Magnesium citrate supplementation decreased blood pressure and HbA1c in normomagnesemic subjects with metabolic syndrome: a 12-week, placebo-controlled, double-blinded pilot trial.

Magnesium (Mg) supplementation was shown to improve metabolic syndrome (MetS) parameters in hypomagnesemic patients. The current study evaluated the role of Mg in normomagnesemic individuals with MetS. Patients were randomly assigned to 400 mg Mg as Mg citrate or placebo daily for 12 weeks. Blood pressure (BP), HbA1c, plasma concentrations of glucose, Mg and Ca, blood-ionized Mg, serum concentrations of cholesterol, triglycerides, vitamin D, creatinine, interleukin-6, and C-reactive protein were measured at baseline and after 12 weeks. Data were obtained from n = 13 in the Mg supplemented and n = 11 in the placebo group. Mg supplementation led to a significant increase in plasma Mg concentration (0.78 ± 0.07 mmol/L to 0.83 ± 0.07 mmol/L) and a decrease in systolic and diastolic BP (baseline: 145 ± 10/85 ± 3 mmHg; 12 weeks: 121 ± 5/79 ± 3 mmHg). HbA1c decreased significantly in the Mg group (6.43 ± 0.64% to 6.15 ± 0.55%), and the difference in change between placebo and Mg group was significant. Serum vitamin D levels significantly increased only in the Mg group. In normomagnesemic individuals with MetS, oral Mg citrate supplementation reduced HbA1c and BP.