title: Betaine supplementation decreases plasma homocysteine in healthy adult participants: a meta-analysis.
abstract: OBJECTIVE
  Betaine supplementation has been shown to be an effective agent for decreasing plasma homocysteine in healthy adults. Studies in healthy volunteers show that 6 g/d of betaine lowers plasma homocysteine concentrations by 5% to 20%. The purpose of this study was to perform a meta-analysis of randomized placebo-controlled trials that used daily betaine supplementation to identify the range in betaine's effects on lowering homocysteine.
  
  
  METHODS
  Five randomized controlled trials published between 2002 and 2010 were identified using MEDLINE and a manual search. All 5 studies used health adult participants who were supplemented with at least 4 g/d of betaine for between 6 and 24 weeks. A meta-analysis was carried out using a random-effects model, and the overall effect size was calculated for changes in plasma homocysteine.
  
  
  RESULTS
  The pooled estimate of effect for betaine supplementation on plasma homocysteine was a reduction of 1.23 μmol/L, which was statistically significant (95% confidence interval, - 1.61 to - 0.85; P = .01).
  
  
  CONCLUSIONS
  Supplementation with at least 4g/d of betaine for a minimum of 6 weeks can lower plasma homocysteine.
authors.affiliation: Associate Professor, Department of Basic Science, National University of Health Sciences, Lombard, IL.
authors.forename: Marc P
authors.initials: MP
authors.lastname: McRae
keywords: Betaine; Homocysteine; Meta-analysis