Scientists in Taiwan studied the effect of green tea extract on 78 obese women aged 16 to 60 years. They found no significant improvement in body weight, body mass index and weight circumflex. There were significant improvements in LDL cholesterol and triglyceride.
Effect of green tea extract on obese women: A randomized, double-blind, placebo-controlled clinical trial.
Clin Nutr. 2008 May 9. [Epub ahead of print]. Hsu CH, Tsai TH, Kao YH, Hwang KC, Tseng TY, Chou P.
AIMS: To examine the effect of green tea extract (GTE) on obese women and to explore the relationship between GTE and obesity-related hormone peptides. METHODS: A randomized, double-blind, placebo-controlled clinical trial was conducted from July 2006 to June 2007 in Taipei Hospital, Taiwan. Seventy-eight of 100 obese women aged between 16 and 60years with BMI>27kg/m(2) and who had not received any other weight control maneuvers within the last 3months completed this study. The subjects were randomly divided into Groups A and B. Group A (n=41) received GTE while Group B (n=37) took cellulose as a placebo, one capsule (400mg) three times each day for 12weeks. The body weight (BW), body mass index (BMI) and waist circumflex (WC) were measured at the beginning of the study and after 12weeks of treatment with GTE. The data were compared and expressed as % reduction. RESULTS: There was only a 0.3% reduction in BW (0.15kg) after 12weeks of treatment with GTE. There was no statistical difference in % reduction in BW, BMI and WC between the GTE and placebo groups. Within group comparison revealed that the GTE group had significant reduction in LDL-cholesterol and triglyceride, and marked increase in the level of HDL-cholesterol, adiponectin and ghrelin. On the other hand, the placebo group showed significant reduction in triglyceride only, and a marked increase in the level of ghrelin alone. CONCLUSIONS: This study showed no statistical difference in % reduction in BW, BMI and WC between the GTE and placebo groups after 12weeks of treatment. The intake of GTE (491mg catechins containing 302mg EGCG) for 12weeks is considered safe as shown by the results.