Effects of Urtica dioica on Metabolic Profiles in Type 2 Diabetes: A Systematic Review and Meta-Analysis of Clinical Trials.

Background Several studies have investigated the effect of Urtica dioica (UD) consumption on metabolic profiles in patients with type 2 diabetes mellitus (T2DM); however, the findings are inconsistent. This systematic review and meta-analysis of clinical trials was performed to summarize the evidence of the effects of UD consumption on metabolic profiles in patients with T2DM. Methods Eligible studies were retrieved from searches of PubMed, Embase, Scopus, Web of Science, Cochrane Library and Google Scholar databases until December 2019. Cochran (Q) and I-square statistics were used to examine heterogeneity across included clinical trials. Data were pooled by using fixed-effect or random-effects model and expressed as weighted mean difference (WMD) and 95% confidence interval (CI). Results Among 1485 citations, thirteen clinical trials were found to be eligible for the current meta-analysis. UD consumption significantly decreased levels of fasting blood glucose (FBG) (WMD= -17.17 mg/dl, 95% CI: -26.60, -7.73, I2= 93.2%), hemoglobin A1c (HbA1c) (WMD= -0.93, 95% CI: -1.66, -0.17, I2= 75.0%), C-reactive protein (CRP) (WMD= -1.09 mg/dl, 95% CI: -1.64, -0.53, I2= 0.0%), triglycerides (WMD = -26.94 mg/dl, 95 % CI = [-52.07, -1.82], P = 0.03, I2 = 90.0%), systolic blood pressure (SBP) (WMD= -5.03 mmHg, 95% CI = -8.15, -1.91, I2= 0.0%) in comparison to the control groups. UD consumption did not significantly change serum levels of insulin (WMD= 1.07 μU/ml, 95% CI: -1.59, 3.73, I2= 63.5%), total-cholesterol (WMD= -6.39 mg/dl, 95% CI: -13.84, 1.05, I2= 0.0%), LDL-cholesterol (LDL-C) (WMD= -1.30 mg/dl, 95% CI: -9.95, 7.35, I2= 66.1%), HDL-cholesterol (HDL-C) (WMD= 6.95 mg/dl, 95% CI: -0.14, 14.03, I2= 95.4%), body max index (BMI) (WMD= -0.16 kg/m2, 95% CI: -1.77, 1.44, I2= 0.0%), and diastolic blood pressure (DBP) (WMD= -1.35 mmHg, 95% CI: -2.86, 0.17, I2= 0.0%) among patients with T2DM. Conclusion UD consumption may result in an improvement in levels of FBS, HbA1c, CRP, triglycerides and SBP, but did not affect on levels of insulin, total-, LDL-, and HDL-cholesterol, BMI, and DBP in patients with T2DM.