Effect of ginger (Zingiber officinale) on blood glucose and lipid concentrations in diabetic and hyperlipidemic subjects: A meta-analysis of randomized controlled trials

Objective: The aim of our study was to assess the effect of ginger (Zingiber officinale) on blood glucose and lipid concentration in subjects with diabetes or hyperlipidemia. Methods: The literature search was conducted in PubMed and Scopus up to 30 October 2016. A total of nine randomized controlled trials were included in the meta-analysis. Weighted mean difference (WMD) and its 95% confidence interval were calculated for net changes in blood glucose (fasting blood-glucose [FBG]) and lipid concentrations (total cholesterol [TC], triglyceride [TG], low-density lipoprotein cholesterol [LDL-C], high density lipoprotein cholesterol [HDL-C]). Subgroup analyses were performed by clinical condition (hyperlipidemia and T2DM) and quality assessment (high and low quality). Results: Compared to the controls, ginger intake significantly reduced the concentrations of TG (WMD, -8.84; 95% CI: -11.95 to -5.73), TC (WMD, -4.42; 95% CI: -8.70 to -0.13), HDL-C (WMD, 2.87; 95% CI: 0.88-4.86) and FBG (WMD = -14.93; 95% CI: -19.83 to -10.04). Subgroup analyses by clinical condition of hyperlipidemia and high quality studies showed consistent results with the overall analysis, whereas, the subgroup analysis by clinical condition of diabetes showed a significant difference in the mean change of TG and FBG levels. Moreover, the high risk studies showed a significant change in the mean of FBG. Examining the funnel plot, suggests no publication bias. Conclusions: Ginger supplementation (tablet, capsules, powder or rhizomes) significantly reduced FBG, TG and TG and significantly increased HDL-C. But the changes were related to the clinical condition. More clinical trials evaluating the effects of ginger are warranted. (C) 2016 Elsevier Ltd. All rights reserved.