Long-term Effects of Green Tea on Gut Flora, Fat Absorption, Body Composition and Resting Energy Expenditure

Study Overview
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Brief Summary
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Green tea may have positive effects for weight control and on body composition via several approaches such as a positive effect on the gut flora, a decrease in fat absorption from the intestines and an increase in resting energy expenditure.

Detailed Description
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Green tea may have positive effects for weight control and on body composition via several approaches such as a positive effect on the gut flora, a decrease in fat absorption from the intestines and an increase in resting energy expenditure. We would like to investigate the long-term effects of green tea on gut flora, fat absorption, resting energy expenditure and body composition. The study will be conducted in a randomized, placebo-controlled, double-blind parallel design with four groups consisting of control groups and green tea groups with normal weight subjects and obese subjects. At three time points (baseline, 6 weeks and 12 weeks) faeces are collected for analyzing the gut flora composition and fat content. Furthermore, measurements of resting energy expenditure and body composition will be conducted. Activity will be measured during three weeks (baseline, week 6 and week 12). a hundred healthy subjects (50 males and 50 females) with a BMI between 18.5-25 kg/m2 and ≥30 kg/m2 and aged between 18-50 years will be included in the study. All subjects will be non-smoking, non tea-drinkers, weight stable, dietary unrestraint, and at most moderate alcohol and caffeine consumers. Subjects will be free of medication except for oral contraceptives use in women. Intervention (if applicable): Subjects will receive either green tea or placebo in capsule form after their baseline measurement, which they have to consume three times daily for a period of twelve weeks.

Official Title
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Long-term Effects of Green Tea on Gut Flora, Fat Absorption, Body Composition and Resting Energy Expenditure

Conditions
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Obesity

Intervention / Treatment
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* Dietary Supplement: placebo
* Dietary Supplement: green tea (757 mg/capsule [84.5 mg EGCG + 2.1 mg caffeine ]


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: BMI between 18.5-25 kg/m2 and ≥30 kg/m2 Age between 18-50 years Healthy Weight stable Dietary unrestraint Not using a more than moderate amount of alcohol (>10 consumptions/wk) Not using more than 100 mg caffeine per day Not drinking tea Not using probiotics Being weight stable (weight change < 3kg during the last 6 months) Dietary unrestraint Not using antibiotics during the last 6 months. Free of medication except for oral contraceptives use in women. Exclusion Criteria: Not healthy Smoking Using a more than moderate amount of alcohol Using more than 100 mg caffeine per day Drinking tea Using probiotics Not being weight stable Dietary restraint Using medication or supplements except for oral contraceptives in women Using antibiotics Not meeting the criteria for BMI and age. Pregnant or lactating women Having allergies for the used food items will also be excluded from participation.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 50 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

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


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Green tea, normal weight<br>Subjects with a BMI 18.5-25 kg/m2 will receive green tea capsules, which they have to consume daily for a period of twelve weeks | Dietary Supplement: green tea (757 mg/capsule [84.5 mg EGCG + 2.1 mg caffeine ]<br>* Subjects will receive green tea (757 mg/capsule [84.5 mg EGCG + 2.1 mg caffeine ], 3 capsules with each breakfast, lunch and dinner)in capsule form after their baseline measurement, which they have to consume daily for a period of twelve weeks.<br>|
| Placebo Comparator: Placebo, normal weight<br>Subjects with a BMI 18.5-25 kg/m2 will receive placebo capsules, which they have to consume daily for a period of twelve weeks | Dietary Supplement: placebo<br>* Subjects will receive placebo (soy oil; 757 mg/capsule, 3 capsules with each breakfast, lunch and dinner) in capsule form after their baseline measurement, which they have to consume daily for a period of twelve weeks.<br>|
| Experimental: Green tea, overweight<br>Subjects with a BMI >30 kg/m2 will receive green tea capsules, which they have to consume daily for a period of twelve weeks | Dietary Supplement: green tea (757 mg/capsule [84.5 mg EGCG + 2.1 mg caffeine ]<br>* Subjects will receive green tea (757 mg/capsule [84.5 mg EGCG + 2.1 mg caffeine ], 3 capsules with each breakfast, lunch and dinner)in capsule form after their baseline measurement, which they have to consume daily for a period of twelve weeks.<br>|
| Placebo Comparator: Placebo capsules, obese<br>Subjects with a BMI >30 kg/m2 will receive placebo capsules, which they have to consume daily for a period of twelve weeks | Dietary Supplement: placebo<br>* Subjects will receive placebo (soy oil; 757 mg/capsule, 3 capsules with each breakfast, lunch and dinner) in capsule form after their baseline measurement, which they have to consume daily for a period of twelve weeks.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Faeces are collected for analyzing the gut flora and fat absorption | The primary endpoint of this study is the change in gut flora; ratio firmicutes/bacteroidetes, changes in total faecal fat and change in body weight. | At three time points (baseline, 6 weeks and 12 weeks) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Resting energy expenditure (REE) |  | At three time points (baseline, 6 weeks and 12 weeks) | 
| Respiratory quotient (RQ) |  | At three time points (baseline, 6 weeks and 12 weeks) | 
| Three frequency eating questionnaire (TFEQ) |  | At three time points (baseline, 6 weeks and 12 weeks) | 
| Body composition: BMI, body fat percentage, fat mass index (FMI) |  | At three time points (baseline, 6 weeks and 12 weeks) | 
| Body fat distribution: waist circumference, waist-to-hip ratio (WHR |  | At three time points (baseline, 6 weeks and 12 weeks) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Obesity, Body weight, Gut flora, Fat absorption