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

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.

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.