The effect of ginger supplementation on metabolic profiles in patients with type 2 diabetes mellitus: A systematic review and meta-analysis of randomized controlled trials

There is some evidence regarding the positive effects of ginger supplementation on metabolic profile in patients with type 2 diabetes (T2DM). However, they are conflicting. The present systematic review and meta-analysis aimed to summarize earlier findings for the effect of ginger supplementation on metabolic profile in patients with T2DM. Scopus, PubMed and Google Scholar databases were systematically searched up until September 2021 to collect all randomized clinical trials that evaluated the effect of ginger supplementation on FBS, HbA1c, TC, TG, LDL, HDL, SBP and DBP in patients with T2DM. We conducted our study according to the 2020 PRISMA guidelines. We included only English language publications. Pooled effect sizes were measured using a random-effects model and were reported as the weighted mean difference (WMD) and 95% CI. In addition, the Cochrane Collaboration's risk of bias tool was used to evaluate quality of the trials. In overall, 10 articles were included in this systematic review and meta-analysis. Our pooled meta-analysis indicated a significant reduction in FBS following ginger supplementation by polling 8 effect sizes [weighted mean difference (WMD): − 18.81; 95% CI: − 28.70, − 8.92), I2 = 77.4%] and in HbA1C through 7 effect sizes (WMD: −0.57; 95% CI: −0.93, −0.20, I2 =88.6%). Pooling 5 effect sizes, we found a significant reduction in SBP (WMD: −4.20; 95% CI: −7.64, −0.77, I2 =97%) and DBP [WMD: − 1.61; 95% CI: − 3.04, − 0.18), I2 = 93.2%] after supplementation with ginger. However, our pooled meta-analysis indicated that ginger supplementation had no significant influence on lipid profile involving TG, TC, LDL and HDL. We found significant reductions in FBS, HbA1C, SBP and DBP after supplementation with ginger in patients with T2DM compared to control group, with no significant changes in serum lipids. Further large RCTs are required to shed light on this issue.