- 1Department of Food Science and Nutrition, University of Minnesota, St. Paul, MN.
- 2Division of Cancer Control and Population Sciences, University of Pittsburgh Cancer Institute, Pittsburgh, PA.
- 3Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA; and.
- 4Department of Preventive Medicine, University of Southern California Keck School of Medicine, Los Angeles, CA.
- 5Department of Food Science and Nutrition, University of Minnesota, St. Paul, MN; mkurzer@umn.edu.
Abstract
BACKGROUND:
Green tea
has been suggested to improve cardiovascular disease risk factors,
including circulating lipid variables. However, current evidence is
predominantly based on small, short-term randomized controlled trials
conducted in diverse populations.
OBJECTIVE:
The aim of this study was to examine the efficacy and impact of green tea extract (GTE) supplementation high in epigallocatechin gallate (EGCG) on blood lipids in healthy postmenopausal women.
DESIGN:
This
was an ancillary study of a double-blind, randomized,
placebo-controlled, parallel-arm trial investigating the effects of a
GTE supplement containing 1315 mg catechins (843 mg EGCG) on biomarkers
of breast cancer risk. Participants were randomly assigned to receive
GTE (n = 538) or placebo (n = 537) and were stratified by
catechol-O-methyltransferase (COMT) genotype activity (high COMT
compared with low or intermediate COMT genotype activity). They consumed
either 4 GTE or identical placebo capsules daily for 12 mo. A total of
936 women completed this substudy. Circulating lipid panels including
total cholesterol (TC), HDL cholesterol, and triglycerides were measured at baseline and at months 6 and 12.
RESULTS:
Compared
with placebo, 1-y supplementation with GTE capsules resulted in a
significant reduction in circulating TC (-2.1% compared with 0.7%; P =
0.0004), LDL cholesterol (-4.1% compared with 0.9%; P < 0.0001) and non-HDL cholesterol (-3.1% compared with 0.4%; P = 0.0032). There was no change in HDL-cholesterol
concentration, but triglyceride concentrations increased by 3.6% in the
GTE group, whereas they decreased by 2.5% in the placebo group (P =
0.046). A significant reduction in TC was observed only among women with
high (i.e., ≥200 mg/dL) baseline TC concentrations (P-interaction =
0.01) who consumed GTE capsules. The effect of GTE on the increase in
triglycerides was mainly observed among obese women and statin users
(P-interaction = 0.06).
CONCLUSION:
Supplementation with GTE significantly reduced circulating TC and LDL-
cholesterol
concentrations, especially in those with elevated baseline TC
concentrations. This trial was registered at clinicaltrials.gov as
NCT00917735.
© 2016 American Society for Nutrition.
KEYWORDS:
EGCG; blood lipids; cardiovascular; green tea; postmenopausal; randomized controlled trial
