Health Library

Green Tea

Supplement Forms/Alternate Names:

  • Camellia sinensis

Introduction

Green tea is a bitter tea made from the leaves of a small shrub. Green tea has been used to lower cholesterol, blood pressure, and body mass index (BMI). Green tea is steeped and can be made into a hot or cold beverage. It can also be taken as a pill, powder, or extract.

Dosages

3 cups daily

What Research Shows

Likely Effective

May Be Effective

Unlikely to Be Effective

  • Gout —unlikely to reduce the risk L1

Not Enough Data to Assess

Editorial process and description of evidence categories can be found at EBSCO NAT Editorial Process.

Editorial process and description of evidence categories can be found at EBSCO NAT Editorial Process.

Safety Notes

It is likely safe for most adults to drink green tea in small doses for a short time. Women who are pregnant or breastfeeding should limit their intake of green tea. Not enough studies have been done to say whether it is safe to use for a long period. X1-X3

Interactions

Talk to your doctor about any supplements or therapy you would like to use. Some can interfere with treatment or make conditions worse.

References

REFA
Bladder Cancer

REFA1
Wang X, Lin YW, et al. A meta-analysis of tea consumption and the risk of bladder cancer. Urol Int. 2013;90(1):10-16.

REFB
Breast Cancer

REFB1
Gianfredi V, Nucci D, et al. Green Tea Consumption and Risk of Breast Cancer and Recurrence-A Systematic Review and Meta-Analysis of Observational Studies. Nutrients. 2018 Dec 3;10(12). pii: E1886.

REFB2
Yu S, Zhu L, et al. Green tea consumption and risk of breast cancer: A systematic review and updated meta-analysis of case-control studies. Medicine (Baltimore). 2019 Jul;98(27):e16147.

REFC
Cardiovascular Disease

REFC1
Hartley L, Flowers N, et al. Green and black tea for the primary prevention of cardiovascular disease. Cochrane Database Syst Rev. 2013;(6):CD009934.

REFC2
Pang J, Zhang Z, et al. Green tea consumption and risk of cardiovascular and ischemic related diseases: A meta-analysis. Int J Cardiol. 2016;202:967-974.

REFD
Cognitive Disorders

REFD1
Liu X, Du X, et al. Association between tea consumption and risk of cognitive disorders: A dose-response meta-analysis of observational studies. Oncotarget. 2017 Jun 27;8(26):43306-43321.

REFE
Colorectal Cancer

REFE1
Wang XJ, Zeng XT, et al. Association between green tea and colorectal cancer risk: a meta-analysis of 13 case-control studies. Asian Pac J Cancer Prev. 2012;13(7):3123-3127.

REFE2
Wang ZH, Gao QY, et al. Green tea and incidence of colorectal cancer: evidence from prospective cohort studies. Nutr Cancer. 2012;64(8):1143-1152.

REFE3
Chen Y, Wu Y, et al. An inverse association between tea consumption and colorectal cancer risk. Oncotarget. 2017 Jun 6;8(23):37367-37376.

REFF
Coronary Artery Disease

REFF1
Wang ZM, Zhou B, et al. Black and green tea consumption and the risk of coronary artery disease: a meta-analysis. Am J Clin Nutr. 2011 Mar;93(3):506-515.

REFG
Diabetes

REFG1
Liu K, Zhou R, et al. Effect of green tea on glucose control and insulin sensitivity: a meta-analysis of 17 randomized controlled trials. Am J Clin Nutr. 2013;98(2):340-348.

REFG2
Yang WS, Wang WY, et al. Tea consumption and risk of type 2 diabetes: a dose-response meta-analysis of cohort studies. Br J Nutr. 2014 Apr 28;111(8):1329-1339.

REFG3
Wang X, Tian J, et al. Effects of green tea or green tea extract on insulin sensitivity and glycaemic control in populations at risk of type 2 diabetes mellitus: a systematic review and meta-analysis of randomised controlled trials. J Hum Nutr Diet. 2014 Oct;27(5):501-512.

REFH
Diabetic Retinopathy

REFH1
Dow C, Mancini F, et al. Diet and risk of diabetic retinopathy: a systematic review. Eur J Epidemiol. 2018 Feb;33(2):141-156.

REFI
Esophageal Cancer

REFI1
Sang LX, Chang B, et al. Green tea consumption and risk of esophageal cancer: a meta-analysis of published epidemiological studies. Nutr Cancer. 2013;65(6):802-812.

REFI2
Zheng JS, Yang J, et al. Effects of green tea, black tea, and coffee consumption on the risk of esophageal cancer: a systematic review and meta-analysis of observational studies. Nutr Cancer. 2013;65(1):1-16.

REFJ
External Anogenital Warts

REFJ1
Tzellos TG, Sardeli C, et al. Efficacy, safety and tolerability of green tea catechins in the treatment of external anogenital warts: a systematic review and meta-analysis. J Eur Acad Dermatol Venereol. 2011 Mar;25(3):345-353.

REFK
Gastric Cancer

REFK1
Huang Y, Chen H, et al. Association between green tea intake and risk of gastric cancer: a systematic review and dose-response meta-analysis of observational studies. Public Health Nutr. 2017 Dec;20(17):3183-3192.

