Effects of Grape Powder on Psychological Distress and Gut Microbiota in College Students

Effects of Grape Powder on Psychological Distress and Gut Microbiota in College Students (FTGP2025)

The goal of this trial is to investigate the effect of freeze-dried table grape powder (FTGP) on psychological distress and gut microbiota in college students. The main questions it aims to answer are:

Does FTGP reduce anxiety, depression, and perceived stress? Does FTGP improve the gut microbiota? Researchers will compare FTGP to a placebo to see how FTGP affects psychological distress and gut microbiota.

Participants will:

Drink a daily supplement containing FTGP or a placebo for 4 weeks. Record consumption of grape powder or placebo in a compliance log. Complete surveys and provide stool samples. Three in-person visits.

Study Overview

• Status: Active, not recruiting
• Conditions: Psychological Distress; Gut Microbiota
• Intervention / Treatment: Dietary supplement: freeze-dried table grape powder; Dietary supplement: Placebo

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

Contacts and Locations

Study Locations

• United States
  • New Jersey
    • New Brunswick, New Jersey, United States, 08901
      • Department of Biochemistry and Microbiology, School of Environmental and Biological Sciences, Rutgers, The State University of New Jersey

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Aged 18-30 years old
• Able to give written informed consent.
• BMI 18.5-24.9 kg/m2
• Healthy (self-reported)
• Can read and speak English

Exclusion Criteria:

• Currently taking medications that interfere with polyphenol
• Currently using or have used antibiotics continuously for >3 days within 3 months prior to enrollment
• Have had surgery involving the intestinal lumen within the last 30 days
• Have a documented diagnosis of celiac disease or/and inflammatory bowel diseases
• Are pregnant or breastfeeding
• Have prediabetes and diabetes
• Have had bariatric surgery
• Are immunocompromised ( e.g., cancer treatment, bone marrow/organ transplant, immune deficiency, or poorly controlled HIV/AIDS)
• Are unable to provide consent
• Are hospitalized,
• Have a history of or current alcohol, drug, or medication abuse (self-reported),
• Have contraindication to any substance in the investigational product or who are currently enrolled in other interventional trials

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: freeze-dried table grape powder (FTGP); Drink a daily supplement containing FTGP for 4 weeks	Dietary supplement: freeze-dried table grape powder; 48g freeze-dried table grape powder/day for 4 weeks
Placebo Comparator: Placebo; Drink a daily supplement containing a placebo for 4 weeks	Dietary supplement: Placebo; 48g placebo/day for 4 weeks

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Hamilton Anxiety Scale -14	HAMA-14 is one of the earliest and most widely used clinical scales for measuring the severity of a patient's anxiety. It has 14 items, each reflecting a cluster of anxiety symptoms. Total range: 0 to 56, with higher scores indicating greater severity of anxiety	baseline (1st), week 4 (2nd) and week 5 (3rd)
17-item of Hamilton Depression Rating Scale	HAMD-17 is one of the most widely used clinician-administered scales for measuring the severity of a patient's depression. It has 17 items, each covering symptoms of depression across mood, physical, and cognitive domains. With higher scores indicating greater severity of depression.	baseline (1st), week 4 (2nd) and week5 (3rd)
10-item of Perceived Stress Scale	PSS-10 is one of the most widely used psychological instruments for measuring the perception of stress. It has 10 items, each reflecting how unpredictable, uncontrollable, and overloaded respondents find their lives during the past month. Total range: 0 to 40, with higher scores indicating greater perceived stress.	baseline (1st), week 4 (2nd) and week5 (3rd)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Shannon Index of gut microbiota	Changes in gut microbiota will be assessed from stool samples using 16S rRNA gene sequencing. Alpha diversity will be calculated using Shannon Index. This measure will characterize whether the intervention alters gut microbial diversity in each subject.	baseline (1st), week 4 (2nd) and week5 (3rd)
Beta diversity of gut microbiota	Changes in gut microbiota will be assessed from stool samples using 16S rRNA gene sequencing. Beta diversity will be calculated using Bray Curtis distance between samples. This measure will characterize whether and how the intervention alters gut microbial communities.	baseline (1st), week 4 (2nd) and week 5 (3rd)
fecal short chain fatty acid	fecal short chain fatty acid will be measured by GC-MS	baseline (1st), week 4 (2nd) and week5 (3rd)

Collaborators and Investigators

• Sponsor: Rutgers, The State University of New Jersey
• Collaborators: California Table Grape Commission
• Investigators: Principal Investigator: Guojun Wu, Rutgers, The State University of New Jersey

Study record dates

Study Major Dates

• Study Start (Actual): October 20, 2025
• Primary Completion (Actual): December 24, 2025
• Study Completion (Estimated): May 30, 2026

Study Registration Dates

• First Submitted: October 1, 2025
• First Submitted That Met QC Criteria: October 7, 2025
• First Posted (Estimated): October 9, 2025

Study Record Updates

• Last Update Posted (Actual): January 15, 2026
• Last Update Submitted That Met QC Criteria: January 14, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Keywords: Gut Microbiota; psychological distress; Table grape
• Other Study ID Numbers: Pro2025001394

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: IPD might not be shared according to the consent form.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No