Evidence map›Paper›PMID 32028419›Full record

SynthesisMedicine2020

Effect of green tea supplementation on blood pressure: A systematic review and meta-analysis of randomized controlled trials.

Renfan Xu, Ke Yang, Jie Ding, Guangzhi Chen

Abstract readMeta-AnalysisSystematic Review
PubMed Full text at PMC Publisher
In one paragraph

Synthesis in Medicine, 2020. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 27 papers, 3 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
27citing papers in PubMed, 3 pooled it
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

27 citing papers in PubMed, 3 syntheses or guidelines pooled it.

  1. Polyphenols for the Prevention or Management of Preeclampsia: A Systematic Review and Meta-Analysis.BJOG : an international journal of obstetrics and gynaecology · 2025
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  18. Oxidative Stress, Antioxidants and Hypertension.Antioxidants (Basel, Switzerland) · 2023
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4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

4 authors.

Renfan XuDepartment of Medical Ultrasound.
Ke YangDivision of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R. China.
Jie DingDivision of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R. China.
Guangzhi ChenDivision of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R. China.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundAlthough evidence from animal and observational studies has supported the beneficial effects of green tea intake for lowering blood pressure (BP), randomized placebo-controlled trials (RCTs) have yielded conflicting results. In this meta-analysis of RCTs, we aimed to assess the effects of green tea supplementation on measures of BP control.

methodsThe PubMed, Embase, and Cochrane Library databases were electronically searched from inception to August 2019 for all relevant studies. The results were pooled using the generic inverse-variance method with random-effects weighting and expressed as mean differences (MDs) with 95% confidence intervals (CIs). The quality of studies was assessed using the Jadad score. Publication bias was evaluated using funnel plots, Egger test, and Begg test.

resultsTwenty-four trials with 1697 subjects were included in the meta-analysis. The pooled results showed that green tea significantly lowered systolic BP (SBP; MD: -1.17 mm Hg; 95%CI: -2.18 to -0.16mm Hg; P = .02) and diastolic BP (DBP; MD: -1.24 mm Hg; 95%CI:-2.07 to -0.40mm Hg; P = .004). Significant heterogeneity was found for both SBP (I = 43%) and DBP (I = 57%). In addition, no evidence of significant publication bias was found from funnel plots or Egger test (P = .674 and P = .270 for SBP and DBP, respectively).

conclusionOverall, green tea significantly reduced SBP and DBP over the duration of the short-term trials. Larger and longer-term trials are needed to further investigate the effects of green tea supplementation on BP control and clinical events.

Indexed as

TeaBlood PressureDietary SupplementsHumansHypertensionRandomized Controlled Trials as TopicTea

Identifiers

PMID32028419
PMCPMC7015560

What OpenQuestion holds

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Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.