title: The safety of green tea extract supplementation in postmenopausal women at risk for breast cancer: results of the Minnesota Green Tea Trial.
abstract: Green tea is thought to provide health benefits, though adverse reactions to green tea extract (GTE) have been reported. We conducted a randomized, double-blind, placebo-controlled study of GTE on breast cancer biomarkers, including mammographic density, in which 1075 postmenopausal women 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 adverse events (AEs, 75.6% and 72.8% of the GTE group and placebo group, respectively) or serious AEs (2.2 % and 1.5% of GTE and placebo groups, 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.
authors.affiliation: Department of Food Science and Nutrition, University of Minnesota, 1334 Eckles Ave., St. Paul, MN 55108, USA. Electronic address: dost0022@umn.edu.
authors.forename: Allison M
authors.initials: AM
authors.lastname: Dostal
authors.affiliation: Department of Food Science and Nutrition, University of Minnesota, 1334 Eckles Ave., St. Paul, MN 55108, USA. Electronic address: samav005@umn.edu.
authors.forename: Hamed
authors.initials: H
authors.lastname: Samavat
authors.affiliation: Department of Food Science and Nutrition, University of Minnesota, 1334 Eckles Ave., St. Paul, MN 55108, USA. Electronic address: sbedell@umn.edu.
authors.forename: Sarah
authors.initials: S
authors.lastname: Bedell
authors.affiliation: Department of Family Medicine, University of Minnesota Medical Center, 420 Delaware St. SE, Minneapolis, MN 55455, USA. Electronic address: tork0004@umn.edu.
authors.forename: Carolyn
authors.initials: C
authors.lastname: Torkelson
authors.affiliation: University of Pittsburgh Cancer Institute, Division of Cancer Control and Population Sciences, University of Pittsburgh Graduate School of Public Health, Department of Epidemiology, 5150 Centre Ave., Pittsburgh, PA 15232, USA. Electronic address: wangr2@upmc.edu.
authors.forename: Renwei
authors.initials: R
authors.lastname: Wang
authors.affiliation: Virginia Piper Cancer Institute, Allina Health System, 800 East 28th St., Suite 602, Minneapolis, MN 55407, USA. Electronic address: karen.swenson2@allina.com.
authors.forename: Karen
authors.initials: K
authors.lastname: Swenson
authors.affiliation: Biostatistics and Informatics Core, Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA. Electronic address: chap@umn.edu.
authors.forename: Chap
authors.initials: C
authors.lastname: Le
authors.affiliation: Department of Preventive Medicine, University of Southern California Keck School of Medicine, 1975 Zonal Ave., Los Angeles, CA 90033, USA. Electronic address: anna.wu@med.usc.edu.
authors.forename: Anna H
authors.initials: AH
authors.lastname: Wu
authors.affiliation: Department of Preventive Medicine, University of Southern California Keck School of Medicine, 1975 Zonal Ave., Los Angeles, CA 90033, USA; Cancer Registry of Norway, Oslo, Norway; Department of Nutrition, University of Oslo, Oslo, Norway. Electronic address: Giske.Ursin@kreftregisteret.no.
authors.forename: Giske
authors.initials: G
authors.lastname: Ursin
authors.affiliation: University of Pittsburgh Cancer Institute, Division of Cancer Control and Population Sciences, University of Pittsburgh Graduate School of Public Health, Department of Epidemiology, 5150 Centre Ave., Pittsburgh, PA 15232, USA. Electronic address: yuanj@upmc.edu.
authors.forename: Jian-Min
authors.initials: JM
authors.lastname: Yuan
authors.affiliation: Department of Food Science and Nutrition, University of Minnesota, 1334 Eckles Ave., St. Paul, MN 55108, USA. Electronic address: mkurzer@umn.edu.
authors.forename: Mindy S
authors.initials: MS
authors.lastname: Kurzer
mesh_terms: D000368:Aged; D016588:Anticarcinogenic Agents / Q000009:adverse effects* / Q000627:therapeutic use; D000975:Antioxidants / Q000009:adverse effects* / Q000737:chemistry / Q000627:therapeutic use; D015415:Biomarkers / Q000097:blood; D000071060:Breast Density; D001943:Breast Neoplasms / Q000097:blood / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000517:prevention & control*; D028241:Camellia sinensis / Q000737:chemistry*; D002392:Catechin / Q000009:adverse effects / Q000031:analogs & derivatives / Q000032:analysis / Q000627:therapeutic use; D019587:Dietary Supplements / Q000009:adverse effects* / Q000032:analysis; D004311:Double-Blind Method; D005260:Female; D005511:Food Handling; D048550:Hepatic Insufficiency / Q000209:etiology / Q000503:physiopathology; D006801:Humans; D042361:Mammary Glands, Human / Q000002:abnormalities; D008875:Middle Aged; D008910:Minnesota / Q000453:epidemiology; D010936:Plant Extracts / Q000009:adverse effects* / Q000737:chemistry / Q000627:therapeutic use; D018515:Plant Leaves / Q000737:chemistry*; D011859:Radiography; D012307:Risk Factors; D012720:Severity of Illness Index
chemical_list: D016588:Anticarcinogenic Agents; D000975:Antioxidants; D015415:Biomarkers; D010936:Plant Extracts; D002392:Catechin; C045651:epigallocatechin gallate
keywords: Adverse events; Breast cancer; EGCG; Green tea; Hepatotoxicity; Postmenopausal