title: Homocysteine-lowering effect of 500 microg folic acid every other day versus 250 microg/day.
abstract: OBJECTIVE
  Elevated plasma total homocysteine (tHcy) concentrations are a risk factor for neural tube defects and vascular diseases. Supplementation with folic acid decreases tHcy. We investigated whether supplementation with 500 microg folic acid every other day is as effective in lowering tHcy as 250 microg folic acid each day.
  
  
  METHODS
  In a 4-week intervention study, 22 healthy young women (18-40 years old) took either 500 microg folic acid every other day (500-microg/2d group) or 250 microg folic acid each day (250-microg/d group). Fasting blood was collected on days 0 and 28.
  
  
  RESULTS
  Plasma folate concentrations increased by 11.4 nmol/l (6.8-15.9) in the 250-microg/d group and by 9.1 nmol/l (95% CI 1.9-16.3) in the 500-microg/2d group. These increases were not significantly different from each other. THcy concentrations decreased by 1.52 micromol/l (95% CI -2.09 to -0.95; p < 0.001) in the 250-microg/d group and by 0.88 micromol/l (-1.53 to -0.23; p < 0.05) in the 500-microg/2d group. The difference in decrease between the 250-microg/d group and the 500-microg/2d group was 0.64 micromol/l (p = 0.11).
  
  
  CONCLUSIONS
  Although not conclusive, this study suggests that supplying subjects with folic acid each day decreases tHcy more effectively than a double dose every other day.
authors.affiliation: Division of Human Nutrition and Epidemiology, Wageningen University, Wageningen, The Netherlands. ingeborg.brouwer@staff.NutEpi.wau.nl
authors.forename: I A
authors.initials: IA
authors.lastname: Brouwer
authors.forename: I A
authors.initials: IA
authors.lastname: van Rooij
authors.forename: M
authors.initials: M
authors.lastname: van Dusseldorp
authors.forename: C M
authors.initials: CM
authors.lastname: Thomas
authors.forename: H J
authors.initials: HJ
authors.lastname: Blom
authors.forename: J G
authors.initials: JG
authors.lastname: Hautvast
authors.forename: T K
authors.initials: TK
authors.lastname: Eskes
authors.forename: R P
authors.initials: RP
authors.lastname: Steegers-Theunissen
mesh_terms: D000293:Adolescent; D000328:Adult; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage* / Q000494:pharmacology; D006710:Homocysteine / Q000097:blood* / Q000187:drug effects; D006801:Humans; D009436:Neural Tube Defects / Q000517:prevention & control*; D013997:Time Factors
chemical_list: D006710:Homocysteine; D005492:Folic Acid