Dataset Information

Effects of green tea consumption on glycemic control: a systematic review and meta-analysis of randomized controlled trials.

ABSTRACT:

Background

The results of human clinical trials investigating the effects of green tea on glycemic control are inconsistent.

Methods

We conducted a systematic review and meta-analysis of RCTs that examined the effects of green tea supplementation on glycemic control. A literature search in PubMed, Embase, and Cochrane Library databases for RCTs that investigated the effect of green tea consumption on glycemic control was performed up to February 2020. A random-effects model was used to estimate weighted mean difference (WMD) with 95% confidence intervals (CIs).

Results

Twenty-seven trials involving 2194 subjects were included in the meta-analysis. The pooled results showed that green tea significantly lowered fasting blood glucose by - 1.44 mg/dL (95%CI:-2.26, - 0.62 mg/dL; P < 0.001) with no obvious heterogeneity (I ² = 7.7%). However, green tea consumption did not significantly affect fasting insulin and HbA1c values. The mean differences were - 0.46μIU/mL (95% CI: - 1.10, 0.17μIU/mL; P = 0.21) for fasting insulin and - 0.06%; (95% CI: - 0.12, 0.01%; P = 0.07) for HbA_1c concentrations. Heterogeneity was significant in fasting insulin (I ² = 46.8%) and mild in HbA_1c (I ² = 1.7%).

Conclusions

In short-term trials, green tea supplementation significantly reduced fasting glucose, but had no significant effect on fasting insulin and HbA_1c. Long-term trials assessing the effects of green tea supplementation on glycemic control are needed.

SUBMITTER: Xu R

PROVIDER: S-EPMC7350188 | biostudies-literature | 2020

REPOSITORIES: biostudies-literature

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Publications

Effects of green tea consumption on glycemic control: a systematic review and meta-analysis of randomized controlled trials.

Xu Renfan R Bai Yang Y Yang Ke K Chen Guangzhi G

Nutrition & metabolism 20200710

<h4>Background</h4>The results of human clinical trials investigating the effects of green tea on glycemic control are inconsistent.<h4>Methods</h4>We conducted a systematic review and meta-analysis of RCTs that examined the effects of green tea supplementation on glycemic control. A literature search in PubMed, Embase, and Cochrane Library databases for RCTs that investigated the effect of green tea consumption on glycemic control was performed up to February 2020. A random-effects model was us ...[more]

PMID: 32670385

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Project description:Bread is a major source of grain-derived carbohydrates worldwide. High intakes of refined grains, low in dietary fiber and high in glycemic index, are linked with increased risk for type 2 diabetes mellitus (T2DM) and other chronic diseases. Hence, improvements in the composition of bread could influence population health. This systematic review evaluated the effect of regular consumption of reformulated breads on glycemic control among healthy adults, adults at cardiometabolic risk or with manifest T2DM. A literature search was performed using MEDLINE, Embase, Web of Science and the Cochrane Central Register of Controlled Trials. Eligible studies employed a bread intervention (≥2 wk) in adults (healthy, at cardiometabolic risk or manifest T2DM) and reported glycemic outcomes (fasting blood glucose, fasting insulin, HOMA-IR, HbA1c, and postprandial glucose responses). Data were pooled using generic inverse variance with random-effects model and presented as mean difference (MD) or standardized MD between treatments with 95% CIs. Twenty-two studies met the inclusion criteria (n = 1037 participants). Compared with "regular" or comparator bread, consumption of reformulated intervention breads yielded lower fasting blood glucose concentrations (MD: -0.21 mmol/L; 95% CI: -0.38, -0.03; I2 = 88%, moderate certainty of evidence), yet no differences in fasting insulin (MD: -1.59 pmol/L; 95% CI: -5.78, 2.59; I2 = 38%, moderate certainty of evidence), HOMA-IR (MD: -0.09; 95% CI: -0.35, 0.23; I2 = 60%, moderate certainty of evidence), HbA1c (MD: -0.14; 95% CI: -0.39, 0.10; I2 = 56%, very low certainty of evidence), or postprandial glucose response (SMD: -0.46; 95% CI: -1.28, 0.36; I2 = 74%, low certainty of evidence). Subgroup analyses revealed a beneficial effect for fasting blood glucose only among people with T2DM (low certainty of evidence). Our findings suggest a beneficial effect of reformulated breads high in dietary fiber, whole grains, and/or functional ingredients on fasting blood glucose concentrations in adults, primarily among those with T2DM. This trial was registered at PROSPERO as CRD42020205458.

Project description:BackgroundThe results of the studies that have investigated the effects of black tea on blood cholesterol are inconsistent. The aim of this study is to quantitatively assess the effects of black tea on cholesterol concentrations.MethodsPubMed, Embase, MEDLINE, and Cochrane Library (through to July 2014) were searched for randomized controlled trials (RCTs) designed to investigate the effect of black tea on blood cholesterol concentrations. The study quality was assessed by the Jadad scoring criteria. Pooled effect of black tea consumption on blood cholesterol concentrations was evaluated by fixed-effects or random-effects model. Meta-regression analyses were conducted to estimate dose effects of black tea polyphenols on concentrations of blood cholesterol. Subgroup and sensitivity analyses were performed to assess the potential source of heterogeneity.ResultsThe consumption of black tea did not significantly lower TC concentrations either in healthy subjects or patients with coronary artery diseases based on both fixed-effects and random-effects analysis. No significant change was observed in HDL-C concentrations in healthy participants or in subjects with coronary artery disease supplemented with black tea when compared with control participants. The pooled net change of LDL-C in healthy participants was -5.57 mg/dL (95% CI, -9.49 to -1.66 mg/dL; P = 0.005) in fixed-effects analysis and -4.56 (95% CI, -10.30 to 1.17 mg/dL; P = 0.12) in random-effects analysis. No significant net change was observed in LDL-C concentrations in patients with coronary artery disease. Subgroup and sensitivity did not significantly influence the overall outcomes of this meta-analysis. No significant dose effects of black tea polyphenols on blood cholesterol concentrations were detected in meta-regression analyses.ConclusionThe meta-analysis suggests that the consumption of black tea might not have beneficial effects on concentrations of TC, HDL-C, and LDL-C. Further high quality RCTs are needed to definitively draw a causal interpretation of the findings.

Dataset Information

Effects of green tea consumption on glycemic control: a systematic review and meta-analysis of randomized controlled trials.

Background

Methods

Results

Conclusions

Publications

Effects of green tea consumption on glycemic control: a systematic review and meta-analysis of randomized controlled trials.

Similar Datasets

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