Effect of green tea supplementation on blood pressure in adults: a GRADE-assessed systematic review and dose-response meta-analysis of randomised controlled trials

Background Hypertension (HTN) is a leading contributor to cardiovascular disease (CVD). Green tea has been proposed as a natural intervention for blood pressure (BP) management due to its antioxidant content. This study aimed to systematically evaluate the effect of green tea supplementation on syst...

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Main Authors: Mahshid Rezaei, Neda Akhavan, Fereshteh Fathi, Seyyed Mohammad Alavi, Mahdiyeh Fadaii, Mohammad Jafar Dehzad, Moein Askarpour
Format: Article
Language:English
Published: Taylor & Francis Group 2025-12-01
Series:Blood Pressure
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Online Access:https://www.tandfonline.com/doi/10.1080/08037051.2025.2517122
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author Mahshid Rezaei
Neda Akhavan
Fereshteh Fathi
Seyyed Mohammad Alavi
Mahdiyeh Fadaii
Mohammad Jafar Dehzad
Moein Askarpour
author_facet Mahshid Rezaei
Neda Akhavan
Fereshteh Fathi
Seyyed Mohammad Alavi
Mahdiyeh Fadaii
Mohammad Jafar Dehzad
Moein Askarpour
author_sort Mahshid Rezaei
collection DOAJ
description Background Hypertension (HTN) is a leading contributor to cardiovascular disease (CVD). Green tea has been proposed as a natural intervention for blood pressure (BP) management due to its antioxidant content. This study aimed to systematically evaluate the effect of green tea supplementation on systolic (SBP) and diastolic blood pressure (DBP) using a meta-analysis of randomised controlled trials (RCTs).Methods Eligibility criteria were defined using the PICOS framework. PubMed, Scopus, and Web of Science were searched through January 2024 for randomised controlled trials in adults (≥18 years) comparing green tea supplementation with control or placebo, reporting pre- and post-intervention systolic and diastolic blood pressure (SBP and DBP). Weighted mean differences (WMDs) and 95% confidence intervals (CIs) were pooled using random-effects models. Subgroup analyses and dose-response analyses were performed.Results A total of 36 RCTs were included. Green tea reduced SBP (WMD: −1.08 mmHg; 95% CI: −1.98, −0.18; I2 = 85.0%) and DBP (WMD: −1.09 mmHg; 95% CI: −1.67, −0.50; I2 = 74.0%). Subgroup analyses showed stronger effects in participants with elevated baseline BP (SBP ≥120 mmHg), those consuming <500 mg/day green tea, studies ≤8 weeks, Asian populations, and women. No clear association was found between BP changes and tea dose or intervention duration.Conclusion Green tea supplementation is associated with modest reductions in SBP and DBP. Given the heterogeneity and lack of clear dose-duration effects, green tea is better considered a complementary approach for managing blood pressure.
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spelling doaj-art-aebc7a2ce2cd479f9be46bb38268f44d2025-08-20T02:22:50ZengTaylor & Francis GroupBlood Pressure0803-70511651-19992025-12-0134110.1080/08037051.2025.2517122Effect of green tea supplementation on blood pressure in adults: a GRADE-assessed systematic review and dose-response meta-analysis of randomised controlled trialsMahshid Rezaei0Neda Akhavan1Fereshteh Fathi2Seyyed Mohammad Alavi3Mahdiyeh Fadaii4Mohammad Jafar Dehzad5Moein Askarpour6Nutrition and Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, IranDepartment of Kinesiology and Nutrition Sciences, School of Integrated Health Sciences, University of Nevada, Las Vegas, NV, USADepartment of Persian Medicine, Mazandaran University of Medical Sciences, Sari, IranDepartment of Clinical Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Science, Tehran, IranMidwifery of Savadkuh Health Network, Mazandaran University of Medical Sciences, Sari, IranDepartment of Clinical Nutrition, School of Nutritional Sciences and Dietetics, Shiraz University of Medical Sciences, Shiraz, IranSocial Determinants of Health Research Center, Institute for Futures Studies in Health, Kerman University of Medical Sciences, Kerman, IranBackground Hypertension (HTN) is a leading contributor to cardiovascular disease (CVD). Green tea has been proposed as a natural intervention for blood pressure (BP) management due to its antioxidant content. This study aimed to systematically evaluate the effect of green tea supplementation on systolic (SBP) and diastolic blood pressure (DBP) using a meta-analysis of randomised controlled trials (RCTs).Methods Eligibility criteria were defined using the PICOS framework. PubMed, Scopus, and Web of Science were searched through January 2024 for randomised controlled trials in adults (≥18 years) comparing green tea supplementation with control or placebo, reporting pre- and post-intervention systolic and diastolic blood pressure (SBP and DBP). Weighted mean differences (WMDs) and 95% confidence intervals (CIs) were pooled using random-effects models. Subgroup analyses and dose-response analyses were performed.Results A total of 36 RCTs were included. Green tea reduced SBP (WMD: −1.08 mmHg; 95% CI: −1.98, −0.18; I2 = 85.0%) and DBP (WMD: −1.09 mmHg; 95% CI: −1.67, −0.50; I2 = 74.0%). Subgroup analyses showed stronger effects in participants with elevated baseline BP (SBP ≥120 mmHg), those consuming <500 mg/day green tea, studies ≤8 weeks, Asian populations, and women. No clear association was found between BP changes and tea dose or intervention duration.Conclusion Green tea supplementation is associated with modest reductions in SBP and DBP. Given the heterogeneity and lack of clear dose-duration effects, green tea is better considered a complementary approach for managing blood pressure.https://www.tandfonline.com/doi/10.1080/08037051.2025.2517122Meta-analysisrandomised controlled trialsgreen teasystolic blood pressurediastolic blood pressure
spellingShingle Mahshid Rezaei
Neda Akhavan
Fereshteh Fathi
Seyyed Mohammad Alavi
Mahdiyeh Fadaii
Mohammad Jafar Dehzad
Moein Askarpour
Effect of green tea supplementation on blood pressure in adults: a GRADE-assessed systematic review and dose-response meta-analysis of randomised controlled trials
Blood Pressure
Meta-analysis
randomised controlled trials
green tea
systolic blood pressure
diastolic blood pressure
title Effect of green tea supplementation on blood pressure in adults: a GRADE-assessed systematic review and dose-response meta-analysis of randomised controlled trials
title_full Effect of green tea supplementation on blood pressure in adults: a GRADE-assessed systematic review and dose-response meta-analysis of randomised controlled trials
title_fullStr Effect of green tea supplementation on blood pressure in adults: a GRADE-assessed systematic review and dose-response meta-analysis of randomised controlled trials
title_full_unstemmed Effect of green tea supplementation on blood pressure in adults: a GRADE-assessed systematic review and dose-response meta-analysis of randomised controlled trials
title_short Effect of green tea supplementation on blood pressure in adults: a GRADE-assessed systematic review and dose-response meta-analysis of randomised controlled trials
title_sort effect of green tea supplementation on blood pressure in adults a grade assessed systematic review and dose response meta analysis of randomised controlled trials
topic Meta-analysis
randomised controlled trials
green tea
systolic blood pressure
diastolic blood pressure
url https://www.tandfonline.com/doi/10.1080/08037051.2025.2517122
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