Different applications forms of green tea ( Camellia sinensis (L.) Kuntze) for the treatment of periodontitis: a systematic review and meta‐analysis

Influenza is one of the most serious respiratory viral infections worldwide. Although several studies have reported that green tea catechins (GTCs) might prevent influenza virus infection, this remains controversial. We performed a systematic review and meta-analysis of eight studies with 5,048 participants that examined the effect of GTC administration on influenza prevention. In a random-effects meta-analysis of five RCTs, 884 participants treated with GTCs showed statistically significant effects on the prevention of influenza infection compared to the control group (risk ratio (RR) 0.67, 95%CIs 0.51–0.89, P = 0.005) without evidence of heterogeneity (I2= 0%, P = 0.629). Similarly, in three cohort studies with 2,223 participants treated with GTCs, there were also statistically significant effects (RR 0.52, 95%CIs 0.35–0.77, P = 0.001) with very low evidence of heterogeneity (I2 = 3%, P = 0.358). Additionally, the overall effect in the subgroup analysis of gargling and orally ingested items (taking capsules and drinking) showed a pooled RR of 0.62 (95% CIs 0.49–0.77, P = 0.003) without heterogeneity (I2= 0%, P = 0.554). There were no obvious publication biases (Egger’s test (P = 0.138) and Begg’s test (P = 0.103)). Our analysis suggests that green tea consumption is effective in the prophylaxis of influenza infections. To confirm the findings before implementation, longitudinal clinical trials with specific doses of green tea consumption are warranted.

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Green tea and green tea extract in oncological treatment: A systematic review

International Journal for Vitamin and Nutrition Research ◽

10.1024/0300-9831/a000698 ◽

2021 ◽

pp. 1-13

Author(s):

Fanny Wiese ◽

Sabine Kutschan ◽

Jennifer Doerfler ◽

Viktoria Mathies ◽

Jens Buentzel ◽

...

Keyword(s):

Systematic Review ◽

Green Tea ◽

Methodological Quality ◽

Meta Analysis ◽

Specific Antigen ◽

Intervention Group ◽

Epigallocatechin Gallate ◽

Oncological Treatment ◽

Complementary Method ◽

Tea Extract

Abstract. Purpose: Teas are an essential part of traditional phytotherapy. The aim of this systematic review is to assess the clinical evidence using green tea catechins in cancer care. Methods: A systematic search was conducted searching five electronic databases concerning the effectiveness and risks of epigallocatechin gallate (EGCG) on cancer patients. Results: Seven studies with 371 patients were included. Patients were mainly suffering from breast and prostate cancer. Dosing ranged from 28 mg to 1600 mg EGCG, intervention time from 7 days to 6 months with different applications (topical 2 studies; oral 5 studies). The studies showed heterogeneous methodological quality and results leading not to conduct a meta-analysis. There was a small decrease in prostate-specific-antigen levels in one study (N=60; T0:(mean±SD) 9.6±5.2 ng/ml, T1: 8.4±4.3 ng/ml vs. T0: 9.9±8.5 ng/ml, T1: 10.0±9.0 ng/ml; p=0.04), whereas in a second study only a trend was seen. Topical green tea was as effective as metronidazole powder in reducing the odor of fungating malignant wounds (1 study; N=30) with a consequent increase in quality of life (QoL) (p<0.001), improvement of appetite (p<0.001), malodorous control (p<0.001), social activities (p<0.001). Radiotherapy-induced diarrhea was lower in the green tea intervention group compared to placebo (1 study; N=42; week 4+5: without diarrhea p=0.002). Conclusions: The studies suggest that EGCG is as effective as a local antibiotic in malodorous control and improvement of QoL of fungating malignant wounds. Green tea could be a possible complementary method for treating acute radiation-induced diarrhea. Due to limitations, further studies with higher methodological quality and larger sample sizes are needed.

