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

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 dou-ble-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 resis-tance (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.