Grape powder effects on gut and immune health in adults with obesity

Effects of Grape Consumption on Immune and Gut Health in the Setting of Obesity

NA · University of Missouri-Columbia · NCT07231484

This 12-week test will see if taking 48 g per day of freeze-dried grape powder changes the gut microbiome and immune markers in adults aged 30–45 with obesity.

Quick facts

PhaseNA
Study typeInterventional
Enrollment50 (estimated)
Ages30 Years to 45 Years
SexAll
SponsorUniversity of Missouri-Columbia (other)
Locations1 site (Columbia, Missouri)
Trial IDNCT07231484 on ClinicalTrials.gov

What this trial studies

This is a 12-week randomized, controlled crossover design in which each participant receives both the grape powder and an isocaloric placebo in different periods. Participants are randomized to consume 48 g/day of whole freeze-dried grape powder for 4 weeks followed by a 4-week washout and 4 weeks of placebo, or the placebo first followed by the grape powder. Stool, blood, and clinical measures will be collected to measure changes in the gut microbiome and immune-related markers. The trial enrolls weight-stable adults aged 30–45 with BMI 30–45 kg/m2 at the University of Missouri–Columbia.

Who should consider this trial

Good fit: Ideal candidates are adults aged 30–45 with BMI 30–45 kg/m2 who are weight-stable, non-smokers, not recently using antibiotics or immune-modifying medications, and willing to consume the study foods and attend in-person visits.

Not a fit: People with diabetes, active gastrointestinal disease, recent antibiotic/probiotic use, pregnancy or lactation, HIV, or current use of immune- or metabolism-altering medications are unlikely to benefit or be eligible.

Why it matters

Potential benefit: If successful, the grape powder could offer a simple dietary approach to improve gut microbiome balance and immune-related markers in people with obesity.

How similar studies have performed: Previous animal studies and small human trials of grape polyphenols and other fruit-derived phytochemicals have shown changes in the microbiome or immune markers, but results in people with obesity are limited and mixed.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Age: 30-45 years
* Obesity with BMI of 30-45 kg/m2
* Willingness to consume study foods
* Consistent diet and activity patterns for 4 weeks
* Weight stable (\<5kg change over last 3 months)
* Non-smoker \> 1 year or more
* Not currently consuming an extremely healthy diet

Exclusion Criteria:

* Study food allergies
* Regular consumption of grapes or grape-derived products
* Gastrointestinal disease and/or bariatric surgery
* Uncontrolled hypertension and blood pressure \>180/110
* Diabetes
* Clinical Depression
* Illicit drug use
* History of alcohol or drug abuse
* Recent use of medications that affect immune function (e.g., corticosteroids)
* Recent consumption of antibiotics, prebiotics, probiotics, symbiotics, or dietary supplements containing fiber or phytochemicals
* Pregnant or lactating individuals
* HIV positivity
* Recent start of medications that affect metabolism or appetite
* Drug therapy for coronary artery disease, peripheral artery disease, congestive heart failure, or dyslipidemia

Where this trial is running

Columbia, Missouri

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.

View on ClinicalTrials.gov →

Conditions: Obesity &Amp, Overweight, Obesity, Immunity, Microbiome, Gut, Grape, Stress

Last reviewed 2026-05-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.