Table 4.
Effect magnesium on blood pressure or association with hypertension risk: A summary of meta-analyses of randomized controlled trials and observational studies.
| Author-Year | No. of Trials | Study Characteristics | No. Participants | Study Aims | Duration of Trials | Magnesium Dosage (Diet or Supplement) | Blood Pressure Lowering in mmHg or RR (95% CI) | Further Remarks/Summary |
|---|---|---|---|---|---|---|---|---|
| Zhang et al., 2016 [11] | 27 | Randomized controlled trials | Magnesium group: 822 Placebo group: 800 |
Effect of magnesium supplementation in normotensive and hypertensive adults (age 18–84 years). | 3 weeks–6 months | Median dose of 368 mg/day (range: 238–960 mg/day) | SBP: −2 (−0.4 to −3.6) DBP: −1.8 (−0.7 to –2.8) |
Magnesium supplementation at a median dose of 368 mg/day for a median duration of 3 months significantly reduced SBP and DBP. Magnesium supplementation at a dose of 300 mg/day or duration of 1 month is enough to elevate serum magnesium and reduce blood pressure. Serum magnesium was negatively associated with DBP but not SBP. |
| Dibaba et al., 2017 [48] | 11 | Randomized controlled trials | 543 | Assessing the pooled effect of magnesium supplementation on blood pressure in participants with preclinical or non−communicable diseases. | 1 to 6 months (mean: 3.6 months) | 365–450 mg/day | Standardized mean difference: SBP: −0.2 (−0.4 to −0.03) DBP: −0.3 (−0.5 to −0.03) |
Magnesium supplementation lowers blood pressure in individuals with insulin resistance, prediabetes, or other noncommunicable chronic diseases. |
| Verma and Garg 2017 [49] | 28 | Randomized controlled trials | 1694 (834 treatment arm, 860 placebo arm) | Evaluation the effect of magnesium supplementation on type 2 diabetes associated cardiovascular risk factors in both diabetic and nondiabetic individuals. Only four studies were carried out in hypertensive subjects. |
4−24 weeks | Elemental magnesium: 300–1006 mg/day | Weighted mean difference: SBP: −3.06 (−5.51 to −0.60) DBP: −1.37 (−3.02 to 0.29) |
A significant improvement was observed in SBP. Insignificant improvement or no improvement was observed in DBP |
| Kass et al., 2012 [50] | 22 | Interventional studies | 1173 | Assessing the effect of magnesium supplementation on blood pressure. Adults from 12 different countries were included. |
3 to 24 weeks of follow-up | Elemental magnesium dosage: 120–973 mg/day |
Overall effect size: SBP: 0.3 (0.2 to 0.4) DBP: 0.4 (0.3 to 0.4) |
Summary of all trials show a decrease in SBP of 3–4 mmHg and DBP of 2–3 mmHg. Magnesium supplementation appears to achieve a small but clinically significant reduction in blood pressure. |
| Rosanoff and Plesset 2013 [51] |
7 | Interventional studies | 135 treated hypertensive subjects | Evaluation of magnesium supplementation in hypertension. Initial SBP of the patients was >155 mmHg |
6 to 17 weeks | 10.5–18.5 mmol magnesium-salt/day | Mean change: SBP: −18.7 (−22.5 to −15.0) DBP: −10.9 (−13.1 to −8.7) |
This uniform subset of seven studies showed a strong effect of magnesium in treated hypertensive patients. |
| Observational studies | ||||||||
| Schoenaker et al., 2014 [45] | 3 | Observational studies | 6616 pregnant women, age range 20–40 years | Assessing the effect of dietary factors, including magnesium, on hypertensive disorders of pregnant women. | NA | Not indicated | Significantly lower mean magnesium intake of mean 7.69 mg/day for women with hypertensive disorders of pregnancy (gestational hypertension and pre-eclampsia) | Pooled results revealed statistically significantly lower mean magnesium intake for women with hypertensive disorders of pregnancy. |
| Han et al., 2017 [52] | 10 | Prospective cohort studies | 180,566 participates | Assessing the relationship between dietary magnesium intake and serum magnesium concentrations on the risk of hypertension in adults. Adult population >18 years was included. |
4–15 years | 96–425 mg/day | RR: 0.95 (0.90 to 1.00) for a 100 mg/increment in magnesium intake. Comparing highest to lowest: RR: 0.91 (0.80 to 1.02) |
Increase in magnesium intake was associated with a lower risk of hypertension in a linear dose-response pattern. |
| Wu J et al., 2017 [53] | 3 | Prospective cohort studies with four cohorts | 14,876 participants (3149 cases) | Evaluation of circulating magnesium levels and incidence of coronary heart diseases, hypertension, and type 2 diabetes mellitus | Average of 6.7 years of follow-up | NA | Per 0.1 mmol/L increment in serum magnesium levels: RR: 0.96 (0.93 to 0.99) |
A significant inverse linear association was observed between circulating magnesium levels and incidence of hypertension. |
SBP = Systolic blood pressure; DBP = Diastolic blood pressure; NA = not applicable.