Effect of Zinc Supplementation on Lipid Profile and Body Composition in Patients with Type 2 Diabetes Mellitus: A GRADE-Assessed Systematic Review and Dose-Response Meta-analysis

The aim of this systematic review and meta-analysis of randomized controlled trials (RCTs) is to investigate the overall effects of zinc supplementation on lipid profile and body composition such as body weight (BW), body mass index (BMI), triglycerides (TG), total cholesterol (TC), low-density lipoprotein-cholesterol (LDL-C), and high-density lipoprotein-cholesterol (HDL-C) in patients with type 2 diabetes mellitus (T2DM). Scopus, Web of Science, PubMed, and Embase databases were searched from inception through October, 2023. The I² and Cochran’s Q tests were used to assess heterogeneity between studies. Nineteen RCTs (n = 1357 participants) were included in the meta-analysis. Zinc supplementation significantly reduced TG (WMD = − 17.41 mg/dL; 95% CI: − 22.60, − 12.22; P < 0.001), TC (WMD: − 19.60 mg/dL; 95% CI: − 28.46, − 10.73, P < 0.001), LDL-C (WMD = − 8.80 mg/dL; 95% CI: − 14.80, − 2.81; P = 0.004), and BMI (WMD = − 0.53 kg/m²; 95% CI: − 1.05, − 0.01; P = 0.046) but not BW (WMD: − 0.51 kg, 95 % CI: − 1.99, 0.97, P = 0.498). Moreover, zinc supplementation increased HDL-C (WMD = 4.82 mg/dL; 95% CI: 0.88, 8.76; P = 0.016) in patients with T2DM. Our results propose that zinc supplementation may be an effective strategy for improving lipid profile and body composition in patients with T2DM.