The effect of magnesium supplementation on blood pressure in individuals with insulin resistance, prediabetes, or noncommunicable chronic diseases: a meta-analysis of randomized controlled trials

Background: To our knowledge, the effect of magnesium supplementation on blood pressure (BP) in individuals with preclinical or noncommunicable diseases has not been previously investigated in a meta-analysis, and the findings from randomized controlled trials (RCTs) have been inconsistent. Objective: We sought to determine the pooled effect of magnesium supplementation on BP in participants with preclinical or noncommunicable diseases. Design: We identified RCTs that were published in English before May 2017 that examined the effect of magnesium supplementation on BP in individuals with preclinical or noncommunicable diseases through PubMed, ScienceDirect, Cochrane, clinicaltrials. gov, SpringerLink, and Google Scholar databases as well as the reference lists from identified relevant articles. Random-and fixed-effects models were used to estimate the pooled standardized mean differences (SMDs) with 95% CIs in changes in BP from baseline to the end of the trial in both systolic blood pressure (SBP) and diastolic blood pressure (DBP) between the magnesium-supplementation group and the control group. Results: Eleven RCTs that included 543 participants with follow-up periods that ranged from 1 to 6 mo (mean: 3.6 mo) were included in this meta-analysis. The dose of elemental magnesium that was used in the trials ranged from 365 to 450 mg/d. All studies reported BP at baseline and the end of the trial. The weighted overall effects indicated that the magnesium-supplementation group had a significantly greater reduction in both SBP (SMD: -0.20; 95% CI: -0.37, -0.03) and DBP (SMD: -0.27; 95% CI: -0.52, -0.03) than did the control group. Magnesium supplementation resulted in a mean reduction of 4.18 mm Hg in SBP and 2.27 mm Hg in DBP. Conclusion: The pooled results suggest that magnesium supplementation significantly lowers BP in individuals with insulin resistance, prediabetes, or other noncommunicable chronic diseases.