title: Supplementation with a multivitamin containing 800 microg of folic acid shortens the time to reach the preventive red blood cell folate concentration in healthy women.
abstract: BACKGROUND
  The lowest risk of having a child with a neural tube defect (NTD) was related to red blood cell (RBC) folate concentrations of >906 nmol/L. For NTD prevention, it is recommended that women use periconceptional supplementation of 400 microg/day folic acid. Using this dose previous studies indicate that RBC folate >906 nmol/L was not reached within four weeks of supplementation.
  
  
  OBJECTIVE
  The effectiveness of a multivitamin/multimineral supplement containing 800 microg folic acid (verum) was evaluated using RBC folate concentration exceeding 906 nmol/L as primary endpoint. In addition, the time frame of achieving the threshold level was established as well as the effect of supplementation of other B vitamins on folate metabolism.
  
  
  METHODS
  46 healthy females received 800 microg/day of folic acid or placebo for 16 weeks. Blood samples were collected in four-week intervals. Plasma and RBC folate were measured with the microbiological method.
  
  
  RESULTS
  Mean (+/-SED) RBC folate increased over time to 1430+/-53 nmol/L, but did not reach a steady state after 16 weeks of intervention. Mean time to reach the target level was 4.2 +/- 3.5 weeks in the verum group. Intake of verum also led to an increase over time of plasma folate.
  
  
  CONCLUSIONS
  Preventive RBC folate concentration of more than 906 nmol/L can be reached within four weeks of supplementation with daily intake of 800 microg folic acid. With respect to NTD prevention, we suggest the re-evaluation of the current recommendation of folic acid supplementation.
authors.affiliation: Institute of Nutrition and Food Science, Human Nutrition II-Pathophysiology of Nutrition, University of Bonn, Endenicher Allee 11 - 13, D-53 115 Bonn, Germany.
authors.forename: Susanne
authors.initials: S
authors.lastname: Brämswig
authors.forename: Reinhild
authors.initials: R
authors.lastname: Prinz-Langenohl
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Lamers
authors.forename: Oliver
authors.initials: O
authors.lastname: Tobolski
authors.forename: Eva
authors.initials: E
authors.lastname: Wintergerst
authors.forename: Heiner K
authors.initials: HK
authors.lastname: Berthold
authors.forename: Klaus
authors.initials: K
authors.lastname: Pietrzik
mesh_terms: D000293:Adolescent; D000328:Adult; D004032:Diet; D015930:Diet Records; D019587:Dietary Supplements; D004311:Double-Blind Method; D004912:Erythrocytes / Q000737:chemistry*; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage* / Q000032:analysis / Q000097:blood; D006710:Homocysteine / Q000097:blood; D006801:Humans; D008715:Methionine; D018977:Micronutrients / Q000008:administration & dosage*; D009436:Neural Tube Defects / Q000517:prevention & control*; D009752:Nutritional Status; D012016:Reference Values; D012256:Riboflavin / Q000097:blood; D013997:Time Factors; D014805:Vitamin B 12 / Q000097:blood; D025101:Vitamin B 6 / Q000097:blood; D055815:Young Adult
chemical_list: D018977:Micronutrients; D006710:Homocysteine; D025101:Vitamin B 6; D005492:Folic Acid; D008715:Methionine; D014805:Vitamin B 12; D012256:Riboflavin