Gut-level Antiinflammatory Activities of Green Tea in Metabolic Syndrome

December 3, 2025 updated by: Richard Bruno, Ohio State University
This study evaluates dietary green tea extract to improve gut health and inflammation in persons with metabolic syndrome and healthy adults. Participants will complete two phases of intervention in random order in which they will consume green tea extract or placebo for one month and then switch to the opposite treatment for an additional month.

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

Tea is the most abundantly consumed prepared beverage in the world. Green tea, containing catechins, exerts antiinflammatory activities. However, a fundamental gap exists concerning its intestinal-level targets that can prevent metabolic syndrome (MetS) development and progression. Studies in obese rodents indicate that green tea inhibits nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB) activation by limiting gut-derived endotoxin translocation to the portal circulation and decreasing hepatic Toll-like receptor-4 (TLR4) pro-inflammatory signaling. The objective of this clinical investigation is to establish evidence-based recommendations for green tea, based on improvements in endotoxemia and restored gut barrier function, that promote optimal health. The hypothesis is that green tea catechins function to limit metabolic endotoxemia by ameliorating gut dysbiosis-mediated inflammation that otherwise provokes intestinal permeability. This will be tested by conducting a double-blind, placebo-controlled, randomized-order, crossover trial in MetS and healthy persons to examine the efficacy of green tea on metabolic endotoxemia. Each treatment will be one-month in duration and separated by a washout period. The anticipated outcomes are expected to be of significance, because they will advance a dietary strategy to help avert MetS complications attributed to metabolic endotoxemia by establishing antiinflammatory prebiotic and antimicrobial bioactivities of catechins that promote intestinal health.

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.
46

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
    • Ohio
      • Columbus, Ohio, United States, 43210
        • The Ohio State University

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 65 years (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Description

Inclusion criteria:

Individuals with ≥3 of the following established criteria for metabolic syndrome:

  • Fasting glucose 100-126 mg/dL
  • Waist circumference >89/>102 cm for females/males
  • HDL-C <50/<40 mg/dL for females/males
  • Triglyceride >150 mg/dL
  • Blood pressure >130/85 mmHg

Healthy adults:

  • Body weight 19-25 kg/m2
  • Fasting glucose <100 mg/dL
  • HDL-C >50/>40 mg/dL for females/males
  • Triglyceride <150 mg/dL
  • Blood pressure <120/80 mmHg

Exclusion criteria:

  • Concurrent tea consumption
  • Use of dietary supplements, prebiotics, or probiotics
  • Use of antibiotics or antiinflammatory agents
  • History of liver disease, cardiovascular disease, hypertension (blood pressure >140/90 mmHg), or cancer
  • History of gastrointestinal disorders, chronic diarrhea, or surgeries
  • Hemochromatosis
  • Parkinson's disease
  • Use of medications to manage diabetes, hypertension, or hyperlipidemia
  • Use of antipsychotic medications [Clozapine, lithium, Diazepam]
  • Use of blood thinning medications [Warfarin]
  • Use of high blood pressure medications [nadolol]
  • Use of monoamine oxidase inhibitors [selegiline]
  • Alcohol consumption >2 drinks/d
  • Smoking tobacco
  • Vegetarian
  • Pregnancy, lactation, or recent changes in birth control use for women

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: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Double

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: Green Tea
Participants consuming gummy confections with catechin-rich green tea extract daily for 4 weeks
Dietary supplement: Green Tea Extract
A gummy confection with catechin-rich green tea extract (1 g/d)
Other Names:
  • Camellia sinesis plant extract
Placebo Comparator: Placebo
Participants consuming matched gummy confections formulated without green tea extract daily for 4 weeks
Dietary supplement: Placebo
A matched gummy confection formulated without green tea extract

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
Serum Endotoxin
Time Frame: Day 28
Data are biomarker fasting concentrations.
Day 28

