Oral magnesium supplements decrease high blood pressure (SBP>155 mmHg) in hypertensive subjects on anti-hypertensive medications: a targeted meta-analysis.
Study Goal
The researchers aimed to evaluate the effectiveness of oral magnesium supplementation in lowering blood pressure in hypertensive subjects on anti-hypertensive medication.
Results Summary
The meta-analysis of seven studies showed a significant reduction in both systolic and diastolic blood pressure with magnesium supplementation, with large effect sizes. Other studies with less stringent criteria showed mixed results, suggesting variability in response.
Population
Hypertensive subjects on anti-hypertensive medication for at least six months, with mean starting systolic blood pressure >155 mmHg.
Effective Dosage
Not specified
Duration
Not specified
Interactions
None mentioned
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
oral magnesium (Mg) supplementation | decrease | blood pressure | human studies | - | significant lowering | #1 |
oral magnesium (Mg) supplementation | no change | blood pressure | human studies | - | no effect | #2 |
Mg supplementation | decrease | systolic blood pressure (SBP) | 135 hypertensive subjects on anti-hypertensive medication continuously for at least six months, with no more than a two-week washout and with a mean starting systolic blood pressure (SBP)>155 mmHg | -18.7 mmHg [95% CI=-14.95 to -22.45] | demonstrated a mean change | #3 |
Mg supplementation | decrease | diastolic blood pressure (DBP) | 135 hypertensive subjects on anti-hypertensive medication continuously for at least six months, with no more than a two-week washout and with a mean starting systolic blood pressure (SBP)>155 mmHg | -10.9 mmHg [95% CI=-8.73 to -13.1] | showed a mean change | #4 |
oral Mg | decrease | both SBP and DBP | subjects approaching, but not meeting the >155 mmHg starting SBP values or not complying as regards anti-hypertensive medication usage | - | showed mean changes | #5 |
Mg treatment | decrease | hypertension | hypertensive subjects | - | showed a strong effect | #6 |
Previously, we examined 44 human studies involving oral magnesium (Mg) supplementation for hypertension (HT), sorting them according to HT status, Mg dose and anti-hypertensive medication usage. We found that while some studies reported a significant lowering of blood pressure with Mg supplementation, others did not. We present here our first meta-analysis of a uniform subset from this series of studies. Seven studies, involving 135 hypertensive subjects on anti-hypertensive medication continuously for at least six months, with no more than a two-week washout and with a mean starting systolic blood pressure (SBP)>155 mmHg, demonstrated a mean change of -18.7 mmHg [95% CI=-14.95 to -22.45] p<0.0001 and an effect size test (Cohen's d)=1.19, i.e. a large and highly significant effect. Meta-analysis of diastolic blood pressure (DBP) for these same seven studies showed a mean change in DBP of -10.9 mmHg [95% CI=-8.73 to -13.1], p<0.0001, with an effect size test (Cohen's d)=1.19. Other studies from our original collection, approaching, but not meeting the >155 mmHg starting SBP values or not complying as regards anti-hypertensive medication usage, showed mean changes in both SBP and DBP with oral Mg that, while not approaching the high-responder values of the present study, appeared to include some high-responder subjects combined with low- or non-responder subjects. This uniform subset of seven studies showed a strong effect of Mg treatment in hypertension, which is in stark contrast to results of three other meta-analyses. Using non-uniform sets of studies, the small effects reported in previous meta-analyses may reflect a blending of dissimilar studies, which acted to seriously underestimate the potential of Mg in hypertension in some (but not all) subjects. Within studies, blending of non-, moderate and highresponder subjects in any one study might mask strong effects of Mg treatment in some subjects.