Hypomagnesemia in type II diabetes: effect of a 3-month replacement therapy

To investigate the effects of long-term high-dose oral magnesium (Mg) therapy (30 mmol/day) in patients with type II diabetes. Low plasma magnesium levels have been reported in type II diabetes and are associated with insulin resistance and diabetic late complications.

Forty patients with type II diabetes and hypomagnesemia were observed in a randomized double-blind placebo-controlled trial for 3 months (body mass index: 28 +/- 4 kg/m2; HbA1c: 7.4 +/- 0.8%). Plasma and urine magnesium and metabolic control parameters were determined, and side effects were considered, especially with regard to patients' compliance.

A significant increase in plasma magnesium levels was observed after 3 months of treatment (Mg: 0.73 +/- 0.8 vs. 0.81 +/- 0.1 mmol/l), reaching magnesium levels of the control group (0.88 +/- 0.8 mmol/l; NS); metabolic control, however, was not altered (HbA1c: 7.2 +/- 0.7 vs. 7.4 +/- 0.9%). Six months after the end of the trial, plasma magnesium declined to pretreatment levels (Mg: 0.73 +/- 0.07 mmol/l). The prevalence of side effects was high at the beginning and was reduced significantly during treatment.

We conclude that oral magnesium replacement therapy corrects hypomagnesemia after a minimum treatment period of 3 months. These observations might be important for the prevention of diabetic late complications.