Oral magnesium supplementation improves insulin sensitivity and metabolic control in type 2 diabetic subjects -: A randomized double-blind controlled trial

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 less than or equal to0.74 mmol/l) treated by glibenclamide received either 50 ml MgCl2 solution (containing 50 9 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 HbA(1c) 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 HbA(1c) (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.