Oral Magnesium Supplementation Reduces Ambulatory Blood Pressure in Patients With Mild Hypertension

BACKGROUND Accumulating evidence implicates a role of Mg2+ in the pathophysiology of essential hypertension. Previous studies evaluating the anti hypertensive efficacy of Mg2+ supplementation gave contradictory results. This study aimed to investigate the effect of oral Mg2+ supplementation on 24-h blood pressure (BP) and intracellular ion status in patients with mild hypertension. METHODS A total of 48 patients with mild uncomplicated hypertension participated in the study. Among them, 24 subjects were assigned to 600 mg of pidolate Mg2+ daily in addition to lifestyle recommendations for a 12-week period and another 24 age- and sex-matched controls were only given lifestyle recommendations. At baseline and study-end (12 weeks) ambulatory BP monitoring, determination of serum and intracellular ion levels, and 24-h urinary collections for determination of urinary Mg2+ were performed in all study subjects. RESULTS In the Mg2+ supplementation group, small but significant reductions in mean 24-h systolic and diastolic BP levels were observed, in contrast to control group (-5.6 +/- 2.7 vs. -1.3 +/- 2.4 mm Hg, P < 0.001 and -2.8 +/- 1.8 vs. -1 +/- 1.2 mm Hg, P = 0.002, respectively). These effects of Mg2+ supplementation were consistent in both daytime and night-time periods. Serum Mg2+ levels and urinary Mg2+ excretion were significantly increased in the intervention group. Intracellular Mg2+ and K+ levels were also increased, while intracellular Ca2+ and Na+ levels were decreased in the intervention group. None of the intracellular ions were significantly changed in the control group. CONCLUSION This study suggests that oral Mg2+ supplementation is associated with small but consistent ambulatory BP reduction in patients with mild hypertension.