Medicine at Mount Sinai
New York, New York, 10029
Gang Fang, PhD, 212-659-1570, gang.fang@mssm.edu
Edward A Mead, PhD, 212-659-6844, edward.mead@mssm.edu
About this study
Official title: High-Resolution Assessment of California Table Grape Consumption on the Human Gut Microbiome-Immune Axis
This is a bio-specimen analysis and dietary intervention study that will examine whether the daily consumption of California table grape powder significantly modulates the gut microbiome and systemic immune profiles in healthy adults. The primary objective is to characterize longitudinal changes in microbial strains, metabolites, and immune markers following a 4-week grape intervention compared to a placebo. Methods include a screening of up to 300 individuals to evaluate pre-specified microbiome eligibility criteria, followed by a randomized, double-blind, placebo-controlled, parallel-group design where up to 40 participants will provide fecal and blood samples for high-resolution metagenomic sequencing and LC-MS/MS metabolomics at baseline, mid-study, and post-washout. Participants who meet the microbiome screening and other study eligibility criteria may be invited to participate in the intervention phase; participation in the screening phase does not guarantee enrollment in the intervention phase.
Read the detailed description
The human gut microbiome consists of trillions of microorganisms that are essential to host metabolism, immune system regulation, and the maintenance of disease resistance. Recent findings indicate that dietary changes can rapidly and significantly alter the composition of these microbial communities, leading to substantial effects on the host's overall physiology. Foods rich in polyphenols are highly effective at modulating this environment because they possess selective antimicrobial properties and exert beneficial prebiotic effects on the resident microbiota.
Polyphenol-rich foods beneficially modulate the human gut microbiome with downstream metabolic and immune effects. California table grapes contain a complex mixture of phenolics, resveratrol, flavans, flavonols, and anthocyanins, making them ideal candidates for investigating gastrointestinal and immune health. However, previous grape-microbiome studies have been limited by small sample sizes (n=21-29), short durations (2 weeks), low-resolution microbiome technologies (16S profiling), and failure to measure corresponding inflammatory or immune biomarkers.
This project will first conduct a microbiome screening phase in up to 300 healthy adults to identify individuals who meet pre-specified microbiome and other study eligibility criteria. Eligible individuals may then be invited to participate in a rigorous, multi-omic pilot study using standardized freeze-dried grape powder to determine how daily grape consumption modulates the gut microbiome-immune axis in up to 40 healthy adults. The study team will employ state-of-the-art metagenomic sequencing to achieve high-resolution microbiome profiling; metabolomic analysis; and immune biomarker profiling to assess gastrointestinal inflammation.
Specific Aims
Overarching Goal: To build on our unique expertise in high-resolution microbiome analyses to conduct a rigorous, multi-omic pilot study determining how daily consumption of California table grape powder modulates the human gut microbiome-immune axis in healthy adults.
Hypothesis: Compared to a placebo, daily consumption of California table grape powder will beneficially modulate the gut microbiome by: (1) altering microbial composition; (2) shifting the fecal metabolome to increase grape-derived and microbial-derived anti-inflammatory compounds; and (3) reducing baseline biomarkers of gastrointestinal inflammation.
- Conditions
- Gut Microbiomes
- Being tested
- Grape Powder, Placebo Powder
- Keywords
- California Table Grapes, Third generation sequencing, anti-inflammation
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Grape PowderDietary supplement
72 g of grape powder for daily consumption for 28 days.
Placebo PowderOther
72 g of matching placebo for daily consumption for 28 days.
| Study group | Role | What they receive |
|---|---|---|
| Grape Powder | Experimental | Receive grape powder for consumption during intervention stage. Receives: Dietary Supplement: Grape Powder |
| Control | Placebo comparator | Receive placebo control powder for consumption during intervention stage. Receives: Other: Placebo Powder |
What is being measured
The primary outcome is the main question the study is designed to answer.
Long read sequencing
Sequencing DNA from fecal samples to identify bacteria. This will assess whether the grape powder induces a change in the abundance of beneficial species/decrease in harmful species, following treatment, compared to control. This will be quantitatively assessed via sequencing.
Measured: 3 collections at T0 (after 3 weeks of dietary control), at week 4 (after grape or placebo powder daily), and at week 8 (after 4 weeks of returning back to normal diet)
Secondary outcomes (4)
Fecal metabolites profile from LC-MS/MS
Fecal metabolites as measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS)
Measured: 3 collections at T0 (after 3 weeks of dietary control), at week 4 (after grape or placebo powder daily), and at week 8 (after 4 weeks of returning back to normal diet)
Fecal calprotectin level measured by ELISA
Fecal calprotectin as measured by ELISA. Elevated levels of calprotectin are a sensitive indicator of mucosal irritation.
Measured: 3 collections at T0 (after 3 weeks of dietary control), at week 4 (after grape or placebo powder daily), and at week 8 (after 4 weeks of returning back to normal diet)
Fecal albumin level measured by ELISA
Fecal albumin as measured by ELISA. Fecal albumin serves as a proxy for intestinal permeability, as its presence in the gut lumen suggests a leak across the epithelial barrier.
Measured: 3 collections at T0 (after 3 weeks of dietary control), at week 4 (after grape or placebo powder daily), and at week 8 (after 4 weeks of returning back to normal diet)
Fecal Lipocalin-2 measured by ELISA
Fecal Lipocalin-2 as measured by ELISA. Fecal Lipocalin-2 is produced by both epithelial and immune cells in response to bacterial stressors.
Measured: 3 collections at T0 (after 3 weeks of dietary control), at week 4 (after grape or placebo powder daily), and at week 8 (after 4 weeks of returning back to normal diet)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted1 Sep 2026
- Study startOct 2026 (estimated)
- Primary completionFeb 2027 (estimated)
- Study completionFeb 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Gut MicrobiomesStudies of the same condition, open and under way.
- More trials run by Icahn School of Medicine at Mount SinaiThe 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
- Parallel groups
- Model description
- Screen volunteers from fecal samples; select 40 and randomly assign 20 to grape powder intake, 20 to placebo powder intake. Collect fecal samples, screen for health markers.
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 40 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Icahn School of Medicine at Mount Sinai
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Gang Fang, Icahn School of Medicine at Mount Sinai
- Investigators
- Gang Fang, PhD, Principal investigator, Icahn School of Medicine at Mount Sinai
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07797803
- Sponsor's protocol ID
- STUDY-26-00544
- Other IDs
- IN300001209
- Status last verified
- Sep 2026
- First submitted
- 27 Aug 2026
- Last updated
- 24 Sep 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: All of the individual participant data collected during the trial, after deidentification.