Reduction of blood pressure with oral magnesium supplementation in women with mild to moderate hypertension

In a double-blind controlled trial, 91 middle-aged and elderly women with mild to moderate hypertension who were not on antihypertensive medication were randomly assigned to treatment with magnesium aspartate-HCl (20 mmol Mg/d) or placebo for 6 mo. Magnesium aspartate-HCl in the given dose was well-tolerated and was not associated with an increased frequency of diarrhea compared with placebo. At the end of the study, systolic blood pressure had fallen by 2.7 mm Hg (95% CI = 1.2, 6.7; P = 0.18) and diastolic blood pressure by 3.4 mm Hg (1.3, 5.6; P = 0.003) more in the magnesium group than in the placebo group. Blood pressure response was not associated with baseline magnesium status, as measured by dietary magnesium intake and urinary magnesium excretion. Urinary magnesium excretion in the magnesium group increased by 50% during the intervention period. No changes were seen in other biochemical indexes, including serum concentrations of total and high-density-lipoprotein cholesterol. The findings suggest that oral supplementation with magnesium aspartate-HCl may lower blood pressure in subjects with mild to moderate hypertension.