Trial reportThe Journal of nutrition2019
Green Tea Catechin Extract Supplementation Does Not Influence Circulating Sex Hormones and Insulin-Like Growth Factor Axis Proteins in a Randomized Controlled Trial of Postmenopausal Women at High Risk of Breast Cancer.
Trial report in The Journal of nutrition, 2019. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to trial NCT00917735 (Phase II, Randomized,Double-blind, Placebo-controlled, Study of the Efficacy of Green Tea Extract on Biomarkers of Breast Cancer Risk in High Risk Women With Differing Catechol-O-methyl Transferase), which is not on this map. Cited by 13 papers, 1 of them a synthesis that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Phase II, Randomized,Double-blind, Placebo-controlled, Study of the Efficacy of Green Tea Extract on Biomarkers of Breast Cancer Risk in High Risk Women With Differing Catechol-O-methyl Transferase (COMT) Genotypes
Who cites it
13 citing papers in PubMed, 1 synthesis or guideline pooled it, 33 citations in OpenAlex.
- The Effects of Diet and Exercise on Endogenous Estrogens and Subsequent Breast Cancer Risk in Postmenopausal Women.Frontiers in endocrinology · 2021Pooled it
- Anticancer Molecular Mechanisms of Epigallocatechin Gallate: An Updated Review on Clinical Trials.Food science & nutrition · 2025Review
- Synergistic strength: unleashing exercise and polyphenols against breast cancer.Cancer cell international · 2025Review
- Green tea, other teas and coffee consumption and risk of death from chronic kidney disease as the underlying cause among Japanese men and women: the JACC Study.Environmental health and preventive medicine · 2025Article
- Assessment of Integrative Therapeutic Methods for Improving the Quality of Life and Functioning in Cancer Patients-A Systematic Review.Journal of clinical medicine · 2024Review
- Nutritional aphrodisiacs: Biochemistry and Pharmacology.Current research in food science · 2024Review
- Current Understanding of Flavonoids in Cancer Therapy and Prevention.Metabolites · 2023Review
- The potential of epigallocatechin gallate in the chemoprevention and therapy of hepatocellular carcinoma.Frontiers in pharmacology · 2023Review
- Review
- Green Tea Epigallocatechin-3-Gallate Regulates Autophagy in Male and Female Reproductive Cancer.Frontiers in pharmacology · 2022Review
- Impact of Stilbenes as Epigenetic Modulators of Breast Cancer Risk and Associated Biomarkers.International journal of molecular sciences · 2021Review
- The Hallmarks of Flavonoids in Cancer.Molecules (Basel, Switzerland) · 2021Review
- Antioxidants for the Treatment of Breast Cancer: Are We There Yet?Antioxidants (Basel, Switzerland) · 2021Review
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
9 authors at 4 institutions in 2 countries.
Funding
Abstract
backgroundConsumption of green tea has been associated with reduced risk of breast cancer. Hormonal modulation has been suggested as one of the potential underlying mechanisms; however, it has yet to be fully elucidated in large, long-term human clinical trials.
objectiveWe investigated the effects of decaffeinated green tea extract (GTE) on circulating sex hormones and insulin-like growth factor (IGF) proteins.
methodsWe conducted a placebo-controlled double-blind randomized clinical trial recruiting from 8 clinical centers in Minnesota. Participants were 538 healthy postmenopausal women randomly assigned to the GTE group (463 completed the study; mean age = 60.0 y) and 537 to the placebo group (474 completed; mean age = 59.7 y). Women in the GTE group orally took 4 decaffeinated capsules containing 1315 mg total catechins including 843 mg epigallocatechin-3-gallate daily for 1 y, whereas women in the placebo group took similar capsules containing no tea catechins. Blood sex hormones (estrone, estradiol, androstenedione, testosterone, and sex hormone-binding globulin) and IGF proteins (IGF-1 and IGF binding protein-3) were quantified at baseline and months 6 (for IGF proteins only) and 12, and were assessed as secondary outcomes of the study using a mixed-effect repeated-measures ANOVA model.
resultsWomen in the GTE group had significantly higher blood total estradiol (16%; P = 0.02) and bioavailable estradiol (21%; P = 0.03) than in the placebo group at month 12. There was a statistically significant interaction between GTE supplementation and duration of treatment on estradiol and bioavailable estradiol (both Ps for interaction = 0.001). The catechol-O-methyltransferase genotype did not influence blood sex hormones before or after GTE supplementation. The circulating concentrations of IGF proteins were comparable between GTE and placebo groups at all 3 time points.
conclusionThese results suggest that a 12-mo GTE supplementation significantly increases circulating estradiol concentrations in healthy postmenopausal women. This trial was registered at clinicaltrials.gov as NCT00917735.
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What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.