Andrea Rosanoff
Center for Magnesium Education & Research, LLC, Pahoa, HI, USA
Correspondence: A. Rosanoff, Ph.D., Director of Research, Center for Magnesium Education & Research, LLC, 13-1255
Malama St., Pahoa, HI 96778, USA
ARosanoff @ gmail.com

Magnesium supplements may enhance the effect of antihypertensive medications in stage 1 hypertensive subjects

Abstract:

Comprehensive analytical review of 44 human studies in 43 publications of oral Magnesium (Mg) therapy for hypertension (HT) shows Mg supplements may enhance the blood-pressure (BP) lowering effect of anti-hypertensive medications (medications) in Stage 1 HT subjects. 9 studies conducted on subjects treated with medications continuously ≥ 6 months (with ≤ 2-wk washout) resulted in significant decreases in both SBP and DBP with oral Mg supplements as low as 230 mg (10 mmol) per day. Twice this oral Mg dose, i.e. 460 mg/day, was required to significantly lower both SBP and DBP in 18 of 22 studies conducted on Stage 1 HT subjects either treatment-naïve or with their medication use interrupted ≥ 4 weeks within 6 months pre-study. Of the 4 remaining studies showing no BP change at these high Mg doses, two had large placebo effect, a third one had significant baseline discrepancies between Mg-test and placebo groups, and the fourth showed a significant decrease in DBP but not SBP. Thirteen studies on normotensive subjects, both treated and untreated with medications, showed no significant BP lowering effect with oral Mg therapy up to 25 mmol/day (607 mg). Conclusions: Mg supplements above RDA may be necessary to significantly lower high blood pressure in Stage I HT unless subjects have been continuously treated with anti-HT medications ≥ 6 months. Such medication use may lower by half the oral Mg dose needed to significantly decrease high blood pressure. Oral Mg therapy may have no effect in studies with normotensive subjects. Study of oral Mg therapy for severe or complicated hypertension has been neglected. Often the first cardiovascular risk factor to present, high blood pressure may be an early opportunity to correct poor Mg status and its possible complications including cardiovascular disease, respiratory diseases, and type 2 diabetes. Such preventive potential encourages quantification of these findings and testing of these hypotheses with a meta-analysis using categories elucidated by this preliminary study and finally would warrant a call for a prospective study.

Conclusion:

An inclusive, analytical review of 44 human studies from 43 publications shows that Mg supplements as low as 10 mmol (243 mg) per day may significantly lower blood pressure of stage 1, uncomplicated hypertensive subjects continuously treated 6 months or longer with anti-HT medications (including diuretics, beta-blockers, calcium channel blockers or ACE inhibitors). In contrast, daily Mg therapy at or above 20 mmol (486 mg) per day (i.e. above RDA), may be necessary to lower high blood pressure in studies on hypertensive subjects either treatment naïve or with at least a 4-week interruption in anti-HT medication use pre-study. Mg supplements as high as 25 mmol/day (607 mg) may not lower the blood pressure of treated or untreated normotensive subjects in blood pressure studies. Past noninclusive meta-analyses of these “Mg for hypertension” studies, along with the fact that the largest studies with Mg therapy for HT have been conducted on normotensive subjects, may have tended to minimize the potential of oral Mg therapy for HT. Given this minimized view of Mg’s potential, it is not surprising that studies of oral Mg therapy for severe (stage 2-3) hypertension were not found in the PubMed search. The findings of this analytical review suggest a categorized meta-analysis to test the following three hypotheses:

– stage 1 hypertension studies with subjects who are either treatment naïve or have their anti-HT medication use interrupted longer than 2 weeks
need oral Mg doses ≥ 20 mmol/day (above RDA values) to show significant blood pressure lowering results;

– stage 1 hypertension studies with subjects on 6 months’ uninterrupted anti-HT medications need only 10 mmol Mg/day (less than RDA values for
Mg) to significantly lower blood pressure;

– oral Mg therapy studies on subjects with prehypertension or normal blood pressure, whether “treated” or “untreated” with anti-HT medications, do not show a significant lowering of blood pressure with oral Mg therapy – even at Mg doses as high as 25 mmol/day.

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