Green tea catechins and blood pressure: a systematic review and meta-analysis of randomised controlled trials
Although previous literature has reported that regular green tea consumption may improve blood pressure, the evidence from these studies is not consistent. The present study systematically reviewed randomised controlled trials and examined the effect of green tea consumption on blood pressure using meta-analysis.
Search of ProQuest, PubMed, Scopus and Cochrane Library (CENTERAL) was conducted, to identify eligible articles. Articles from 1995 to 2013 were included. A random-effect model was chosen to calculate the effect of combined trials.
Thirteen studies were included in the meta-analysis. Green tea consumption significantly changed systolic blood pressure, by −2.08 mm Hg (95 % CI −3.06, −1.05), and diastolic blood pressure, by −1.71 mm Hg (95 % CI −2.86, −0.56), compared to the control. Changes in lipid profile, blood glucose and body mass index were also assessed in the meta-analysis. A significant reduction was found in total cholesterol (−0.15 mmol/L [95 % CI −0.27, −0.02]) and low-density lipoprotein cholesterol (−0.16 mmol/L [95 % CI −0.22, −0.09]). Changes in other parameters did not reach statistical significance. Subgroup analysis suggested a greater reduction in both systolic and diastolic blood pressure in studies that included participants with a baseline mean systolic blood pressure of ≥130 mm Hg, and studies involving consuming green tea as an extract.
The present meta-analysis suggests that green tea and its catechins may improve blood pressure, and the effect may be greater in those with systolic blood pressure ≥130 mm Hg. The meta-analysis also suggests that green tea catechins may improve total and low-density lipoprotein cholesterol.
KeywordsGreen tea Blood Pressure Lipid profile Systematic review Meta-analysis
- 1.WHO (2002) World Health Organization. World Health Report 2002. Reducing risks, promoting healthy life. Geneva, Switzerland. http://wwww.hoint/whr/2002/en
- 2.WHO (2008) Global health observatory (GHO). Raised blood pressure. http://www.who.int/gho/ncd/risk_factors/blood_pressure_prevalence_text/en/index.html
- 5.Qureshi A, Sapkota B (2011) Blood pressure reduction in secondary stroke prevention. Continuum (Minneapolis, Minn) 17 (6 2ndary Stroke Prevention):1233Google Scholar
- 7.Hooper L, Kroon PA, Rimm EB, Cohn JS, Harvey I, Le Cornu KA, Ryder JJ, Hall WL, Cassidy A (2008) Flavonoids, flavonoid-rich foods, and cardiovascular risk: a meta-analysis of randomized controlled trials. Am J Clin Nutr 88(1):38–50Google Scholar
- 10.Bhardwaj P, Khanna D (2013) Green tea catechins: defensive role in cardiovascular disorders. Chin J Nat Med 11(4):345–353Google Scholar
- 17.Auvichayapat P, Prapochanung M, Tunkamnerdthai O, Sripanidkulchai B-O, Auvichayapat N, Thinkhamrop B, Kunhasura S, Wongpratoom S, Sinawat S, Hongprapas P (2008) Effectiveness of green tea on weight reduction in obese Thais: a randomized, controlled trial. Physiol Behav 93(3):486–491CrossRefGoogle Scholar
- 19.Liberati A, Moher D, Altman DG, Tetzlaff J, Mulrow C, Gøtzsche PC, Ioannidis JPA, Clarke M, Devereaux PJ, Kleijnen J (2009) The PRISMA statement for reporting systematic reviews and meta-analyses of studies that evaluate health care interventions: explanation and elaboration. PLoS Med 6(7):e1000100. doi:10.1371/journal.pmed.1000100 CrossRefGoogle Scholar
- 24.Higgins J, Green S (2011) Cochrane handbook for systematic reviews of interventions version 5.1.0 [updated March 2011]. The Cochrane Collaboration, Medical Research Council, UKGoogle Scholar
- 28.Sone T, Kuriyama S, Nakaya N, Hozawa A, Shimazu T, Nomura K, Rikimaru S, Tsuji I (2011) Randomized controlled trial for an effect of catechin-enriched green tea consumption on adiponectin and cardiovascular disease risk factors. Food Nutr Res 55:1–10. doi:10.3402/fnr.v55i0.8326 CrossRefGoogle Scholar
- 31.Bogdanski P, Suliburska J, Szulinska M, Stepien M, Pupek-Musialik D, Jablecka A (2012) Green tea extract reduces blood pressure, inflammatory biomarkers, and oxidative stress and improves parameters associated with insulin resistance in obese, hypertensive patients. Nutr Res 32(6):421–427. doi:10.1016/j.nutres.2012.05.007 CrossRefGoogle Scholar
- 32.Frank J, George TW, Lodge JK, Rodriguez-Mateos AM, Spencer JP, Minihane AM, Rimbach G (2009) Daily consumption of an aqueous green tea extract supplement does not impair liver function or alter cardiovascular disease risk biomarkers in healthy men. J Nutr 139(1):58–62. doi:10.3945/jn.108.096412 CrossRefGoogle Scholar
- 37.Suliburska J, Bogdanski P, Szulinska M, Stepien M, Pupek-Musialik D, Jablecka A (2012) Effects of green tea supplementation on elements, total antioxidants, lipids, and glucose values in the serum of obese patients. Biol Trace Elem Res 149(3):315–322. doi:10.1007/s12011-012-9448-z CrossRefGoogle Scholar
- 50.Ikeda I, Kobayashi M, Hamada T, Tsuda K, Goto H, Imaizumi K, Nozawa A, Sugimoto A, Kakuda T (2003) Heat-epimerized tea catechins rich in gallocatechin gallate and catechin gallate are more effective to inhibit cholesterol absorption than tea catechins rich in epigallocatechin gallate and epicatechin gallate. J Agric Food Chem 51(25):7303–7307CrossRefGoogle Scholar
- 56.Barter P, Gotto AM, LaRosa JC, Maroni J, Szarek M, Grundy SM, Kastelein JJP, Bittner V, Fruchart J-C, Treating New Targets I, Treating to New Targets I (2007) HDL cholesterol, very low levels of LDL cholesterol, and cardiovascular events. N Engl J Med 357(13):1301–1310. doi:10.1056/NEJMoa064278 CrossRefGoogle Scholar