A randomized, double-blind, placebo-controlled phase II trial to examine the effect of Polyphenon E on endogenous hormone levels

Unrestricted In this randomized, double-blind, placebo-controlled phase II trial to examine the effect of Polyphenon E [containing the most important polyphenol, epidgallocatechin gallate (EGCG) in green tea] on endogenous hormone profiles, 111 participants were recruited and randomized into three different experimental arms: 400 mg EGCG daily, 800 mg EGCG daily or placebo for a period of 60 days. Four steroid hormones: androstenedione (Andr), testosterone (T), estrone (E1) and estradiol (E2), and two protein hormones: adiponectin (Adip) and insulin-like growth factor 1 (IGF1), plus two hormone binding proteins: IGF binding protein 3 (IGFbp3) and sex hormone binding globulin (SHBG) levels were measured at baseline, at end of month-1 and at end of month-2. This study failed to provide confirmatory evidence of lower serum E1 and E2 values due to green tea consumption. The E1 and E2 values declined in the group treated with EGCG but similar declines were also seen in the placebo group. The only treatment effect suggesting a protective effect against breast cancer was a decline in IGFbp3.