Green Tea & Estrogen Levels
Estrogen is a hormone that is essential for the normal sexual and reproductive development of women. It is produced by the ovaries and regulates the menstrual cycle. Low estrogen levels commonly occur during menopause and may lead to symptoms such as hot flashes, night sweats, vaginal dryness and mood swings. They may also indicate other conditions including atherosclerosis and osteoporosis. High levels of the hormone may increase the risk of serious conditions including breast cancer. Medications and supplements such as green tea may help regulate estrogen levels.
If you are experiencing serious medical symptoms, seek emergency treatment immediately.
Green Tea
Green tea is made from the unfermented leaves of the Camellia sinensis plant that is native to East Asia. It is a popular beverage in many parts of the world. The supplements are available as teas, liquid extracts and capsules. If you plan to use green tea for medicinal purpose, your doctor may help determine the appropriate dose for you based on your age and health history.
- Green tea is made from the unfermented leaves of the Camellia sinensis plant that is native to East Asia.
Estrogen Levels
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The blood estrogen levels were 13 percent lower in women who regularly drink green tea, when compared to irregular tea drinkers, according to a study in the May 2005 issue of the journal “Carcinogenesis”; however, the authors of the study recommend more studies to understand the role of green tea in preventing high-estrogen related conditions such as breast cancer. Another study that was presented at the 2006 American Association of Cancer Research meeting revealed that in the laboratory green tea enhances the anti-estrogen effects of drugs such as tamoxifen 1. Tamoxifen is often prescribed to breast cancer patients. Thus, the study indicates that consuming green tea may be beneficial to breast cancer patients.
- The blood estrogen levels were 13 percent lower in women who regularly drink green tea, when compared to irregular tea drinkers, according to a study in the May 2005 issue of the journal “Carcinogenesis”; however, the authors of the study recommend more studies to understand the role of green tea in preventing high-estrogen related conditions such as breast cancer.
- Another study that was presented at the 2006 American Association of Cancer Research meeting revealed that in the laboratory green tea enhances the anti-estrogen effects of drugs such as tamoxifen 1.
Side Effects
Green tea contains significant amounts of caffeine, and excessive consumption of the beverage or supplements may lead to side effects such as:
- insomnia
- dizziness
- increased heart rate
- irritability
- anxiety
It may also cause vomiting and upset stomach. The University of Maryland Medical Center also warns pregnant and breastfeeding women and those with kidney disorders and stomach ulcers to avoid the drink 3. Green tea also interferes with certain blood-thinning, contraceptive and cancer medications.
Precautions
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Always talk to a doctor before using green tea for medicinal purposes. Choose a decaffeinated version if possible. Remember the production of green tea supplements in the United States is not regulated by the FDA. Hence, consult a pharmacist to find a product that has been tested for its safety and efficacy, or look for the USP logo, which is given to supplements that have been submitted for safety tests voluntarily.
- Always talk to a doctor before using green tea for medicinal purposes.
- Hence, consult a pharmacist to find a product that has been tested for its safety and efficacy, or look for the USP logo, which is given to supplements that have been submitted for safety tests voluntarily.
Related Articles
References
- "Proceedings of the American Association of Cancer Research"; Green Tea’s Effect on Anti-Estrogen Treatment; MR Sartippour, et al.; 2006
- "Medication Safety in Pregnancy and Breastfeeding"; Gideon Koren; 2007
- University of Maryland Medical Center: Green Tea
- Mereles D, Hunstein W. Epigallocatechin-3-gallate (EGCG) for Clinical Trials: More Pitfalls than Promises? Int J Mol Sci. 2011;12(9):5592-5603. doi:10.3390/ijms12095592
- National Cancer Institute. Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO).
- Samavat H, Ursin G, Emory TH, et al. A Randomized Controlled Trial of Green Tea Extract Supplementation and Mammographic Density in Postmenopausal Women at Increased Risk of Breast Cancer. Cancer Prev Res (Phila). 2017;10(12):710-718. doi:10.1158/1940-6207.CAPR-17-0187
- Baker KM, Bauer AC. Green Tea Catechin, EGCG Suppresses PCB 102-Induced Proliferation in Estrogen-Sensitive Breast Cancer Cells. Int J Breast Cancer. 2015;2015:163591. doi:10.1155/2015/163591
- Zhang JY, Liao YH, Lin Y, et al. Effects of tea consumption and the interactions with lipids on breast cancer survival. Breast Cancer Res Treat. 2019;176(3):679-686. doi:10.1007/s10549-019-05253-5
- Li MJ, Yin YC, Wang J, Jiang YF. Green tea compounds in breast cancer prevention and treatment. World J Clin Oncol. 2014;5(3):520-8. doi:10.5306/wjco.v5.i3.520
- Yiannakopoulou E. Interaction of Green Tea Catechins with Breast Cancer Endocrine Treatment: A Systematic Review. Pharmacology. 2014;94(5-6):245-248. doi:10.1159/000369170
- Dana-Farber Cancer Institute. Does sugar feed cancer?
- Jin Y, Zhao J, Kim EM, et al. Comprehensive Investigation of the Effects of Brewing Conditions in Sample Preparation of Green Tea Infusions. Molecules. 2019;24(9):1735. doi:10.3390/molecules24091735
- Chen X, Li Y, Lin Q, et al. Tea polyphenols induced apoptosis of breast cancer cells by suppressing the expression of Survivin. Scientific Reports. 2014. 4:4416. doi:10.1038/srep04416
- Crew KD, Ho KA, Brown P, et al. Effects of a green tea extract, Polyphenon E, on systemic biomarkers of growth factor signaling in women with hormone receptor-negative breast cancer. Journal of Human Nutrition and Dietetics. 2015. 28(3):272-82. doi:10.1111/jhn.12229
- Hashibe M, Galeone C, Buys SS, et al. Coffee, tea, caffeine intake, and the risk of cancer in the PLCO cohort. British Journal of Cancer. 2015. 113(5):809-16. doi:10.1038/bjc.2015.276
- National Cancer Institute Division of Cancer Prevention. Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO).
- Roomi MW, Kalinovsky T, Roomi NM, et al. In vitro and in vivo effects of a nutrient mixture on breast cancer progression. International Journal of Oncology 2014. 44(6):1933-44. doi:10.3892/ijo.2014.2379
- Samavat H, Ursin G, Emory T, et al. A Randomized Controlled Trial of Green Tea Extract Supplementation and Mammographic Density in Postmenopausal Women at Increased Risk of Breast Cancer. Cancer Prevention Research. 2017. 10(12):710-718. doi:10.1158/1940-6207.CAPR-17-0187
- Zhang JY, Liao YH, Lin Y, et al. Effects of tea consumption and the interactions with lipids on breast cancer survival. Breast Cancer Res Treat. 2019 May 16. doi:10.1007/s10549-019-05253-5
Writer Bio
A freelance writer and blogger since 2007, Shamala Pulugurtha's work has appeared in magazines such as the "Guide to Health and Healing" and prominent websites like Brain Blogger and NAMI California. Pulugurtha has a postgraduate degree in medical microbiology from Manipal Academy of Higher Education, India and has completed course work in psychology and health education.