title: The effect of soy or isoflavones on homocysteine levels: a meta-analysis of randomised controlled trials.
abstract: The present study aimed to evaluate the effect of soy or isoflavones on blood homocysteine levels via a systematic review and meta-analysis.
  
  
  
  Pubmed, Embase, Web of Science and the Cochrane Library (up to 16 December 2015) were used for the literature review. Only randomised controlled trials were included. The primary outcome was the standard mean difference (SMD) of blood homocysteine levels between the experimental and control groups.
  
  
  
  Nineteen randomised controlled studies were included for qualitative analysis. Eighteen studies were included in the data synthesis. Soy or isoflavones were found to have no effect on homocysteine levels, with a SMD of -0.21 (95% confidence interval = -0.43 to 0.00, I2=67.7%, random effect model). No publication bias was found among those studies (P = 0.296 for Egger's test, and P = 0.198 for Begg's test).
  
  
  
  Soy or isoflavones were not found to be associated with a reduction in homocysteine levels. Further studies might still be needed in carefully selected populations.
authors.affiliation: Department of Vascular Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China.
authors.forename: X
authors.initials: X
authors.lastname: Song
authors.affiliation: Department of Vascular Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China.
authors.forename: R
authors.initials: R
authors.lastname: Zeng
authors.affiliation: Department of Vascular Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China.
authors.forename: L
authors.initials: L
authors.lastname: Ni
authors.affiliation: Department of Vascular Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China.
authors.forename: C
authors.initials: C
authors.lastname: Liu
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D007529:Isoflavones / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D016032:Randomized Controlled Trials as Topic; D045730:Soy Foods / Q000009:adverse effects*; D055815:Young Adult
chemical_list: D007529:Isoflavones; D006710:Homocysteine
keywords: homocysteine; isoflavones; meta-analysis; soybean proteins