title: Folate status of reproductive age women and neural tube defect risk: the effect of long-term folic acid supplementation at doses of 140 µg and 400 µg per day.
abstract: Primary prevention of most folate-responsive neural tube defects (NTDs) may not require 400 μg folic acid/day but may be achieved by attaining a high maternal folate status. Using RBC folate ≥906 nmol/L as a marker for NTD risk reduction, the study aimed to determine the change in blood folate concentrations in reproductive age women in response to long-term folic acid supplementation at 400 µg/day and 140 µg/day (dose designed to mimic the average daily folic acid intake received from New Zealand's proposed mandatory bread fortification program). Participants were randomly assigned to a daily folic acid supplement of 140 µg (n = 49), 400 µg (n = 48) or placebo (n = 47) for 40 weeks. RBC folate concentrations were measured at baseline, and after 6, 12, 29 and 40 weeks. At 40 weeks, the overall prevalence of having a RBC folate <906 nmol/L decreased to 18% and 35% in the 400 µg and 140 µg groups, respectively, while remaining relatively unchanged at 58% in the placebo group. After 40 weeks, there was no evidence of a difference in RBC folate between the two treatment groups (P = 0.340), nor was there evidence of a difference in the odds of a RBC folate <906 nmol/L (P = 0.078). In conclusion, the average daily intake of folic acid received from the proposed fortification program would increase RBC folate concentrations in reproductive age women to levels associated with a low risk of NTDs.
authors.affiliation: Department of Human Nutrition, University of Otago, Dunedin 9054, New Zealand.
authors.forename: Nicola A
authors.initials: NA
authors.lastname: Hursthouse
authors.affiliation: Department of Preventive and Social Medicine, University of Otago, Dunedin 9054, New Zealand.
authors.forename: Andrew R
authors.identifier: 0000-0003-4299-2194
authors.initials: AR
authors.lastname: Gray
authors.affiliation: Department of Human Nutrition, University of Otago, Dunedin 9054, New Zealand.
authors.forename: Jody C
authors.initials: JC
authors.lastname: Miller
authors.affiliation: Department of Human Nutrition, University of Otago, Dunedin 9054, New Zealand.
authors.forename: Meredith C
authors.initials: MC
authors.lastname: Rose
authors.affiliation: Department of Human Nutrition, University of Otago, Dunedin 9054, New Zealand.
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Houghton
mesh_terms: D000293:Adolescent; D000328:Adult; D001939:Bread; D019587:Dietary Supplements; D004311:Double-Blind Method; D004912:Erythrocytes / Q000737:chemistry; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage* / Q000097:blood; D005527:Food, Fortified; D006801:Humans; D009436:Neural Tube Defects / Q000517:prevention & control*; D009520:New Zealand; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D005492:Folic Acid