The safety of green tea extract supplementation in postmenopausal women at risk for breast cancer: Results of the Minnesota green tea trial
Allison M Dostal
University of Minnesota, USA
: Forensic Toxicol Pharmacol 2015, 4:3
Abstract
Green tea is a popular beverage and is thought to provide health benefits, though adverse reactions to green tea extract (GTE) have been reported and are not well understood. We conducted a randomized, double-blind, placebo-controlled study of GTE in which 1075 postmenopausal women with high mammographic density were randomly assigned to consume GTE containing 843 mg (-)-epigallocatechin-3-gallate (EGCG) or placebo daily for one year. There were no significant differences in % of women with AEs (75.6% and 72.8% of GTE and placebo groups respectively) or serious AEs (2.2 % and 1.5% of GTE and placebo group respectively). Women on GTE reported significantly higher incidence of nausea (P<0.001) and dermatologic AEs (P=0.05) and significantly lower diarrhea incidence (P=0.02). More women in the GTE group experienced an alanine aminotransferase (ALT) elevation compared with placebo group (n=36 (6.7%) vs. n=4, (0.7%); P<0.001). There were no statistically significant differences between groups in frequencies of other AEs. Overall, AEs were mainly mild and transient indicating that daily consumption of GTE containing 843 mg EGCG is generally well tolerated by a group of predominantly Caucasian postmenopausal women. However, 6.7% of GTE consumers experienced ALT elevations with 1.3% experiencing ALT-related serious AEs.