The Effect of Grape Consumption on Increasing the Good Bacteria in the Human Intestine

May 4, 2023 updated by: Zhaoping Li, University of California, Los Angeles

Effect of Grape Consumption on the Microbiome in Healthy Subjects: A Pilot Study

This pilot study will assess the ability of daily consumption of one dose (2 servings) of freeze-dried whole table grape powder, made from conventionally grown grapes to alter the composition of the bacteria that live in the intestines in healthy subjects. The grape powder contains 46g of individually quick frozen (IQF) grapes, which is equivalent to 252g fresh fruit. 20 subjects will will consume the beige diet for 4 weeks followed by one dose (two servings) of standardized Freeze-Dried Whole Table Grape Powder (46g) daily for 4 weeks. The primary objective of this pilot study is to determine changes in the gut microbiome. Stool samples will be collected at 4 and 8 weeks for bacterial DNA to determine changes in the bacteria that live in the intestines. You will be asked to avoid foods rich in polyphenols including dark chocolate and cocoa products, dried herbs, berries, coffee, tea, flaxseeds, nuts (chestnut, hazelnut), olive and artichoke for the duration of the study.

Study Overview

Status

Status

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

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 bacterial composition of the intestinal microbiome has been linked to the development of chronic diseases including obesity, metabolic syndrome, type II diabetes and heart disease. Grapes provide a rich source of polyphenols and fiber. It has been demonstrated in animal studies that fruits with high polyphenol content and fiber exhibit prebiotic effects leading to changes in the gut microbiome, decrease in symptoms of metabolic syndrome, improvement in insulin resistance and decrease in intestinal and systemic inflammation. Several human intervention studies have also been performed that demonstrated beneficial effects of high polyphenol fruits on the intestinal microbiome. No information is available about the effect of grape consumption on the gut microbiome. This proposed pilot study will assess the ability of consumption of two servings of grapes daily to alter the gut microbiome composition, leading to increased bile secretion, increased fecal cholesterol degradation/excretion, decreased plasma cholesterol and improved intestinal wellbeing in a free-living population. 20 subjects will consume the beige diet for 4 weeks followed by one dose (two servings) of standardized Freeze-Dried Whole Table Grape Powder (46g) daily for 4 weeks. The primary objective of this pilot study is to determine changes in the gut microbiome. Secondary outcome will be fecal bile and cholesterol and their metabolites, plasma cholesterol and intestinal wellbeing questionnaire at 4 and 8 weeks Stool samples will be collected at 4 and 8 weeks for sequencing of bacterial DNA to determine changes in the microbiota. Changes in fecal bile, cholesterol, and cholesterol metabolites will be analyzed by gas chromatography. The objective of the proposed pilot study is to determine whether intake of 2 servings of grapes per day will alter the intestinal microflora leading to an increase in intestinal cholesterol degradation, decreased plasma cholesterol and increased intestinal wellbeing. This project will provide novel preliminary data for future research studies and to develop new consumer messages on the gut health benefits of grapes. New consumer information about the health benefit of grapes will enhance the The California Table Grape industry domestic and export marketing programs and increase consumption of grapes.

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 (Actual)

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.
20

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 Locations

  • United States
    • California
      • Los Angeles, California, United States, 90024
        • UCLA Center for Human Nutrition

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

18 years to 55 years (Adult)

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Healthy human adults age 18-55 years old (females have to be premenopausal)
  • Typically consume low fiber/polyphenol diet (beige diet)

Exclusion Criteria:

  • Eating a high fiber/polyphenol diet or taking any medication or dietary supplement, which interfere with the absorption of polyphenols.
  • History of gastrointestinal surgery, diabetes mellitus on medications, or other serious medical condition, such as chronic hepatic or renal disease, bleeding disorder, congestive heart disease, chronic diarrhea disorders, myocardial infarction, coronary artery bypass graft, angioplasty within 6 months prior to screening, current diagnosis of uncontrolled hypertension (defined as systolic BP >160mmHg, diastolic BP > 95mmHg), active or chronic gastrointestinal disorders, bulimia, anorexia, laxative abuse, or endocrine diseases (except thyroid disease requiring medication) as indicated by medical history or routine physical examination.
  • Screening laboratory value outside of the laboratory normal range that is considered clinically significant for study participation by the investigator.
  • Is unable or unwilling to comply with the study protocol.
  • Using prebiotics, probiotics, yogurt, and/or any fiber supplements regularly
  • Allergy or sensitivity to grapes. Subjects will be excluded if there is a prior history of such sensitivity. Since these foods are commonly eaten and allergies are rare, subjects should be aware of this sensitivity prior to entering the study. To determine this, a positive affirmation by the subject of grape ingestion without incident will be requested.
  • Taking antibiotics or laxatives within the past 3 months
  • Allergy or sensitivity to grapes. Subjects will be excluded if there is a prior history of such sensitivity. Since these foods are commonly eaten and allergies are rare, subjects should be aware of this sensitivity prior to entering the study. To determine this, a positive history of grape ingestion without incident will be requested. In addition, any subject with a history of allergy or anaphylaxis of any kind will be excluded
  • Subjects with known allergy to food coloring dyes.
  • In the opinion of the study investigator, any subject who demonstrate a risk of non-compliance with study procedure, or one who cannot read, understand or complete study - related materials.

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: Prevention
  • Allocation: Non-Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

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.
Active Comparator: Table Grape
Subjects will consume 4 weeks of (two servings) of standardized Freeze-Dried Whole Table Grape Powder
Other: Table Grape Powder
Freeze Dried Whole Table Grape Powder
Placebo Comparator: Beige Diet
Subjects will consume 4 weeks of a beige diet (low in fiber and low in polyphenols)
Other: Beige Diet
Low Fiber, low polyphenol Diet

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
Change in intestinal microbiome composition
Time Frame: Baseline (week 0) to Week 8
Stool samples will be collected at week 4 and 8 of the intervention periods
Baseline (week 0) to Week 8

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
change in fecal cholesterol, cholesterol metabolites, and bile acids
Time Frame: Baseline (week 0) to Week 8
Stool samples will be collected at week 4 and 8 of the intervention periods
Baseline (week 0) to Week 8
change in blood total cholesterol, LDL and HDL-cholesterol,
Time Frame: Baseline (week 0) to Week 8
Total cholesterol in blood will be analyzed spectrophotometrically using cholesterol reagent
Baseline (week 0) to Week 8
digestive Health and General Wellness questionnaires (Rand SF-36)
Time Frame: Baseline (week 0) to Week 8
The Weekly Digestive Symptom Log measures gastrointestinal symptoms (gas, bloating, diarrhea, etc.) and will be completed daily by all subjects. The Rand SF-36 will be completed at baseline (week 0), and week 4 visits to report on patients' overall well-being
Baseline (week 0) to Week 8
urine content of syringic acid, and ellagic acid metabolites - ellagic acid, and dimethylellagic acid glucuronide
Time Frame: Baseline (week 0) to Week 8
as biomarkers for compliance
Baseline (week 0) to Week 8

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 California, Los Angeles

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.
The 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.
October 5, 2020

Primary Completion (Actual)

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.
March 6, 2021

Study Completion (Actual)

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.
July 30, 2021

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).
August 24, 2021

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.
August 24, 2021

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.
August 27, 2021

Study Record Updates

Last Update Posted (Estimate)

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.
May 5, 2023

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.
May 4, 2023

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.
May 1, 2023

More Information

Terms related to this study

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.
  • 18-001635

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

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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