title: Long-term improvement in homocysteine levels and arterial endothelial function after 1-year folic acid supplementation.
abstract: OBJECTIVE
  Hyperhomocysteinemia, a risk factor for atherosclerosis, is associated with endothelial dysfunction that can be improved with short-term folic acid supplementation. The current study aimed to assess whether folic acid supplementation could produce longer-term improvements in homocysteine levels and arterial endothelial function.
  
  
  METHODS
  Twenty-nine healthy adults with hyperhomocysteinemia were selected from 89 volunteers enrolled in a community-based atherosclerosis screening project. All subjects were given folic acid (10 mg/d) for 1 year. Fasting plasma homocysteine levels were measured by high-performance liquid chromatography. Arterial endothelial function was measured as flow-mediated dilation of the brachial artery using high-resolution B-mode ultrasound.
  
  
  RESULTS
  Folic acid supplementation for 1 year was associated with a significant increase in mean (+/-SD) plasma folate levels (24 +/- 5 nmol/L to 40 +/- 5 nmol/L; P < 0.001) and a significant decline in homocysteine levels (9.0 +/- 1.7 micromol/L to 7.9 +/- 2.0 micromol/L; P < 0.001). Flow-mediated dilation also improved significantly, from 7.4% +/- 2.0% to 8.9% +/- 1.5% (P <0.0001), but there was no change in nitroglycerin-induced (endothelium-independent) responses.
  
  
  CONCLUSIONS
  These results demonstrate that long-term folic acid improves arterial endothelial function and has potential implications for the prevention of atherosclerosis in adults with hyperhomocysteinemia.
authors.affiliation: Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong.
authors.forename: Kam S
authors.initials: KS
authors.lastname: Woo
authors.forename: Ping
authors.initials: P
authors.lastname: Chook
authors.forename: Lindy L T
authors.initials: LL
authors.lastname: Chan
authors.forename: Alice S P
authors.initials: AS
authors.lastname: Cheung
authors.forename: Wing H
authors.initials: WH
authors.lastname: Fung
authors.forename: M u
authors.initials: Mu
authors.lastname: Qiao
authors.forename: Yvette I
authors.initials: YI
authors.lastname: Lolin
authors.forename: G N
authors.initials: GN
authors.lastname: Thomas
authors.forename: John E
authors.initials: JE
authors.lastname: Sanderson
authors.forename: Con
authors.initials: C
authors.lastname: Metreweli
authors.forename: David S
authors.initials: DS
authors.lastname: Celermajer
mesh_terms: D000328:Adult; D000368:Aged; D001161:Arteriosclerosis / Q000517:prevention & control*; D004730:Endothelium, Vascular / Q000000981:diagnostic imaging / Q000187:drug effects*; D005260:Female; D005492:Folic Acid / Q000097:blood / Q000627:therapeutic use*; D006801:Humans; D020138:Hyperhomocysteinemia / Q000188:drug therapy*; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D014463:Ultrasonography; D014664:Vasodilation / Q000187:drug effects
chemical_list: D005492:Folic Acid