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Effect of Green Tea on Plasma Adiponectin Levels: A Systematic Review and Meta-analysis of Randomized Controlled Clinical Trials

Journal of the American College of Nutrition ◽

10.1080/07315724.2017.1333470 ◽

2017 ◽

Vol 36 (7) ◽

pp. 541-548 ◽

Cited By ~ 8

Author(s):

Fahimeh Haghighatdoost ◽

B. Fatemeh Nobakht M. Gh ◽

Mitra Hariri

Keyword(s):

Systematic Review ◽

Clinical Trials ◽

Green Tea ◽

Meta Analysis ◽

Controlled Clinical Trials ◽

Plasma Adiponectin ◽

Randomized Controlled Clinical Trials ◽

Randomized Controlled

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Green tea catechins and blood pressure: a systematic review and meta-analysis of randomised controlled trials

European Journal of Nutrition ◽

10.1007/s00394-014-0720-1 ◽

2014 ◽

Vol 53 (6) ◽

pp. 1299-1311 ◽

Cited By ~ 55

Author(s):

Saman Khalesi ◽

Jing Sun ◽

Nicholas Buys ◽

Arash Jamshidi ◽

Elham Nikbakht-Nasrabadi ◽

...

Keyword(s):

Systematic Review ◽

Blood Pressure ◽

Green Tea ◽

Randomised Controlled Trials ◽

Meta Analysis ◽

Controlled Trials ◽

Tea Catechins ◽

Green Tea Catechins ◽

Randomised Controlled

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Tea Flavonoids and Risk of Cardiovascular and All-Cause Mortality: A Systematic Review and Meta-Analysis

Proceedings of The Nutrition Society ◽

10.1017/s0029665120001573 ◽

2020 ◽

Vol 79 (OCE2) ◽

Cited By ~ 1

Author(s):

Ding Ding Wang ◽

Aedin Cassidy ◽

Mario G. Ferruzzi ◽

Paul Jacques ◽

Elizabeth Johnson ◽

...

Keyword(s):

Systematic Review ◽

Cohort Studies ◽

Green Tea ◽

Lower Risk ◽

Meta Analysis ◽

Black Tea ◽

Tea Consumption ◽

Prospective Cohort Studies ◽

All Cause Mortality ◽

Meta Regression

AbstractThere is increasing evidence that both black and green tea are beneficial for prevention of cardiovascular disease (CVD). We conducted a systematic review and meta-analysis evaluating the effects of tea flavonoids on cardiovascular (CVD) and all-cause mortality outcomes.Searches across five databases including PubMed and Embase were conducted through November 2018 to identify randomized controlled trials (RCTs) and prospective cohort studies reporting cardiovascular and all-cause mortality outcomes. Two investigators independently conducted abstract and full-text screenings, data extractions, and risk of bias (ROB) assessments using the Nutrition Evidence Library Bias Assessment Tool (NEL BAT). Mixed-effects dose-response meta-regression and standard random-effects meta-analyses for outcomes with ≥ 4 studies were performed. 0 RCTs and 38 prospective cohort studies were included in the systematic review. NEL BAT scores ranged from 0–15 (0 being the lowest risk). Our linear meta-regression model showed that each cup increase in daily tea consumption (about 280 mg and 338 mg of total flavonoids for black and green tea, respectively) was associated with 3–4% lower risk of CVD mortality (predicted adjusted RR = 0.96; CI 0.93–0.99 for green tea and RR = 0.97; CI 0.94–0.99 for black tea). Furthermore, eachcup increase in daily tea consumption was associated a 2% lower risk of all-cause mortality (predicted adjusted relative risk (RR) = 0.98; 95% CI 0.97–0.99 for black tea and RR = 0.98; CI 0.96–0.99 for green tea, respectively). Two studies reported multivariable Cox regression analysis results for the relationship between black tea intake and risks of all-cause mortality outcomes. The results from these two studies were combined with our linear meta-regression result in a random-effects model meta-analysis and showed that each cup increase in daily black tea consumption was associated with an average of 3% lower risk of all-cause mortality (pooled adjusted RR = 0.97; 95% CI 0.87- 1.00) with large heterogeneity (I2 = 81.4%; p = 0.005). Current evidence indicates that increased tea consumption may reduce cardiovascular and all-cause mortality in a dose-response manner. This systematic review was registered on PROSPERO.

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