Influence of magnesium status and magnesium intake on the blood glucose control in patients with type 2 diabetes.

Background & Aims: This study was undertaken to assess magnesium intake and magnesium status in patients with type 2 diabetes, and to identify the parameters that best predict alterations in fasting glucose and plasma magnesium.

Methods: A cross-sectional study was carried out in patients with type 2 diabetes (n = 51; 53.6 ± 10.5 y) selected within the inclusion factors, at the University Hospital Onofre Lopes. Magnesium intake was assessed by three 24-h recalls. Urine, plasma and erythrocytes magnesium, fasting and 2-h postprandial glucose, HbA1, microalbuminuria, proteinuria, and serum and urine creatinine were measured.

Results: Mean magnesium intake (9.37 ± 1.76 mmol/d), urine magnesium (2.80 ± 1.51 mmol/d), plasma magnesium (0.71 ± 0.08 mmol/L) and erythrocyte magnesium (1.92 ± 0.23 mmol/L) levels were low. Seventy-seven percent of participants presented one or more magnesium status parameters below the cut-off points of 3.00 mmol/L for urine, 0.75 mmol/L for plasma and 1.65 mmol/L for erythrocytes. Subjects presented poor blood glucose control with fasting glucose of 8.1 ± 3.7 mmol/L, 2-h postprandial glucose of 11.1 ± 5.1 mmol/L, and HbA1 of 11.4 ± 3.0%. The parameters that influenced fasting glucose were urine, plasma and dietary magnesium, while plasma magnesium was influenced by creatinine clearance.

Conclusions: Magnesium status was influenced by kidney depuration and was altered in patients with type 2 diabetes, and magnesium showed to play an important role in blood glucose control.