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California Grape Powder for Gut and Heart Health in Overweight Adults

This study is looking at how freeze-dried grape powder affects gut health and heart health in overweight men and women aged 45 to 70. Researchers want to see if daily intake of this grape powder changes the bacteria in your gut (gut microbiome composition) and how well your gut lining works (intestinal permeability). They will also check if these changes are linked to improvements in inflammation and blood vessel function (arterial stiffness, blood pressure). You would receive either the grape powder or a placebo powder, then switch to the other after a break. The study is currently unclear on its recruitment status.

Study design
This is an interventional study planning to enroll 40 participants. It is designed as a crossover study, meaning you will receive both the active grape powder and a placebo at different times.
What's involved
You would consume 48 grams of powder dissolved in water twice daily for 3 weeks, followed by a 3-4 week break, and then switch to the other powder for another 3 weeks. You will have measurements taken at the beginning and end of each 3-week period, including blood and stool samples.
Compensation
Not stated in the trial record.
Follow-up
Measurements will be taken at Baseline, Week 3, and Week 9 to track changes in arterial stiffness, blood pressure, and gut microbiome composition.

AI-generated from the public study record. Only the study team can confirm whether you're eligible — confirm details with them before making decisions.

NCT06544954

Prebiotic Effects of California Grapes on Gut Health and Cardiometabolic Health in Overweight Men and Women

Recruiting
NAAges 45–70InterventionalPrevention
University of California, Davis
~40 participants
Updated 2026-04-13 on ClinicalTrials.gov
What's tested:Freeze-dried grape powderPlacebo powder

At a glance

Recruiting sites
1 of 1 listed site is recruiting right now
RecruitingSuspended, closed, or not yet open
What they're measuring
Arterial stiffness Change from Baseline
Measured over Baseline (Visit 1), Week 3 (Visit 2), Week 9 (Visit 4)
+5 more outcomes measured

Conditions

Arterial Stiffness
Blood Pressure
Dysbiosis
Inflammation
Permeability; Increased

Explore related trials

Metabolic SyndromeType 2 Diabetes Mellitus

Where it's being run

1 sites across 1 states
California1

Who to contact

Dragan Milenkovic, PhD
[email protected]
(530) 219-5872
Email the study team

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Do you actually qualify for this trial?

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Eligibility criteria

Inclusion

post-menopausal women (cessation of menstruation for minimum two years)
overweight and obese (BMI between 25-35 kg/m2)
stable treatment for type 2 diabetes or metabolic syndrome
ability to understand the intervention concept and written consent to participate
willingness to accept randomization, undergo testing and intervention procedures, and deliver stool and blood samples

Exclusion

menopausal hormone replacement therapy started within less than 6 months
antibiotics, prebiotics within last 3 months
antidiabetic treatment involving insulin (for type 1 diabetes)
vegetarian/vegan and not able to follow modified diet
any serious medical condition including but not limited to coronary artery disease, uncontrolled hypertension, stroke, congestive heart failure, insulin-dependent diabetes, liver disease, active cancer and anemia
psychiatric disease that interferes with the understanding and implementation of the intervention
history of eating disorders such as bulimia nervosa, anorexia nervosa, severe binge eating disorder in the last 5 years
history of substance abuse or alcohol abuse
involvement in a weight loss intervention program (including anti-obesity medication) within last 3 months or have had bariatric surgery
current smokers (within last 180 days)
use of dietary supplements containing polyphenols in the past 1 month
strenuous exercise greater than 10 hours per week

What this trial measures

  • Arterial stiffness Change from BaselineBaseline (Visit 1), Week 3 (Visit 2), Week 9 (Visit 4)

    Pulse Wave Velocity (PWV) from carotid to femoral artery after 5 minutes rest; PWV is an established index of aortic stiffness using a validated non-invasive device that allows online pulse wave recording and automatic PWV calculation

  • Blood pressure Change from BaselineBaseline (Visit 1), Week 3 (Visit 2), Week 9 (Visit 4)

    Average of latter 2 of 3 total measures (5 minutes apart) after 15 minutes of rest in a quiet room; SphygmoCor XCEL device will be used with participants in the seated position

  • Gut microbiome composition Change from BaselineBaseline (Visit 1), Week 3 (Visit 2), Week 9 (Visit 4)

    16S rRNA sequencing of stool samples collected by participants from home in fecal collection tubes filled with DNA/RNA shield

  • Gut permeability markers Change from BaselineBaseline (Visit 1), Week 3 (Visit 2), Week 9 (Visit 4)

    ELISA (zonulin, LPS, LBP, sCD14, DAO) to assay fasted blood samples collected when participants visit the clinic

  • Systemic inflammatory markers Change from BaselineBaseline (Visit 1), Week 3 (Visit 2), Week 9 (Visit 4)

    Luminex - Th17 inflammatory cytokines of fasted blood samples collected when participants visit the clinic

  • Lipid and metabolic profiles Change from BaselineBaseline (Visit 1), Week 3 (Visit 2), Week 9 (Visit 4)

    Lipid panel, comprehensive metabolic panel of fasted blood samples collected when participants visit the clinic