The Effects of Magnesium Supplementation on Blood Pressure and Obesity Measure Among Type 2 Diabetes Patient: a Systematic Review and Meta-analysis of Randomized Controlled Trials

In this study, we aimed to systematically review the literature to evaluate the effects of magnesium (Mg) supplementation on blood pressure (BP) and obesity measure among patients with type 2 diabetes mellitus (T2DM). Major electronic databases of Web of Science, the Cochrane library, PubMed, and Scopus were searched completely from the inception until 15 October 2019 to identify randomized clinical trials (RCTs) pertaining to the topic of interest. All outcomes were pooled using a random-effects model and expressed as weighted mean differences (WMD) with 95% confidential intervals (CI). Heterogeneity, sensitivity analysis, and publication bias were also assessed using standard methods. The pooled analysis of five RCTs showed that Mg supplementation did not affect body weight (WMD: - 0.01 kg, 95% CI: - 0.36 to 0.33), BMI (WMD: - 0.07, 95% CI: - 0.18 to 0.04), and waist circumference (WMD: 0.12, 95% CI: - 1.24 to 1.48) in T2DM patients compared to the control groups of the patients who received placebo. However, pooling seven RCTs together showed significant reduction of systolic blood pressure (WMD: - 5.78 mmHg, 95% CI: - 11.37 to - 0.19) and diastolic blood pressure (WMD: - 2.50 mmHg, 95% CI: - 4.58 to - 0.41) in T2DM patients. Furthermore, subgroup analysis by dose of intervention, intervention duration, and type of intervention suggested that Mg supplementation for > 12 weeks, in doses higher than 300 mg/day or inorganic forms, could significantly decrease both systolic and diastolic BP in T2DM patients. Based on the findings, Mg supplementation has beneficial effects on BP in type 2 diabetes patients independent of body weight status. However, further investigations are needed to provide more reliable evidences.