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

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: Recruiting
• Conditions: Obesity &Amp; Overweight
• Intervention / Treatment: Other: Freeze-dried grape powder; Other: Placebo powder

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: Interventional
• Enrollment (Estimated): 50
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Jaapna Dhillon PhD, PhD; Phone Number: 573-884-2103; Email: jdhillon@health.missouri.edu
• Study Contact Backup: Name: Caitlyn Winn, MS; Phone Number: 207-210-8049; Email: cawq6x@umsystem.edu

Study Locations

• United States
  • Missouri
    • Columbia, Missouri, United States, 65211
      • Recruiting
      • University of Missouri-Columbia
      • Principal Investigator: Jaapna Dhillon, PhD
      • Contact: Caitlyn Winn, MS; Phone Number: 207-210-8049; Email: cawq6x@umsystem.edu
      • Sub-Investigator: Caitlyn Winn, MS

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

Description

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

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
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

Outcome Measure	Measure Description	Time Frame
Gut microbial diversity	Assessed via 16s rRNA sequencing	Baseline, Week 4, Week 8, Week 12
LPS-binding protein concentration	Intestinal permeability marker	Baseline, Week 4, Week 8, Week 12
Cytokine concentrations following PBMC stimulation	IL-6, IL-10	Baseline, Week 4, Week 12
Perceived stress score	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

Outcome Measure	Measure Description	Time Frame
Gut microbiome abundance	Assessed via 16s rRNA sequencing	Baseline, Week 4, Week 8, Week 12
Inflammatory Markers	IL-6, IL-10, TNF-alpha, IFN-gamma	Baseline, Week 4, Week 8, Week 12
Body mass	Measured in kg	Baseline, Week 4, Week 8, Week 12
Body composition	Fat mass and fat-free mass	Baseline, Week 4, Week 8, Week 12
Anthropometrics	Waist circumference, hip circumference, thigh circumference	Baseline, Week 4, Week 8, Week 12
Glucoregulation	Fasting glucose concentrations	Baseline, Week 4, Week 8, Week 12
Insulinemic biomarker concentrations	Insulin concentrations	Baseline, Week 4, Week 8, Week 12
Lipid profile	LDL, HDL, triglycerides, total cholesterol	Baseline, Week 4, Week 8, Week 12
Blood pressure	Diastolic and systolic blood pressure	Baseline, Week 4, Week 8, Week 12
Dietary intake using 24-hour recalls	24-hour diet recall using Automated Self-Administered 24-Hour Dietary Assessment Tool (ASA-24).	Every week
Physical activity	Activity assessment using Actigraphs	Baseline, Week 4, Week 8, Week 12
Sleep indices from Actigraphs	Assessed using Actigraphs	Baseline, Week 4, Week 8, Week 12
24-hour appetite ratings	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	Hedonic general labelled magnitude scale (gLMS). Scores range from 0 to 100.	Every week
Acceptance rating of foods	9-point food action rating scale (1-9) with higher scores indicating a higher food rating.	Every week
Dietary Intake over past month	Assessed using Food Frequency Questionnaires	Baseline, Week 4, Week 8, Week 12
IPAQ Score	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	Assessed using sleep diary	Baseline, Week 4, Week 8, Week 12

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Memory indices	Assessed using memory tests	Baseline, Week 4, Week 8, Week 12
Attention indices	Assessed using d2 test of attention	Baseline, Week 4, Week 8, Week 12

Collaborators and Investigators

• Sponsor: University of Missouri-Columbia
• Collaborators: California Table Grape Commission

Study record dates

Study Major Dates

• Study Start (Actual): December 19, 2025
• Primary Completion (Estimated): December 20, 2027
• Study Completion (Estimated): December 30, 2027

Study Registration Dates

• First Submitted: September 15, 2025
• First Submitted That Met QC Criteria: November 13, 2025
• First Posted (Estimated): November 17, 2025

Study Record Updates

• Last Update Posted (Actual): December 30, 2025
• Last Update Submitted That Met QC Criteria: December 22, 2025
• Last Verified: November 1, 2025

More Information

Terms related to this study

• Keywords: Obesity; Microbiome; Stress; Immunity; Gut; Grape
• Additional Relevant MeSH Terms: Nutrition Disorders; Overnutrition; Body Weight; Pathological Conditions, Signs and Symptoms; Nutritional and Metabolic Diseases; Signs and Symptoms; Overweight; Obesity
• Other Study ID 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