Effects of Grape Consumption on the Immune-Gut Axis in Obesity

July 30, 2026 updated by: Jaapna Dhillon, University of Missouri-Columbia

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

This study is investigating the benefits of whole freeze-dried grape powder consumption on the immune-gut axis in adults with obesity.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

The study is a 12-wk randomized, controlled, crossover trial. Participants will be randomized to one of two intervention sequences, either consuming 48g/day of whole freeze-dried grape powder followed by an isocaloric placebo powder or consuming the placebo powder followed by the whole freeze-dried grape powder. Active intervention phases will be 4 weeks in duration followed by a 4-week washout period between treatments.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
50

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

  • United States
    • Missouri
      • Columbia, Missouri, United States, 65211
        • Recruiting
        • University of Missouri-Columbia
        • Principal Investigator:
          • Jaapna Dhillon, PhD
        • Sub-Investigator:
          • Caitlyn Winn, MS
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Age: 18-60 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
  • 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

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Sequence 1: Grape then Placebo
Whole freeze-dried grape powder for 4 weeks, 4-week washout, then isocaloric placebo powder for 4 weeks.
Other: Freeze-dried grape powder
48 g/day oral consumption during the 4-week active period.
Other: Placebo powder
Isocaloric placebo matched to grape powder; oral consumption during the 4-week active period.
Experimental: Sequence 2: Placebo then Grape
Isocaloric placebo powder for 4 weeks, 4-week washout, then whole freeze-dried grape powder for 4 weeks.
Other: Freeze-dried grape powder
48 g/day oral consumption during the 4-week active period.
Other: Placebo powder
Isocaloric placebo matched to grape powder; oral consumption during the 4-week active period.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Gut microbial diversity
Time Frame: Baseline, Week 4, Week 8, Week 12
Assessed via 16s rRNA sequencing
Baseline, Week 4, Week 8, Week 12
LPS-binding protein concentration
Time Frame: Baseline, Week 4, Week 8, Week 12
Intestinal permeability marker
Baseline, Week 4, Week 8, Week 12
Cytokine concentrations following PBMC stimulation
Time Frame: Baseline, Week 4, Week 12
IL-6, IL-10
Baseline, Week 4, Week 12
Perceived stress score
Time Frame: Baseline, Week 4, Week 8, Week 12
Assessed using validated Cohen's Perceived Stress Scale. Scores range from 0-56 with higher scores indicating greater stress perceptions.
Baseline, Week 4, Week 8, Week 12

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Gut microbiome abundance
Time Frame: Baseline, Week 4, Week 8, Week 12
Assessed via 16s rRNA sequencing
Baseline, Week 4, Week 8, Week 12
Inflammatory Markers
Time Frame: Baseline, Week 4, Week 8, Week 12
IL-6, IL-10, TNF-alpha, IFN-gamma
Baseline, Week 4, Week 8, Week 12
Body mass
Time Frame: Baseline, Week 4, Week 8, Week 12
Measured in kg
Baseline, Week 4, Week 8, Week 12
Body composition
Time Frame: Baseline, Week 4, Week 8, Week 12
Fat mass and fat-free mass
Baseline, Week 4, Week 8, Week 12
Anthropometrics
Time Frame: Baseline, Week 4, Week 8, Week 12
Waist circumference, hip circumference, thigh circumference
Baseline, Week 4, Week 8, Week 12
Glucoregulation
Time Frame: Baseline, Week 4, Week 8, Week 12
Fasting glucose concentrations
Baseline, Week 4, Week 8, Week 12
Insulinemic biomarker concentrations
Time Frame: Baseline, Week 4, Week 8, Week 12
Insulin concentrations
Baseline, Week 4, Week 8, Week 12
Lipid profile
Time Frame: Baseline, Week 4, Week 8, Week 12
LDL, HDL, triglycerides, total cholesterol
Baseline, Week 4, Week 8, Week 12
Blood pressure
Time Frame: Baseline, Week 4, Week 8, Week 12
Diastolic and systolic blood pressure
Baseline, Week 4, Week 8, Week 12
Dietary intake using 24-hour recalls
Time Frame: Every week
24-hour diet recall using Automated Self-Administered 24-Hour Dietary Assessment Tool (ASA-24).
Every week
Physical activity
Time Frame: Baseline, Week 4, Week 8, Week 12
Activity assessment using Actigraphs
Baseline, Week 4, Week 8, Week 12
Sleep indices from Actigraphs
Time Frame: Baseline, Week 4, Week 8, Week 12
Assessed using Actigraphs
Baseline, Week 4, Week 8, Week 12
24-hour appetite ratings
Time Frame: Baseline, Week 4, Week 8, Week 12
24-hour appetite ratings assessed using Visual Analog Scale. For each question scores range from 0-100 with higher scores indicating "extremely" and lower scores indicating "not at all."
Baseline, Week 4, Week 8, Week 12
Palatability rating of foods
Time Frame: Every week
Hedonic general labelled magnitude scale (gLMS). Scores range from 0 to 100.
Every week
Acceptance rating of foods
Time Frame: Every week
9-point food action rating scale (1-9) with higher scores indicating a higher food rating.
Every week
Dietary Intake over past month
Time Frame: Baseline, Week 4, Week 8, Week 12
Assessed using Food Frequency Questionnaires
Baseline, Week 4, Week 8, Week 12
IPAQ Score
Time Frame: Baseline, Week 4, Week 8, Week 12
Measured using the International Physical Activity Questionnaire (IPAQ). Activity levels categorized as high, moderate, or low based on IPAQ scoring procedure.
Baseline, Week 4, Week 8, Week 12
Sleep indices from sleep diary
Time Frame: Baseline, Week 4, Week 8, Week 12
Assessed using sleep diary
Baseline, Week 4, Week 8, Week 12

Other Outcome Measures

Other Outcome Measures

For clinical trials, a planned measurement described in the protocol that is used to determine the effect of an intervention/treatment on participants. For observational studies, a measurement or observation that is used to describe patterns of diseases or traits, or associations with exposures, risk factors, or treatment. Types of outcome measures include primary outcome measure and secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Memory indices
Time Frame: Baseline, Week 4, Week 8, Week 12
Assessed using memory tests
Baseline, Week 4, Week 8, Week 12
Attention indices
Time Frame: Baseline, Week 4, Week 8, Week 12
Assessed using d2 test of attention
Baseline, Week 4, Week 8, Week 12

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University of Missouri-Columbia

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
California Table Grape Commission

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
December 19, 2025

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 20, 2027

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 30, 2027

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
September 15, 2025

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
November 13, 2025

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
November 17, 2025

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
July 31, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 30, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
July 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 2128808

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

Individual participant data that underlie the results reported here after deidentification (ie; text, tables, figures, and appendices)

IPD Sharing Time Frame

Immediately following publication. No end date.

IPD Sharing Access Criteria

Data will be deposited in online repositories

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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