title: Effect of riboflavin supplementation on plasma homocysteine in elderly people with low riboflavin status.
abstract: OBJECTIVE
  To investigate the effect of riboflavin supplementation on plasma homocysteine (tHcy) concentrations in healthy elderly people with sub-optimal riboflavin status.
  
  
  METHODS
  A double-blind, randomized, placebo-controlled riboflavin supplementation trial.
  
  
  METHODS
  Community based study in Northern Ireland.
  
  
  METHODS
  From a screening sample of 101 healthy elderly people, 52 had sub-optimal riboflavin status (erythrocyte glutathione reductase activation coefficient, EGRAC>or=1.20) and were invited to participate in the study.
  
  
  METHODS
  The intervention had two parts. Part 1 was a 12 week randomized double blind, placebo-controlled intervention with riboflavin (1.6 mg/day). Following completion of part 1, the placebo group went on to part 2 of the study which involved supplementation with folic acid (400 micro g/day) for 6 weeks followed by folic acid and riboflavin (1.6 mg/day) for a further 12 weeks, with a 16 week washout period post-supplementation. The purpose of part 2 was: (a) to address the possibility that homocysteine-lowering in response to riboflavin may be obscured by a much greater effect of folate, and that, once folate status was optimized, a dependence of homocysteine on riboflavin might emerge; and (b) to demonstrate that these subjects had homocysteine concentrations which could be lowered by nutritional intervention.
  
  
  RESULTS
  Although riboflavin supplementation significantly improved riboflavin status in both parts 1 and 2 of the study (P<0.001 for each), tHcy concentrations were unaffected (P=0.719). In contrast, folic acid supplementation (study part 2) resulted in a homocysteine lowering of 19.6% (P=0.001).
  
  
  CONCLUSIONS
  Despite the metabolic dependency of tHcy on riboflavin, it did not prove to be an effective homocysteine-lowering agent, even in the face of sub-optimal riboflavin status.
authors.affiliation: Northern Ireland Centre for Food and Health (NICHE), University of Ulster, Coleraine, Northern Ireland.
authors.forename: M C
authors.initials: MC
authors.lastname: McKinley
authors.forename: H
authors.initials: H
authors.lastname: McNulty
authors.forename: J
authors.initials: J
authors.lastname: McPartlin
authors.forename: J J
authors.initials: JJ
authors.lastname: Strain
authors.forename: J M
authors.initials: JM
authors.lastname: Scott
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D019587:Dietary Supplements; D004311:Double-Blind Method; D005260:Female; D005492:Folic Acid / Q000097:blood; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D008297:Male; D009660:Northern Ireland; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D012256:Riboflavin / Q000627:therapeutic use*; D012257:Riboflavin Deficiency / Q000178:diet therapy*; D014805:Vitamin B 12 / Q000097:blood
chemical_list: D017319:Photosensitizing Agents; D006710:Homocysteine; D005492:Folic Acid; D014805:Vitamin B 12; D012256:Riboflavin