title: The effect of magnesium supplementation on blood pressure: a meta-analysis of randomized clinical trials.
abstract: BACKGROUND
  An increased intake of magnesium might lower blood pressure (BP), yet evidence from clinical trials is inconsistent, perhaps as a result of small sample size or heterogeneity in study design.
  
  
  METHODS
  We performed a meta-analysis of randomized trials that tested the effects of magnesium supplementation on BP. Twenty trials meeting the inclusion criteria were identified. Random effects models and meta-regression methods were used to pool study results and to determine the dose-response relationship of magnesium to BP.
  
  
  RESULTS
  The 20 studies included 14 of hypertensive and 6 of normotensive persons totaling 1220 participants. The doses of magnesium ranged from 10 to 40 mmol/day (median, 15.4 mmol/day). Magnesium supplementation resulted in only a small overall reduction in BP. The pooled net estimates of BP change (95% confidence interval [CI]) were -0.6 (-2.2 to 1.0) mm Hg for systolic BP and -0.8 (-1.9 to 0.4) mm Hg for diastolic BP. However, there was an apparent dose-dependent effect of magnesium, with reductions of 4.3 mm Hg systolic BP (95% CI 6.3 to 2.2; P < .001) and of 2.3 mm Hg diastolic BP (95% CI 4.9 to 0.0; P = .09) for each 10 mmol/day increase in magnesium dose.
  
  
  CONCLUSIONS
  Our meta-analysis detected dose-dependent BP reductions from magnesium supplementation. However, adequately powered trials with sufficiently high doses of magnesium supplements need to be performed to confirm this relationship.
authors.affiliation: Department of Epidemiology and Disease Control, Yonsei University Graduate School of Health Science and Management, Seoul, Korea.
authors.forename: Sun Ha
authors.initials: SH
authors.lastname: Jee
authors.forename: Edgar R
authors.initials: ER
authors.lastname: Miller
authors.forename: Eliseo
authors.initials: E
authors.lastname: Guallar
authors.forename: Vikesh K
authors.initials: VK
authors.lastname: Singh
authors.forename: Lawrence J
authors.initials: LJ
authors.lastname: Appel
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Klag
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D001794:Blood Pressure / Q000187:drug effects*; D016001:Confidence Intervals; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D006973:Hypertension / Q000517:prevention & control*; D008274:Magnesium / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D016032:Randomized Controlled Trials as Topic
chemical_list: D008274:Magnesium