title: Folic acid and autism: What do we know?
abstract: Autism spectrum disorders (ASD) consist in a range of neurodevelopmental conditions that share common features with autism, such as impairments in communication and social interaction, repetitive behaviors, stereotypies, and a limited repertoire of interests and activities. Some studies have reported that folic acid supplementation could be associated with a higher incidence of autism, and therefore, we aimed to conduct a systematic review of studies involving relationships between this molecule and ASD. The MEDLINE database was searched for studies written in English which evaluated the relationship between autism and folate. The initial search yielded 60 potentially relevant articles, of which 11 met the inclusion criteria. The agreement between reviewers was κ = 0.808. The articles included in the present study addressed topics related to the prescription of vitamins, the association between folic acid intake/supplementation during pregnancy and the incidence of autism, food intake, and/or nutrient supplementation in children/adolescents with autism, the evaluation of serum nutrient levels, and nutritional interventions targeting ASD. Regarding our main issue, namely the effect of folic acid supplementation, especially in pregnancy, the few and contradictory studies present inconsistent conclusions. Epidemiological associations are not reproduced in most of the other types of studies. Although some studies have reported lower folate levels in patients with ASD, the effects of folate-enhancing interventions on the clinical symptoms have yet to be confirmed.
authors.affiliation: a Food and Nutrition Research Center (CESAN), Hospital de Clínicas de Porto Alegre , Porto Alegre , Brazil.|b Translational Research Group in Autism Spectrum Disorders (GETTEA) , Porto Alegre , Brazil.|c Instituto de Pesquisas, Ensino e Gestão em Saúde (iPGS) , Porto Alegre , Brazil.
authors.forename: Kamila
authors.initials: K
authors.lastname: Castro
authors.affiliation: a Food and Nutrition Research Center (CESAN), Hospital de Clínicas de Porto Alegre , Porto Alegre , Brazil.
authors.forename: Luciana da Silveira
authors.initials: Lda S
authors.lastname: Klein
authors.affiliation: b Translational Research Group in Autism Spectrum Disorders (GETTEA) , Porto Alegre , Brazil.|d Postgraduate Program in Child and Adolescent Health, Hospital de Clínicas de Porto Alegre , Porto Alegre , Brazil.
authors.forename: Diego
authors.initials: D
authors.lastname: Baronio
authors.affiliation: b Translational Research Group in Autism Spectrum Disorders (GETTEA) , Porto Alegre , Brazil.
authors.forename: Carmem
authors.initials: C
authors.lastname: Gottfried
authors.affiliation: b Translational Research Group in Autism Spectrum Disorders (GETTEA) , Porto Alegre , Brazil.|d Postgraduate Program in Child and Adolescent Health, Hospital de Clínicas de Porto Alegre , Porto Alegre , Brazil.|e Child Neurology Unit , Hospital de Clínicas de Porto Alegre , Porto Alegre , Brazil.
authors.forename: Rudimar
authors.initials: R
authors.lastname: Riesgo
authors.affiliation: a Food and Nutrition Research Center (CESAN), Hospital de Clínicas de Porto Alegre , Porto Alegre , Brazil.|f Academic Unit of Health Sciences, Universidade do Extremo Sul de Santa Catarina , Criciúma , Brazil.
authors.forename: Ingrid Schweigert
authors.initials: IS
authors.lastname: Perry
mesh_terms: D000293:Adolescent; D017195:Adolescent Nutritional Physiological Phenomena; D000067877:Autism Spectrum Disorder / Q000097:blood / Q000453:epidemiology / Q000209:etiology* / Q000517:prevention & control; D002648:Child; D002664:Child Nutritional Physiological Phenomena; D004032:Diet / Q000009:adverse effects; D019587:Dietary Supplements / Q000009:adverse effects*; D019317:Evidence-Based Medicine; D005260:Female; D047109:Fetal Development; D005492:Folic Acid / Q000009:adverse effects* / Q000097:blood / Q000627:therapeutic use; D005494:Folic Acid Deficiency / Q000097:blood / Q000178:diet therapy / Q000503:physiopathology / Q000517:prevention & control; D006710:Homocysteine / Q000097:blood; D006801:Humans; D020138:Hyperhomocysteinemia / Q000097:blood / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control; D015994:Incidence; D008297:Male; D039382:Maternal Nutritional Physiological Phenomena; D011247:Pregnancy; D015203:Reproducibility of Results; D012307:Risk Factors
chemical_list: D006710:Homocysteine; D005492:Folic Acid
keywords: Autistic disorder; Folic acid; Vitamins