Oral Magnesium Supplementation Improves Insulin Sensitivity and Metabolic Control in Type 2 Diabetic Subjects

Abstract

OBJECTIVE—To determine whether oral magnesium supplementation (as magnesium chloride [MgCl2] solution) improves both insulin sensitivity and metabolic control in type 2 diabetic subjects with decreased serum magnesium levels. RESEARCH DESIGN AND METHODS—This study was a clinical randomized double-blind placebo-controlled trial. A total of 63 subjects with type 2 diabetes and decreased serum magnesium (serum magnesium levels ≤0.74 mmol/l) treated by glibenclamide received either 50 ml MgCl2 solution (containing 50 g MgCl2 per 1,000 ml solution) or placebo daily for 16 weeks. Chronic diarrhea, alcoholism, use of diuretic and/or calcium antagonist drugs, and reduced renal function were exclusion criteria. Homeostasis model assessment for insulin resistance (HOMA-IR) was used as the parameter of insulin sensitivity and glucose and HbA1c as parameters of metabolic control. RESULTS—At the end of the study, subjects who received magnesium supplementation showed significant higher serum magnesium concentration (0.74 ± 0.10 vs. 0.65 ± 0.07 mmol/l, P = 0.02) and lower HOMA-IR index (3.8 ± 1.1 vs. 5.0 ± 1.3, P = 0.005), fasting glucose levels (8.0 ± 2.4 vs. 10.3 ± 2.1 mmol/l, P = 0.01), and HbA1c (8.0 ± 2.4 vs. 10.1 ± 3.3%, P = 0.04) than control subjects. CONCLUSIONS—Oral supplementation with MgCl2 solution restores serum magnesium levels, improving insulin sensitivity and metabolic control in type 2 diabetic patients with decreased serum magnesium levels.