Daily Mg Supplements Above RDA Reduce High Blood Pressure in Hypertensive Human Subjects Not Taking Anti‐hypertensive Medications

Abstract

BACKGROUND: Studies of magnesium (Mg) therapy for hypertension have led to conflicting results; this study was an attempt to lend clarity to this seeming conflict.METHODS: Forty‐one human studies testing nutritional Mg supplements with “change in blood pressure” as a measured outcome were collected, sorted as to anti‐hypertensive medication status of subjects, and listed in order of ascending Mg dose.RESULTS: Daily Mg supplements of 20 mmol or 486 mg/day were necessary to significantly lower high blood pressure in subjects treatment‐naïve or taking anti‐hypertensive medications <6 months. This level is higher than the current adult RDAs for nutritional Mg (320 mg/day for women; 420 mg/day for men). Mg supplements as low as 10 mmol (230 mg) per day significantly lowered blood pressure of hypertensive subjects treated ≥6 months with anti‐hypertensive medications (diuretics, Ca channel blockers, ACE inhibitors, beta‐blockers). Magnesium supplements as high as 25 mmol/day (607 mg) did not significantly lower blood pressure in studies where ≥40% subjects were normotensive at baseline ‐‐ treated or untreated. Mg supplements as high as 40 mmol (972 mg)/day did not lower the blood pressure of subjects speculated to be Mg‐replete by their study's authors, showing the importance of a standard, clinical test for Mg status assessment for full knowledge to come from future studies of nutritional Mg.CONCLUSIONS: Mg daily dose of 20 mmol (1.1 – 1.5 times higher than RDAs) is necessary to significantly lower high blood pressure in human subjects either treatment‐naïve or on anti‐hypertensive medication <6 months. Subjects’ anti‐hypertensive medication usage ≥6 months (diuretics, beta‐blocker, Ca channel blocker, or ACE inhibitor) reduces by half the daily Mg dose necessary to lower blood pressure in Stage 1, uncomplicated hypertension.