Gut-level Antiinflammatory Activities of Green Tea in Metabolic Syndrome

NCT ID: NCT03973996

Last Updated: 2025-12-19

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 46 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2019-07-01
• Study Completion Date: 2021-03-01

Brief Summary

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.

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.

Conditions

Dysbiosis; Endotoxemia; Metabolic Syndrome; Inflammation

Keywords

Green tea; Gut barrier function; Gut dysbiosis; Inflammation; Metabolic endotoxemia; Metabolic syndrome; Microbiome

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: CROSSOVER
• Primary Study Purpose: PREVENTION
• Blinding Strategy: DOUBLE

Study Groups

Green Tea

Participants consuming gummy confections with catechin-rich green tea extract daily for 4 weeks

Group Type: EXPERIMENTAL

Green Tea Extract

Intervention Type: DIETARY_SUPPLEMENT

A gummy confection with catechin-rich green tea extract (1 g/d)

Placebo

Participants consuming matched gummy confections formulated without green tea extract daily for 4 weeks

Group Type: PLACEBO_COMPARATOR

Placebo

Intervention Type: DIETARY_SUPPLEMENT

A matched gummy confection formulated without green tea extract

Interventions

Green Tea Extract

A gummy confection with catechin-rich green tea extract (1 g/d)

Intervention Type: DIETARY_SUPPLEMENT

Placebo

A matched gummy confection formulated without green tea extract

Intervention Type: DIETARY_SUPPLEMENT

Other Intervention Names

Camellia sinesis plant extract

Eligibility Criteria

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

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 65 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

United States Department of Agriculture (USDA)

FED

Sponsor Role: collaborator

Ohio State University

OTHER

Sponsor Role: lead

Responsible Party

Richard Bruno

Principal Investigator

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Richard S Bruno, PhD, RD

Role: PRINCIPAL_INVESTIGATOR

Ohio State University

Locations

The Ohio State University

Columbus, Ohio, United States

Countries

United States

References

Dey P, Sasaki GY, Wei P, Li J, Wang L, Zhu J, McTigue D, Yu Z, Bruno RS. Green tea extract prevents obesity in male mice by alleviating gut dysbiosis in association with improved intestinal barrier function that limits endotoxin translocation and adipose inflammation. J Nutr Biochem. 2019 May;67:78-89. doi: 10.1016/j.jnutbio.2019.01.017. Epub 2019 Feb 8.

Reference Type: BACKGROUND

PMID: 30856467 (View on PubMed)

Li J, Sasaki GY, Dey P, Chitchumroonchokchai C, Labyk AN, McDonald JD, Kim JB, Bruno RS. Green tea extract protects against hepatic NFkappaB activation along the gut-liver axis in diet-induced obese mice with nonalcoholic steatohepatitis by reducing endotoxin and TLR4/MyD88 signaling. J Nutr Biochem. 2018 Mar;53:58-65. doi: 10.1016/j.jnutbio.2017.10.016. Epub 2017 Nov 3.

Reference Type: BACKGROUND

PMID: 29190550 (View on PubMed)

Hodges JK, Zhu J, Yu Z, Vodovotz Y, Brock G, Sasaki GY, Dey P, Bruno RS. Intestinal-level anti-inflammatory bioactivities of catechin-rich green tea: Rationale, design, and methods of a double-blind, randomized, placebo-controlled crossover trial in metabolic syndrome and healthy adults. Contemp Clin Trials Commun. 2019 Nov 20;17:100495. doi: 10.1016/j.conctc.2019.100495. eCollection 2020 Mar.

Reference Type: BACKGROUND

PMID: 31799477 (View on PubMed)

Zeng M, Hodges JK, Pokala A, Khalafi M, Sasaki GY, Pierson J, Cao S, Brock G, Yu Z, Zhu J, Vodovotz Y, Bruno RS. A green tea extract confection decreases circulating endotoxin and fasting glucose by improving gut barrier function but without affecting systemic inflammation: A double-blind, placebo-controlled randomized trial in healthy adults and adults with metabolic syndrome. Nutr Res. 2024 Apr;124:94-110. doi: 10.1016/j.nutres.2024.02.001. Epub 2024 Feb 5.

Reference Type: RESULT

PMID: 38430822 (View on PubMed)

Provided Documents

Document Type: Study Protocol and Statistical Analysis Plan

View Document

Other Identifiers

2018H0592

Identifier Type: -

Identifier Source: org_study_id