Magnesium reduces insulin-stimulated glucose uptake and serum lipid concentrations in type 1 diabetes.

A magnesium (Mg) deficit has been described in patients with type 1 diabetes, and it has been related to the development of cardiovascular disease. We tested the hypothesis that type 1 diabetic patients have deficits in dietary Mg intake and that proper long-term (24 weeks) oral Mg supplementation would reduce cardiovascular risk factors. Therefore, the Mg status, dietary Mg intake, and the effect of Mg supplementation were evaluated in 10 type 1 diabetic patients and 5 control subjects. Muscle Mg content was decreased by 7% in the type 1 diabetic patients, and it increased by 5% after 24 weeks of oral MgO supplementation. Acute and chronic Mg supplementation decreased serum total cholesterol, serum low-density lipoprotein (LDL)-cholesterol, and apolipoprotein B. Insulin-stimulated glucose uptake decreased by 35% after 24 weeks of oral MgO supplementation. Eight of 10 patients with type 1 diabetes had a daily intake of Mg below 90% of the recommended daily allowance. In conclusion, a Mg deficit was found in type 1 diabetic patients. The deficit might be due partly to a relatively Mg-deficient diet. Mg repletion was associated with a decrease in atherogenic lipid fractions and a reduced insulin-stimulated glucose uptake.