REFL
Gout

REFL1
Zhang Y, Cui Y, et al. Is tea consumption associated with the serum uric acid level, hyperuricemia or the risk of gout? A systematic review and meta-analysis. BMC Musculoskelet Disord. 2017 Feb 28;18(1):95.

REFM
High Blood Pressure

REFM1
Khalesi S, Sun J, et al. Green tea catechins and blood pressure: a systematic review and meta-analysis of randomised controlled trials. Eur J Nutr. 2014 Sep;53(6):1299-311.

REFM2
Liu G, Mi XN, et al. Effects of tea intake on blood pressure: a meta-analysis of randomised controlled trials. Br J Nutr. 2014 Oct 14;112(7):1043-1054.

REFM3
Onakpoya I, Spencer E, et al. The effect of green tea on blood pressure and lipid profile: a systematic review and meta-analysis of randomized clinical trials. Nutr Metab Cardiovasc Dis. 2014;24(8):823-836.

REFM4
Peng X, Zhou R, et al. Effect of green tea consumption on blood pressure: a meta-analysis of 13 randomized controlled trials. Sci Rep. 2014;4:6251.

REFN
High Cholesterol

REFN1
Zheng XX, Xu YL, et al. Green tea intake lowers fasting serum total and LDL cholesterol in adults: a meta-analysis of 14 randomized controlled trials. Am J Clin Nutr. 2011 Aug;94(2):601-610.

REFN2
Kim A, Chiu A, et al. Green tea catechins decrease total and low-density lipoprotein cholesterol: a systematic review and meta-analysis. J Am Diet Assoc. 2011;111(11):1720-1729.

REFN3
Khalesi S, Sun J, et al. Green tea catechins and blood pressure: a systematic review and meta-analysis of randomised controlled trials. Eur J Nutr. 2014 Sep;53(6):1299-311.

REFO
Inflammatory Bowel Disease

REFO1
Rossi RE, Whyand T, et al. The role of dietary supplements in inflammatory bowel disease: a systematic review. Eur J Gastroenterol Hepatol. 2016 Dec;28(12):1357-1364.

REFP
Liver Cancer

REFP1
Fon Sing M, Yang WS, et al. Epidemiological studies of the association between tea drinking and primary liver cancer: a meta-analysis. Eur J Cancer Prev. 2011 May;20(3):157-165.

REFP2
Ni CX, Gong H, et al. Green Tea Consumption and the Risk of Liver Cancer: A Meta-Analysis. Nutr Cancer. 2017 Feb-Mar;69(2):211-220.

REFQ
Lung Cancer

REFQ1
Wang L, Zhang X, et al. Tea consumption and lung cancer risk: a meta-analysis of case-control and cohort studies. Nutrition. 2014 Oct;30(10):1122-1127.

REFR
Nonalcoholic Fatty Liver Disease

REFR1
Mansour- Ghanaei F, Hadi A, et al. Green tea as a safe alternative approach for nonalcoholic fatty liver treatment: A systematic review and meta-analysis of clinical trials. Phytother Res. 2018;32(10):1876-1884.

REFS
Obesity

REFS1
Hursel R, Viechtbauer W, et al. The effects of green tea on weight loss and weight maintenance: a meta-analysis. Int J Obes (Lond). 2009 Sep;33(9):956-961.

REFS2
Jurgens TM, Whelan AM, et al. Green tea for weight loss and weight maintenance in overweight or obese adults. Cochrane Database Syst Rev. 2012;12:CD008650.

REFS3
Yuan F, Dong H, et al. Effects of green tea on lipid metabolism in overweight or obese people: A meta-analysis of randomized controlled trials. Mol Nutr Food Res. 2018;62(1):10.

REFT
Oral Cancer

REFT1
Wang W, Yang Y, et al. Association of tea consumption and the risk of oral cancer: a meta-analysis. Oral Oncol. 2014 Apr;50(4):276-281.

REFU
Oral Hygiene

REFU1
Mathur A, Gopalakrishnan D, et al. Efficacy of green tea-based mouthwashes on dental plaque and gingival inflammation: A systematic review and meta-analysis. Indian J Dent Res. 2018 Mar-Apr;29(2):225-232.

REFV
Polycystic Ovary Syndrome

REFV1
Arentz S, Smith CA, et al. Nutritional supplements and herbal medicines for women with polycystic ovary syndrome; a systematic review and meta-analysis. BMC Complement Altern Med. 2017 Nov 25;17(1):500.

REFW
Prostate Cancer

REFW1
Jacob SA, Khan TM, et al. The Effect of Green Tea Consumption on Prostate Cancer Risk and Progression: A Systematic Review. Nutr Cancer. 2017 Apr;69(3):353-364.

REFW2
Guo Y, Zhi F, et al. Green tea and the risk of prostate cancer: A systematic review and meta-analysis. Medicine (Baltimore). 2017 Mar;96(13):e6426.

REFX
Safety

REFX1
Izzo AA. Interactions between herbs and conventional drugs: overview of the clinical data. Med Princ Pract. 2012;21(5):404-428.

REFX2
Asher GN, Corbett AH, et al. Common Herbal Dietary Supplement-Drug Interactions. Am Fam Physician. 2017 Jul 15;96(2):101-107.

REFX3
Hu J, Webster D, et al. The safety of green tea and green tea extract consumption in adults - Results of a systematic review. Regul Toxicol Pharmacol. 2018 Jun;95:412-433.

  • EBSCO NAT Review Board
  • 202206