title: Assessing the association between natural food folate intake and blood folate concentrations: a systematic review and Bayesian meta-analysis of trials and observational studies.
abstract: Folate is found naturally in foods or as synthetic folic acid in dietary supplements and fortified foods. Adequate periconceptional folic acid intake can prevent neural tube defects. Folate intake impacts blood folate concentration; however, the dose-response between natural food folate and blood folate concentrations has not been well described. We estimated this association among healthy females. A systematic literature review identified studies (1 1992-3 2014) with both natural food folate intake alone and blood folate concentration among females aged 12-49 years. Bayesian methods were used to estimate regression model parameters describing the association between natural food folate intake and subsequent blood folate concentration. Seven controlled trials and 29 observational studies met the inclusion criteria. For the six studies using microbiologic assay (MA) included in the meta-analysis, we estimate that a 6% (95% Credible Interval (CrI): 4%, 9%) increase in red blood cell (RBC) folate concentration and a 7% (95% CrI: 1%, 12%) increase in serum/plasma folate concentration can occur for every 10% increase in natural food folate intake. Using modeled results, we estimate that a natural food folate intake of ≥ 450 μg dietary folate equivalents (DFE)/day could achieve the lower bound of an RBC folate concentration (~ 1050 nmol/L) associated with the lowest risk of a neural tube defect. Natural food folate intake affects blood folate concentration and adequate intakes could help women achieve a RBC folate concentration associated with a risk of 6 neural tube defects/10,000 live births.
authors: Oak Ridge Institute for Science and Education (ORISE), Oak Ridge, TN 37831, USA. claire.marchetta@gmail.com.
authors: Claire M
authors: CM
authors: Marchetta
authors: Carter Consulting, Inc., Atlanta, GA 30345, USA. ojd1@cdc.gov.
authors: Owen J
authors: OJ
authors: Devine
authors: Division of Birth Defects and Developmental Disabilities (DBDDD), National Center on Birth Defects and Developmental Disabilities (NCBDDD), Centers for Disease Control and Prevention, Atlanta, GA 30329, USA. kvc3@cdc.gov.
authors: Krista S
authors: KS
authors: Crider
authors: Oak Ridge Institute for Science and Education (ORISE), Oak Ridge, TN 37831, USA. bltsang@gmail.com.
authors: Becky L
authors: BL
authors: Tsang
authors: Division of Birth Defects and Developmental Disabilities (DBDDD), National Center on Birth Defects and Developmental Disabilities (NCBDDD), Centers for Disease Control and Prevention, Atlanta, GA 30329, USA. iqt8@cdc.gov.
authors: Amy M
authors: AM
authors: Cordero
authors: Oak Ridge Institute for Science and Education (ORISE), Oak Ridge, TN 37831, USA. rv7@cdc.gov.
authors: Yan Ping
authors: YP
authors: Qi
authors: Acentia, Falls Church, VA 22042, USA. shashagj@gmail.com.
authors: Jing
authors: J
authors: Guo
authors: Division of Birth Defects and Developmental Disabilities (DBDDD), National Center on Birth Defects and Developmental Disabilities (NCBDDD), Centers for Disease Control and Prevention, Atlanta, GA 30329, USA. rjb1@cdc.gov.
authors: Robert J
authors: RJ
authors: Berry
authors: Division of Birth Defects and Developmental Disabilities (DBDDD), National Center on Birth Defects and Developmental Disabilities (NCBDDD), Centers for Disease Control and Prevention, Atlanta, GA 30329, USA. jyr4@cdc.gov.
authors: Jorge
authors: J
authors: Rosenthal
authors: Carter Consulting, Inc., Atlanta, GA 30345, USA. jxm1@cdc.gov.
authors: Joseph
authors: J
authors: Mulinare
authors: SciMetrika, LLC, Atlanta, GA 30329, USA. pmersereau@comcast.net.
authors: Patricia
authors: P
authors: Mersereau
authors: Division of Nutrition, Physical Activity, and Obesity (DNPAO), National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP), Centers for Disease Control and Prevention, Atlanta, GA 30329, USA. hfc2@cdc.gov.
authors: Heather C
authors: HC
authors: Hamner
mesh_terms: D000293:Adolescent; D000328:Adult; D001499:Bayes Theorem; D002648:Child; D016208:Databases, Factual; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage* / Q000097:blood*; D006801:Humans; D008875:Middle Aged; D009436:Neural Tube Defects / Q000517:prevention & control; D015596:Nutrition Assessment; D009751:Nutritional Requirements; D064887:Observational Studies as Topic; D016032:Randomized Controlled Trials as Topic; D055815:Young Adult
chemical_list: D005492:Folic Acid