Kai Liu1, Rui Zhou, Bin Wang, Ka Chen, Lin-Ying Shi, Jun-Dong Zhu, Man-Tian Mi. 1. 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, People's Republic of China.
Abstract
BACKGROUND: The results of studies investigating the effect of green tea on glucose control and insulin sensitivity in humans are inconsistent. OBJECTIVE: We aimed to quantitatively evaluate the effect of green tea on glucose control and insulin sensitivity. DESIGN: We performed a strategic literature search of PubMed, EMBASE, and the Cochrane Library (updated to January 2013) for randomized controlled trials that evaluated the effects of green tea and green tea extract on glucose control and insulin sensitivity. Study quality was assessed by using the Jadad scale. Weighted mean differences were calculated for net changes in glycemic measures by using fixed-effects or random-effects models. We conducted prespecified subgroup and sensitivity analyses to explore potential heterogeneity. Meta-regression analyses were conducted to investigate dose effects of green tea on fasting glucose and insulin concentrations. RESULTS: Seventeen trials comprising a total of 1133 subjects were included in the current meta-analysis. Green tea consumption significantly reduced the fasting glucose and hemoglobin A1c (Hb A1c) concentrations by -0.09 mmol/L (95% CI: -0.15, -0.03 mmol/L; P < 0.01) and -0.30% (95% CI: -0.37, -0.22%; P < 0.01), respectively. Further stratified analyses from high Jadad score studies showed that green tea significantly reduced fasting insulin concentrations (-1.16 μIU/mL; 95% CI: -1.91, -0.40 μIU/mL; P = 0.03). CONCLUSIONS: This meta-analysis suggested that green tea had favorable effects, ie, decreased fasting glucose and Hb A1c concentrations. Subgroup analyses showed a significant reduction in fasting insulin concentrations in trials with high Jadad scores.
BACKGROUND: The results of studies investigating the effect of green tea on glucose control and insulin sensitivity in humans are inconsistent. OBJECTIVE: We aimed to quantitatively evaluate the effect of green tea on glucose control and insulin sensitivity. DESIGN: We performed a strategic literature search of PubMed, EMBASE, and the Cochrane Library (updated to January 2013) for randomized controlled trials that evaluated the effects of green tea and green tea extract on glucose control and insulin sensitivity. Study quality was assessed by using the Jadad scale. Weighted mean differences were calculated for net changes in glycemic measures by using fixed-effects or random-effects models. We conducted prespecified subgroup and sensitivity analyses to explore potential heterogeneity. Meta-regression analyses were conducted to investigate dose effects of green tea on fasting glucose and insulin concentrations. RESULTS: Seventeen trials comprising a total of 1133 subjects were included in the current meta-analysis. Green tea consumption significantly reduced the fasting glucose and hemoglobin A1c (Hb A1c) concentrations by -0.09 mmol/L (95% CI: -0.15, -0.03 mmol/L; P < 0.01) and -0.30% (95% CI: -0.37, -0.22%; P < 0.01), respectively. Further stratified analyses from high Jadad score studies showed that green tea significantly reduced fasting insulin concentrations (-1.16 μIU/mL; 95% CI: -1.91, -0.40 μIU/mL; P = 0.03). CONCLUSIONS: This meta-analysis suggested that green tea had favorable effects, ie, decreased fasting glucose and Hb A1c concentrations. Subgroup analyses showed a significant reduction in fasting insulin concentrations in trials with high Jadad scores.
Authors: Xiaochen Lin; Isabel Zhang; Alina Li; JoAnn E Manson; Howard D Sesso; Lu Wang; Simin Liu Journal: J Nutr Date: 2016-09-28 Impact factor: 4.798
Authors: Allison M Dostal; Hamed Samavat; Luis Espejo; Andrea Y Arikawa; Nicole R Stendell-Hollis; Mindy S Kurzer Journal: J Nutr Date: 2015-11-18 Impact factor: 4.798