your comment about hba1c and heart disease made me decide to search for research on hba1c and magnesium. found this:
Diabetes. 1986 Apr;35(4):459-63.
Magnesium deficiency in IDDM related to level of glycosylated hemoglobin.
Magnesium and potassium were analyzed in plasma, erythrocytes, and urine collected during 24 h and in muscle biopsies from 25 subjects with insulin-dependent, type I diabetes mellitus (IDDM). Magnesium was also measured in mononuclear cells. The results were compared with those of 28 healthy controls, and were also correlated with the degree of diabetic control as estimated by analysis of the level of glycosylated hemoglobin (HbA1c). Subjects with IDDM had significantly lower muscle (P less than 0.01) and plasma (P less than 0.001) concentrations of magnesium compared with those of healthy controls. The HbA1c levels correlated significantly with the concentrations of magnesium in muscle (r = -0.62, P less than 0.001), plasma (r = -0.62, P less than 0.001), and mononuclear cells (r = -0.47, P less than 0.05). The results indicate that some patients with IDDM have lowered contents of magnesium in striated muscular and/or plasma, and that those parameters are dependent on the degree of diabetic control.
Clin Nutr. 2011 Jan 31. [Epub ahead of print]
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