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Effect of green tea consumption on blood pressure: a meta-analysis of 13 randomized controlled trials.

Peng X, Zhou R, Wang B, Yu X, Yang X, Liu K, Mi M - Sci Rep (2014)

Bottom Line: The studies investigating the effects of green tea on blood pressure (BP) have generated inconsistent results.Subgroup analyses further suggested that the positive effect of green tea polyphenols on BP was only showed in studies using a low-dose green tea polyphenol, with the long-term intervention duration or ruling out the confounding effects of caffeine.The meta-analysis suggested that green tea consumption had a favorable effect on decrease of BP.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Epidemiology and Health Statistics, Institute of Public Health, Chengdu Medical College, Chengdu 610083, Sichuan, China [2] Research Center for Nutrition and Food Safety, Institute of Military Preventive Medicine, Third Military Medical University, Chongqing Key Laboratory of Nutrition and Food Safety, Chongqing Medical Nutrition Research Center, Chongqing 400038, China [3].

ABSTRACT
The studies investigating the effects of green tea on blood pressure (BP) have generated inconsistent results. The aim of this study is to quantitatively evaluate the effects of green tea on BP control. PubMed, Embase, and the Cochrane Library (updated to March 2014) were searched for randomized controlled trials evaluating the effects of green tea on BP. Pooled effect of green tea consumption on BP was evaluated using fixed-effects or random-effects model. Thirteen trials comprising a total of 1,367 subjects were included in the current meta-analysis. The overall outcome of the meta-analysis suggested that green tea consumption significantly decrease systolic blood pressure (SBP) level by -1.98 mmHg (95% CI: -2.94, -1.01 mmHg; P < 0.001). Compared with the control group, green tea also showed a significant lowering effect on diastolic blood pressure (DBP) in treatment group (-1.92 mmHg; 95% CI: -3.17, -0.68 mmHg; P = 0.002). Subgroup analyses further suggested that the positive effect of green tea polyphenols on BP was only showed in studies using a low-dose green tea polyphenol, with the long-term intervention duration or ruling out the confounding effects of caffeine. The meta-analysis suggested that green tea consumption had a favorable effect on decrease of BP.

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Related in: MedlinePlus

Flow diagram showing the number of citations retrieved by individual searches of articles included in the review.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4150247&req=5

f1: Flow diagram showing the number of citations retrieved by individual searches of articles included in the review.

Mentions: Detailed processes of the relevant study selection are shown in Fig. 1. A total of 186 reports were initially identified, and 153 articles were excluded either because of duplication or because they were clearly not relevant to the current meta-analysis after carefully reviewing the titles and abstracts. Thus, 33 articles remained for an in-depth examination. Among these 33 articles, 20 were further excluded for the following reasons: 8 were due to their short duration (<1 day), 6 were due to no data of SBP or DBP, and 6 were discarded because the green tea extract was given as part of a multi-component supplement. Thus, 13 articles were ultimately selected for inclusion in the meta-analysis11121314151617181920212223.


Effect of green tea consumption on blood pressure: a meta-analysis of 13 randomized controlled trials.

Peng X, Zhou R, Wang B, Yu X, Yang X, Liu K, Mi M - Sci Rep (2014)

Flow diagram showing the number of citations retrieved by individual searches of articles included in the review.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4150247&req=5

f1: Flow diagram showing the number of citations retrieved by individual searches of articles included in the review.
Mentions: Detailed processes of the relevant study selection are shown in Fig. 1. A total of 186 reports were initially identified, and 153 articles were excluded either because of duplication or because they were clearly not relevant to the current meta-analysis after carefully reviewing the titles and abstracts. Thus, 33 articles remained for an in-depth examination. Among these 33 articles, 20 were further excluded for the following reasons: 8 were due to their short duration (<1 day), 6 were due to no data of SBP or DBP, and 6 were discarded because the green tea extract was given as part of a multi-component supplement. Thus, 13 articles were ultimately selected for inclusion in the meta-analysis11121314151617181920212223.

Bottom Line: The studies investigating the effects of green tea on blood pressure (BP) have generated inconsistent results.Subgroup analyses further suggested that the positive effect of green tea polyphenols on BP was only showed in studies using a low-dose green tea polyphenol, with the long-term intervention duration or ruling out the confounding effects of caffeine.The meta-analysis suggested that green tea consumption had a favorable effect on decrease of BP.

View Article: PubMed Central - PubMed

Affiliation: 1] Department of Epidemiology and Health Statistics, Institute of Public Health, Chengdu Medical College, Chengdu 610083, Sichuan, China [2] Research Center for Nutrition and Food Safety, Institute of Military Preventive Medicine, Third Military Medical University, Chongqing Key Laboratory of Nutrition and Food Safety, Chongqing Medical Nutrition Research Center, Chongqing 400038, China [3].

ABSTRACT
The studies investigating the effects of green tea on blood pressure (BP) have generated inconsistent results. The aim of this study is to quantitatively evaluate the effects of green tea on BP control. PubMed, Embase, and the Cochrane Library (updated to March 2014) were searched for randomized controlled trials evaluating the effects of green tea on BP. Pooled effect of green tea consumption on BP was evaluated using fixed-effects or random-effects model. Thirteen trials comprising a total of 1,367 subjects were included in the current meta-analysis. The overall outcome of the meta-analysis suggested that green tea consumption significantly decrease systolic blood pressure (SBP) level by -1.98 mmHg (95% CI: -2.94, -1.01 mmHg; P < 0.001). Compared with the control group, green tea also showed a significant lowering effect on diastolic blood pressure (DBP) in treatment group (-1.92 mmHg; 95% CI: -3.17, -0.68 mmHg; P = 0.002). Subgroup analyses further suggested that the positive effect of green tea polyphenols on BP was only showed in studies using a low-dose green tea polyphenol, with the long-term intervention duration or ruling out the confounding effects of caffeine. The meta-analysis suggested that green tea consumption had a favorable effect on decrease of BP.

Show MeSH
Related in: MedlinePlus