title: Effect of soy isoflavones on blood pressure: a meta-analysis of randomized controlled trials.
abstract: OBJECTIVE
  The effect of soy isoflavones on blood pressure is controversial. The objective of this study was to evaluate the effect of dietary soy isoflavones on blood pressure.
  
  
  RESULTS
  Trials were searched in PubMed, the Cochrane Library, Embase and references cited in related reviews and studies. A total of eleven trials were reviewed. Meta-analysis results showed a mean decrease of 2.5 mm Hg (95% CIs, - 5.35 to 0.34 mm Hg; P = 0.08) for systolic blood pressure and 1.5 mm Hg (95% CIs, - 3.09 to 0.17 mm Hg; P = 0.08) for diastolic blood pressure in the soy isoflavones-treated group compared to placebo. Meta-regression and subgroup analyses indicated that blood pressure status was a significant predictor of heterogeneity for the effect of soy isoflavones on blood pressure. Subgroup analysis of hypertensive subjects revealed that a greater blood pressure reduction was identified in the soy isoflavone-treated group compared to placebo (5 trials; SBP: - 5.94, 95% CIs [- 10.55, - 1.34] mm Hg, P = 0.01; DBP: - 3.35, 95% CIs [- 6.52, - 0.19] mm Hg, P = 0.04). In contrast, treatment with soy isoflavones did not lead to a significant reduction in blood pressure in normotensive subjects (6 trials; SBP: 0.29, 95% CIs [- 2.39, 2.97] mm Hg, P = 0.83; DBP: - 0.43, 95% CIs [- 1.66, 0.81] mm Hg, P = 0.50).
  
  
  CONCLUSIONS
  Soy isoflavones had an effect of lowering blood pressure in hypertensive subjects, but not in normotensive subjects. Larger trials need to be carried out to confirm the present findings.
authors.affiliation: The Key Laboratory of Clinical Cardiovascular Genetics, Ministry of Education and Sino-German Laboratory for Molecular Medicine, Beijing, PR China.
authors.forename: X X
authors.initials: XX
authors.lastname: Liu
authors.forename: S H
authors.initials: SH
authors.lastname: Li
authors.forename: J Z
authors.initials: JZ
authors.lastname: Chen
authors.forename: K
authors.initials: K
authors.lastname: Sun
authors.forename: X J
authors.initials: XJ
authors.lastname: Wang
authors.forename: X G
authors.initials: XG
authors.lastname: Wang
authors.forename: R T
authors.initials: RT
authors.lastname: Hui
mesh_terms: D001794:Blood Pressure / Q000187:drug effects*; D016208:Databases, Factual; D002149:Energy Intake; D006801:Humans; D007529:Isoflavones / Q000494:pharmacology*; D010936:Plant Extracts / Q000494:pharmacology*; D016032:Randomized Controlled Trials as Topic; D013025:Glycine max / Q000737:chemistry*
chemical_list: D007529:Isoflavones; D010936:Plant Extracts