title: Maternal Folic Acid Supplementation during  Pregnancy and Childhood Allergic Disease  Outcomes: A Question of Timing?
abstract: Since the early 1990s, maternal folic acid supplementation has been recommended prior  to and during the first trimester of pregnancy, to reduce the risk of infant neural tube defects. In  addition, many countries have also implemented the folic acid fortification of staple foods, in order  to promote sufficient intakes amongst women of a childbearing age, based on concerns surrounding  variable dietary and supplementation practices. As many women continue to take folic acid  supplements beyond the recommended first trimester, there has been an overall increase in folate  intakes, particularly in countries with mandatory fortification. This has raised questions on the  consequences for the developing fetus, given that folic acid, a methyl donor, has the potential to  epigenetically modify gene expression. In animal studies, folic acid has been shown to promote an  allergic phenotype in the offspring, through changes in DNA methylation. Human population  studies  have  also  described  associations  between  folate  status  in  pregnancy  and  the  risk  of  subsequent childhood allergic disease. In this review, we address the question of whether ongoing  maternal folic acid supplementation after neural tube closure, could be contributing to the rise in  early life allergic diseases.
authors.affiliation: Department of Health Western Australia, Perth 6004, Western Australia, Australia. Catrina.Mcstay@health.wa.gov.au.
authors.forename: Catrina L
authors.initials: CL
authors.lastname: McStay
authors.affiliation: School of Paediatrics and Child Health, The University of Western Australia, Subiaco 6008, Western Australia, Australia. Carol.Bower@telethonkids.org.au.|Telethon Kids Institute, The University of Western Australia, Subiaco 6008, Western Australia, Australia. Carol.Bower@telethonkids.org.au.|Members of the in-FLAME International Inflammation Network, Perth 6000, Western Australia, Australia. Carol.Bower@telethonkids.org.au.
authors.forename: Susan L
authors.initials: SL
authors.lastname: Prescott
authors.affiliation: Telethon Kids Institute, The University of Western Australia, Subiaco 6008, Western Australia, Australia. Carol.Bower@telethonkids.org.au.
authors.forename: Carol
authors.initials: C
authors.lastname: Bower
authors.affiliation: School of Paediatrics and Child Health, The University of Western Australia, Subiaco 6008, Western Australia, Australia. debbie.palmer@uwa.edu.au.|Telethon Kids Institute, The University of Western Australia, Subiaco 6008, Western Australia, Australia. debbie.palmer@uwa.edu.au.|Members of the in-FLAME International Inflammation Network, Perth 6000, Western Australia, Australia. debbie.palmer@uwa.edu.au.
authors.forename: Debra J
authors.initials: DJ
authors.lastname: Palmer
mesh_terms: D000818:Animals; D002648:Child; D004032:Diet / Q000379:methods; D019587:Dietary Supplements / Q000009:adverse effects*; D005260:Female; D005492:Folic Acid / Q000009:adverse effects*; D005527:Food, Fortified / Q000009:adverse effects; D006801:Humans; D006967:Hypersensitivity / Q000209:etiology*; D039382:Maternal Nutritional Physiological Phenomena; D009436:Neural Tube Defects / Q000517:prevention & control; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D012307:Risk Factors; D013997:Time Factors
chemical_list: D005492:Folic Acid
keywords: allergic disease;  epigenetics;  folate;  folic acid;  maternal diet;  pregnancy