Effects of zinc supplementation on lipid profile in patients with type 2 diabetes mellitus: A systematic review and meta-analysis of randomized controlled trials

Background and aim: Findings on the effects of zinc supplementation on the lipid profile in patients with type 2 diabetes mellitus (T2DM) are conflicting. The current comprehensive systematic review and meta-analysis aimed to summarize available evidence in this regard. Methods and results: After a systematic search in the online databases, we included the randomized controlled trials (RCTs) investigating the effect of zinc supplementation on lipid profile total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglyceride (TG) in patients with T2DM. Altogether, 9 studies with a total sample size of 424 patients with T2DM were included in the analysis. Combining 9 effect sizes from 9 RCTs, we found a significant lowering effect of zinc supplementation on serum levels of TG (weighted mean difference (WMD): �17.08, 95% CI: �30.59, �3.58 mg/dL, P = 0.01) and TC (WMD: �26.16, 95% CI: �49.69, �2.62 mg/dL, P = 0.02). Although the overall effect of zinc supplementation on LDL-C levels was not significant, a beneficial effect was seen in studies that administered <100 mg/d zinc. Based on the non-linear dose�response analysis, a greater reduction in serum levels of TC and LDL-C following zinc supplementation was seen at