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
Plasma Lipopolysaccharide-binding Protein
Time Frame: Day 28
Data are biomarker fasting concentrations
Day 28
Urinary Lactulose/Mannitol Ratio
Time Frame: Day 28
Lactulose/mannitol ratio in urine collected 0-5 h post-ingestion of non-digestible sugar probes.
Day 28
Urinary Sucralose/Erythritol Ratio
Time Frame: Day 28
Sucralose/Erythritol ratio measured in urine collected 0-24 h post-ingestion of non-digestible sugar probes
Day 28
Plasma Interleukin-6
Time Frame: Day 28
Data are biomarker concentrations at fasting
Day 28
Fecal Calprotectin
Time Frame: Day 25-27 (pooled samples) of the 28-day intervention
Data are biomarker fecal concentrations, measured in samples pooled from specimens collected on Days 25-27 of the 28-day intervention.
Day 25-27 (pooled samples) of the 28-day intervention
Fecal Myeloperoxidase
Time Frame: Day 25-27 (pooled samples) of the 28-day intervention
Data are biomarker fecal concentrations, measured in samples pooled from specimens collected on Days 25-27 of the 28-day intervention.
Day 25-27 (pooled samples) of the 28-day intervention
Plasma Epigallocatechin Gallate
Time Frame: Day 28
Data are plasma concentrations of epigallocatechin gallate
Day 28
Plasma Epicatechin
Time Frame: Day 28
Data are plasma concentrations of epicatechin.
Day 28
Plasma Epicatechin Gallate
Time Frame: Day 28
Data are plasma concentrations of epicatechin gallate.
Day 28
Plasma 3,4-γ-valerolactone
Time Frame: Day 28
Data are biomarker concentrations at fasting
Day 28
Plasma 3,4,5-γ-Valerolactone
Time Frame: Day 28
Data are biomarker concentrations at fasting
Day 28
Plasma Soluble Cluster of Differentiation-14
Time Frame: Day 28
Data are biomarker concentrations at fasting
Day 28
Plasma Glucose
Time Frame: Day 28
Data are biomarker concentrations at fasting
Day 28
Plasma Insulin
Time Frame: Day 28
Data are biomarker concentrations at fasting
Day 28
Plasma Triglyceride
Time Frame: Day 28
Data are biomarker concentrations at fasting
Day 28
Plasma Total Cholesterol
Time Frame: Day 28
Data are biomarker concentrations at fasting
Day 28
Serum Alanine Transaminase
Time Frame: Day 28
Data are biomarker concentrations at fasting
Day 28
Serum Aspartate Transaminase
Time Frame: Day 28
Data are biomarker concentrations at fasting
Day 28
Blood Hematocrit
Time Frame: Day 28
Data are biomarker concentrations at fasting
Day 28
Plasma Tumor Necrosis Factor-alpha
Time Frame: Day 28
Data are biomarker fasting concentrations
Day 28
Fecal Butyrate
Time Frame: Days 25-27 (pooled samples) of the 28-day intervention
Data are biomarker concentrations in fecal samples, measured in samples pooled from specimens collected on Days 25-27 of the 28-day intervention.
Days 25-27 (pooled samples) of the 28-day intervention
Fecal Acetate
Time Frame: Days 25-27 (pooled samples) of the 28-day intervention
Data are biomarker concentrations in fecal samples, measured in samples pooled from specimens collected on Days 25-27 of the 28-day intervention.
Days 25-27 (pooled samples) of the 28-day intervention
Fecal Valeric Acid
Time Frame: Day 25-27 (pooled samples) from the 28-day intervention
Data are biomarker concentrations in fecal samples, measured in samples pooled from specimens collected on Days 25-27 of the 28-day intervention.
Day 25-27 (pooled samples) from the 28-day intervention
Fecal Hexanoic Acid
Time Frame: Day 25-27 (pooled samples) from the 28-day intervention
Data are biomarker concentrations in fecal samples, measured in samples pooled from specimens collected on Days 25-27 of the 28-day intervention.
Day 25-27 (pooled samples) from the 28-day intervention
Fecal Isobutyric Acid
Time Frame: Day 25-27 (pooled samples) from the 28-day intervention
Data are biomarker concentrations in fecal samples, measured in samples pooled from specimens collected on Days 25-27 of the 28-day intervention.
Day 25-27 (pooled samples) from the 28-day intervention
Fecal 2-Methylbutyric
Time Frame: Day 25-27 (pooled samples) of the 28-day intervention
Data are biomarker concentrations in fecal samples, measured in samples pooled from specimens collected on Days 25-27 of the 28-day intervention.
Day 25-27 (pooled samples) of the 28-day intervention
Fecal Isovaleric Acid
Time Frame: Day 25-27 (pooled samples) of the 28-day intervention
Data are biomarker concentrations in fecal samples, measured in samples pooled from specimens collected on Days 25-27 of the 28-day intervention.
Day 25-27 (pooled samples) of the 28-day intervention
Plasma Ascorbic Acid
Time Frame: Day 28
Data are biomarker fasting concentrations
Day 28
Plasma Uric Acid
Time Frame: Day 28
Data are biomarker fasting concentrations
Day 28

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.
Ohio State University

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.
United States Department of Agriculture (USDA)

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Richard S Bruno, PhD, RD, Ohio State University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

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.
July 1, 2019

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 1, 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.
March 1, 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).
May 30, 2019

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.
June 3, 2019

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.
June 4, 2019

Study Record Updates

Last Update Posted (Estimated)

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.
December 19, 2025

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.
December 3, 2025

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.
December 1, 2025

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.
  • 2018H0592

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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