Oral Magnesium Supplementation for Treating Glucose Metabolism Parameters in People with or at Risk of Diabetes: A Systematic Review and Meta-Analysis of Double-Blind Randomized Controlled Trials

Nutrients
Q1
Nov 2021
Citations:41
Influential Citations:0
Systematic Reviews / Meta-Analyses
82
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Methods
Adults with diabetes (mostly type 2; some with type 1) or at high risk of diabetes; randomized, double-blind, placebo-controlled trials; parallel designs (majority) with some crossover designs; follow-up 4–48 weeks. Diabetic trials enrolled about 361 Mg vs 359 placebo; high-risk trials enrolled about 477 Mg vs 480 placebo. Mean ages: diabetics ~50.6 vs 49.9; high-risk ~42.5 vs 45.6; BMI ~28.8 vs 28.9; diabetics predominantly female; high-risk predominantly male.
Intervention
Oral magnesium supplementation; predominantly magnesium oxide; dosage not reported; duration 4–48 weeks (diabetes trials median ~12 weeks; high-risk trials median ~14 weeks); taken orally.
Results
In diabetes, magnesium supplementation significantly reduced fasting plasma glucose (11 studies; SMD −0.43; p=0.02); HbA1c and fasting insulin or HOMA-IR did not show significant improvements. In people at high risk of diabetes, magnesium significantly improved fasting plasma glucose (11 studies; SMD −0.34; p<0.0001), 2‑hour OGTT glucose (3 studies; SMD −0.35), and HOMA-IR (9 studies; SMD −0.23; p=0.028); HbA1c and serum insulin largely unchanged. Magnesium was generally well tolerated with gastrointestinal side effects (diarrhea) and no severe adverse events reported. Conclusion: Magnesium supplementation may improve glucose metabolism and insulin sensitivity in diabetes and those at high risk, though effects vary by outcome; larger, longer trials are needed to confirm and determine optimal dosing.
Limitations
Small-sample, short-duration RCTs with varied magnesium dosages and formulations leading to high heterogeneity; evidence mainly from type 2 diabetes; limited data on other diabetes types; inconsistent effects across outcomes (HbA1c and insulin); some crossover designs; follow-up durations varied.

Abstract

There is a large and growing body of literature focusing on the use of oral magnesium (Mg) supplementation for improving glucose metabolism in people with or at risk of diabetes. We therefore aimed to investigate the effect of oral Mg supplementation...