Grapes for Gut and Heart Health

(CALGRAM Trial)

Recruiting in Palo Alto (17 mi)

Age: 18+

Sex: Any

Travel: May Be Covered

Time Reimbursement: Varies

Trial Phase: Academic

Recruiting

Sponsor: University of California, Davis

No Placebo Group

Trial Summary

What is the purpose of this trial?

The goal of this clinical trial is to assess the impact of table grape consumption on gut microbiome, intestinal permeability, systemic inflammation, and vascular function in healthy overweight men and women aged 45-70 years. The main questions it aims to answer are: * Does daily grape intake alter intestinal microbiome composition and intestinal permeability? * Are changes in gut microbiota and intestinal permeability correlated with changes in cardiometabolic risk factors (inflammation, vascular function, lipid profiles)? * Does response to grape intake on gut microbiota, intestinal permeability, cardiometabolic and inflammatory markers differ between men and women? * Are metabolic pathways modified by grape consumption able to explain the link between gut health and cardiometabolic factors? Researchers will compare freeze-dried grape powder to placebo powder to see if grape powder improves cardiometabolic risk factors. Participants will * Consume the powder dissolved in water twice daily for 3 weeks * Follow their usual diet, modified to limit polyphenol-rich foods * Visit the clinic at the beginning and end of the intervention for vascular measurements and blood sample collection * Complete a 3-day 24-hour dietary recall and collect stool sample before each visit

Research Team

Eligibility Criteria

This trial is for healthy overweight men and women aged 45-70 who want to explore the health benefits of grape powder on gut and heart health. Participants should not have major health issues but may have concerns like high blood pressure or arterial stiffness. They must be willing to consume a test product daily and follow their usual diet with some restrictions.

Inclusion Criteria

I am willing to be randomly assigned to a treatment group, undergo tests, and provide stool and blood samples.

Overweight (BMI between 25-30 kg/m2)

Ability to understand the intervention concept and written consent to participate

Exclusion Criteria

I do not have any serious medical conditions like heart disease, uncontrolled high blood pressure, diabetes, liver disease, or active cancer.

I have not used hormone replacement, antibiotics, or prebiotics in the last 3 months.

I am taking medication to lower my cholesterol.

Trial Timeline

Screening

Participants are screened for eligibility to participate in the trial

1 week

1 visit (in-person)

Run-in

Participants limit intake of grapes and other polyphenol-rich foods while following their usual diet

1 week

Treatment

Participants consume 48 grams of freeze-dried grape powder or placebo dissolved in water twice daily

3 weeks

2 visits (in-person)

Washout

Participants undergo a washout period before crossover to the other intervention

3-4 weeks

Crossover Treatment

Participants switch to the alternate intervention (grape or placebo) for 3 weeks

3 weeks

2 visits (in-person)

Follow-up

Participants are monitored for safety and effectiveness after treatment

4 weeks

Treatment Details

Interventions

• Freeze-dried grape powder (Prebiotic)
• Placebo powder (Nutritional Intervention)

Trial Overview Researchers are testing if consuming freeze-dried grape powder can improve gut microbiome, intestinal permeability, inflammation levels, and vascular function compared to a placebo. The study involves taking the powder dissolved in water twice daily for four weeks while maintaining a normal diet with limited polyphenol-rich foods.

Participant Groups

Group I: Placebo, Then Grape Experimental Treatment 2 Interventions

Participants consume 48 grams of placebo powder matching grape powder (dissolved into water) twice daily for 3 weeks. After a washout period of at least 3 weeks, participants then consume 48 grams of freeze-dried grape powder (dissolved into water) twice daily for 3 weeks.

Group II: Grape, Then Placebo Experimental Treatment 2 Interventions

Participants consume 48 grams of freeze-dried grape powder (dissolved into water) twice daily for 3 weeks. After a washout period of at least 3 weeks, participants then consume 48 grams of placebo powder matching grape powder (dissolved into water) twice daily for 3 weeks.

Who Is Running the Clinical Trial?

University of California, Davis

Lead Sponsor

Trials

958

Recruited

4,816,000+

Rakesh Dixit

University of California, Davis

Chief Executive Officer since 2024

PhD in Biochemistry and Molecular Biology from the University of California, Davis

Suresh Mahabhashyam

University of California, Davis

Chief Medical Officer since 2020

MD from Bangalore Medical College

California Table Grape Commission

Collaborator

Trials

8

Recruited

270+