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NCT Number: NCT07231484

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

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

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Key information

Conditions

Obesity &Amp; Overweight Body Weight Nutrition Disorders Nutritional and Metabolic Diseases Obesity Overnutrition Overweight Pathological Conditions, Signs and Symptoms Signs and Symptoms

Age range

30 year–45 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

University of Missouri-Columbia

Columbia, Missouri, 65211, United States

Location status: Recruiting

Location contact

Caitlyn Winn, MS

CONTACT

[email protected]

207-210-8049

Caitlyn Winn, MS

SUB_INVESTIGATOR

Jaapna Dhillon, PhD

PRINCIPAL_INVESTIGATOR

About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Freeze-dried grape powder

Other

48 g/day oral consumption during the 4-week active period.

Placebo Powder

Other

Isocaloric placebo matched to grape powder; oral consumption during the 4-week active period.

Primary outcomes

  1. Gut microbial diversity

    Time frame: Baseline, Week 4, Week 8, Week 12

    Assessed via 16s rRNA sequencing

  2. LPS-binding protein concentration

    Time frame: Baseline, Week 4, Week 8, Week 12

    Intestinal permeability marker

  3. Cytokine concentrations following PBMC stimulation

    Time frame: Baseline, Week 4, Week 12

    IL-6, IL-10

  4. 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.

Secondary outcomes

  1. Gut microbiome abundance

    Time frame: Baseline, Week 4, Week 8, Week 12

    Assessed via 16s rRNA sequencing

  2. Inflammatory Markers

    Time frame: Baseline, Week 4, Week 8, Week 12

    IL-6, IL-10, TNF-alpha, IFN-gamma

  3. Body mass

    Time frame: Baseline, Week 4, Week 8, Week 12

    Measured in kg

  4. Body composition

    Time frame: Baseline, Week 4, Week 8, Week 12

    Fat mass and fat-free mass

  5. Anthropometrics

    Time frame: Baseline, Week 4, Week 8, Week 12

    Waist circumference, hip circumference, thigh circumference

  6. Glucoregulation

    Time frame: Baseline, Week 4, Week 8, Week 12

    Fasting glucose concentrations

  7. Insulinemic biomarker concentrations

    Time frame: Baseline, Week 4, Week 8, Week 12

    Insulin concentrations

  8. Lipid profile

    Time frame: Baseline, Week 4, Week 8, Week 12

    LDL, HDL, triglycerides, total cholesterol

  9. Blood pressure

    Time frame: Baseline, Week 4, Week 8, Week 12

    Diastolic and systolic blood pressure

  10. 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).

  11. Physical activity

    Time frame: Baseline, Week 4, Week 8, Week 12

    Activity assessment using Actigraphs

  12. Sleep indices from Actigraphs

    Time frame: Baseline, Week 4, Week 8, Week 12

    Assessed using Actigraphs

  13. 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."

  14. Palatability rating of foods

    Time frame: Every week

    Hedonic general labelled magnitude scale (gLMS). Scores range from 0 to 100.

  15. Acceptance rating of foods

    Time frame: Every week

    9-point food action rating scale (1-9) with higher scores indicating a higher food rating.

  16. Dietary Intake over past month

    Time frame: Baseline, Week 4, Week 8, Week 12

    Assessed using Food Frequency Questionnaires

  17. 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.

  18. Sleep indices from sleep diary

    Time frame: Baseline, Week 4, Week 8, Week 12

    Assessed using sleep diary

Other outcomes

  1. Memory indices

    Time frame: Baseline, Week 4, Week 8, Week 12

    Assessed using memory tests

  2. Attention indices

    Time frame: Baseline, Week 4, Week 8, Week 12

    Assessed using d2 test of attention

Study contacts

Contact information is provided by the study sponsor or research team.

Caitlyn Winn, MS

CONTACT

[email protected]

207-210-8049

Jaapna Dhillon PhD, PhD

CONTACT

[email protected]

573-884-2103

Sponsors and collaborators

Lead sponsor

University of Missouri-Columbia

Other

Collaborators

  • California Table Grape Commission

Registry information

Official study title

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

Important dates

Study start
2025
Primary completion
2027
Study completion
2027
First posted
Nov 17, 2025
Registry last updated
Dec 30, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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