Magnesium supplementation improves insulin sensitivity and blood glucose control, meta-analysis shows

Summary

This systematic review and meta-analysis was conducted to evaluate the effect of oral magnesium (Mg) supplementation on insulin sensitivity and glucose control in both diabetic and non-diabetic individuals.

The literature search included PubMed-Medline, SCOPUS, Web of Science and Google Scholar databases (from inception to November 25, 2015) to identify randomized, controlled trials of either parallel or cross-over design that evaluated the effect of Mg on insulin sensitivity and glucose control.

A total of 21 studies were included in the meta-analysis. The impact of Mg supplementation on plasma levels of glucose, glycated hemoglobin (HbA1c), insulin, and homeostasis model assessment-estimated insulin resistance (HOMA-IR) index was assessed. A random-effects model and generic inverse variance method were used to compensate for the heterogeneity of studies. Publication bias, sensitivity analysis, and meta-regression assessments were conducted using standard methods.

Results indicate Mg supplementation significantly reduced HOMA-IR index (Weighted Mean Difference [WMD]: -0.67, 95% CI: -1.20, -0.14, P=.013) but not plasma glucose (WMD: -0.20 mmol/L, 95% CI: -0.45, 0.05, P=.119), HbA1c (WMD: 0.018mmol/L, 95% CI: -0.10, 0.13, P=.756), or insulin (WMD: -2.22mmol/L, 95% CI: -9.62, 5.17, P=.556). A subgroup analysis found supplementing with Mg for at least 4 months significantly improved both HOMA-IR (P=.001) and fasting glucose levels (P<.001).

These findings indicate that Mg supplementation for at least 4 months significantly improves HOMA-IR index and fasting glucose in adults with or without diabetes, suggesting clinical value in patients with glucose metabolic disorders.