Green tea inhibits adipogenesis
Inhibition of adipogenesis by green tea and green tea extract has been demonstrated in cell lines, animal models, and humans. The obesity-preventive effects of green tea and its main constituent Epigallocatechin gallate are widely supported by results from epidemiological, cell culture, animal, and clinical studies. Studies with adipocyte cell lines and animal models have demonstrated that EGCG inhibits extracellular signal-related kinases (ERK), activates AMP-activated protein kinase (AMPK), modulates adipocyte marker proteins, and down-regulates lipogenic
enzymes as well as other potential targets.
Green tea reduces abdominal fat
A study by Maki et al. evaluated the influence of a green tea catechin beverage on body composition and fat distribution in 132 overweight and obese adults during exercise-induced weight loss. Participants were randomly assigned
to receive a beverage containing approximately 625 mg of catechins
with 39 mg caffeine or a control beverage (39 mg caffeine, no catechins) for 12 weeks. Participants
were asked to maintain constant energy intake and engage in >or= 180 min/wk moderate intensity exercise, including >or= 3
supervised sessions per week. There was a trend
(p = 0.079) toward greater loss of body weight in the catechin group compared with the control group. Percentage changes in fat mass did not differ between the catechin and control groups. However, percentage reduction in total abdominal fat area, subcutaneous abdominal fat area, and fasting serum triglycerides (TG) were greater in the catechin group. These findings suggest that green tea catechin consumption enhances exercise-induced changes in abdominal fat and serum TG.
Green tea reduces waist circumference
The effects of continuous ingestion of a catechin-rich beverage in patients with type 2 diabetes who were not receiving insulin (Ins) therapy in a double-blind controlled study was investigated by Nagao et al. The participants ingested green tea containing either 582.8 mg of catechins (catechin group; n = 23) or 96.3 mg of catechins (control group; n = 20) per day for 12 weeks. At week 12, the decrease in waist circumference was significantly greater in the catechin group than in the control group. Adiponectin, which is negatively correlated with visceral adiposity, increased significantly only in the catechin group. There was also an increase in Ins at week 12, which was significantly greater in the catechin
group treated with
at week 12 was
group than in the increase in Ins levels group. In the catechin treatments, Ins levels addition, in patients
than in the control group. In patients insulinotropic agents, the increase in Ins significantly greater in the catechin control group. This significant was observed only in the catechin group receiving other remained unchanged. In
treated with insulinotropic agents, the decrease in hemoglobin A( I c) at week 12
was significantly greater in
the catechin group than in the control group.
These results suggest that a catechin-rich beverage might have
~ several therapeutic U uses: in the
prevention of obesity; in the recovery of Insยญsecretory ability; and, as a way to maintain low hemoglobin A( I c) levels in type 2 diabetic patients who do not yet require Ins therapy.
Green tea increases energy expenditure, induces weight loss
This study was undertaken to investigate the effects of green tea on weight reduction in obese Thais. A randomized, controlled trial involving 60 obese subjects (body mass index, BMI > 25 kg/m2) was conducted. All subjects consumed a Thai diet containing 3 meals (8373.6 kJ/day) for 12 weeks. The diet contained 65% carbohydrates, 15% protein, and 15% fat. body weight, BMI, body composition, resting energy expenditure, and substrate oxidation were measured at baseline, and during weeks 4, 8, and 12 of the study. In comparing the two groups, differences in weight loss were 2.70, 5.10, and 3.3 kg during the 4th, 8th, and 12th weeks of the study, respectively. At the 8th and 12th weeks of the study, body weight loss was significantly different (p < 0.05). At the 8th week, the difference in resting energy expenditure was 183.38 kJ/day (p < 0.00 I), the difference in the respiratory quotient was 0.02 (p < 0.05), and no significant differences existed in satiety score, food intake, or physical activity. Urine YMA was significantly different in the 12th week of the study (p < 0.05). The results from this study show that green tea can reduce body weight in obese subjects by increasing energy expenditure and fat oxidation.