Browsing by Subject "Green tea"

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    Effects of green tea catechin extract on serum lipids in postmenopausal women: a randomized, placebo-controlled clinical trial
    (2015-05) Rose, April Lynn
    bold>ABSTRACT Objective: Test the efficacy of a green tea catechin extract (GTE) to improve lipid profile in postmenopausal women. Methods: 886 women were enrolled and randomized to consume either 1200 mg of GTE (800 mg EGCG) or placebo, daily. Fasting serum samples were drawn for lipid panel at baseline, midpoint (month 6), and endpoint (month 12) of study for ananlysis. Results: After one year on treatment, total cholesterol (-4.6 mg/dL, P<.0001), LDL-C (-5.0 mg/dL, P<.0001), and non-HDL cholesterol (-4.4 mg/dL, P>.0001) were significantly reduced in the GTE group. The largest reductions in TC, LDL-C, and non-HDLC occurred in participants with baseline total cholesterol >200 mg/dL. HDL-C decreased slightly in the GTE group, both after 6 months on treatment (P=.0016), and overall (P=.0038). Conclusion: Daily supplementation of GTE at 1200 mg (800 mg EGCG) for one year significantly reduced levels of TC, LDL-C, and non-HDLC in a population of postmenopausal women.
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    Effects of Green Tea Extract on Biomarkers of Breast Cancer Risk Including Reproductive Hormones and IGF axis Proteins
    (2015-08) Samavat, Hamed
    Objective: To investigate the effects of daily intake of a highly concentrated green tea extract (GTE) for one year on circulating sex hormones and insulin-like growth factor (IGF) proteins as well as urinary estrogens and estrogen metabolites in postmenopausal women with different catechol-O-methyltransferase (COMT) genotypes. Method: The Minnesota Green Tea Trial (MGTT) is a randomized, double-blind, placebo-controlled, phase II clinical trial. Healthy postmenopausal women with heterogeneously or extremely dense breast tissue (age = 59.78 ± 5.02 years; body mass index= 25.70 ± 8.21 kg/m2) were randomly assigned to the GTE group (n=538) and were given 4 capsules a day, each containing 200 mg epigallocatechin gallate (EGCG) and the others (n=537) to the placebo group. Participants were 93% non-Hispanic white and non-current hormone users. Twenty-four hour urine samples were collected at month 0 and at the end of the study, and fasting blood samples were drawn at months 0, 6 and 12. Circulating and urinary estrogens, as well as urinary estrogen metabolites were quantified by the liquid chromatography-tandem mass spectrometry method. Blood IGF axis proteins were analyzed by ELISA. Results: GTE supplementation was associated with reduced urinary estriol levels (P= 0.02) and higher urinary 2-hydroxyestrone (P= 0.02) compared to the placebo. There was also less of a reduction in the urinary levels of 16α-hydroxyestrone in the GTE versus placebo group. Intake of the GTE resulted in significant increase of circulating estradiol and testosterone and their corresponding free and bioavailable fractions, whereas these measures were reduced in the placebo group. Additionally, COMT genotype did not modify the GTE effect on either circulating sex hormones and IGF proteins or urinary estrogens. Conclusion: Daily intake of high-dose of green tea extract for 12 month exerts modest effects on urinary excretion of estrogen metabolites, yet these effects are not modified by the COMT polymorphisms. Potential breast cancer protective effects of GTE are not mediated by alterations in circulating sex hormones or IGF axis proteins.