Folic acid and autism: updated evidences

ABSTRACT

Autism spectrum disorder (ASD) is a complex neurodevelopmental condition that impairs communication, socialization, and behavior. The association of ASD with folic acid has been investigated due to the importance of this vitamin for neurological health. This study is an update of the publication ‘Folic acid and autism: What do we know?’ and aims to systematically review studies examining the relationship between folic acid and ASD. The search resulted in 2,389 studies on folic acid and ASD, which were selected by two reviewers based on their titles and abstracts. Studies meeting the inclusion criteria were fully read. The 52 included studies involved 10,429 individuals diagnosed with ASD and assessed the intake of vitamin B6, folic acid, and vitamin B12; serum levels of these vitamins, homocysteine, and methionine; therapeutic interventions using folic acid; and the association between maternal exposure to this vitamin and the risk of ASD. The evidence of insufficient folic acid intake in most individuals with ASD remains consistent in this update. No association was found between maternal exposure to folic acid and the risk of ASD in their children. Despite observed improvements in communication, socialization, and behavior in individuals with ASD following folic acid interventions, it is crucial to consider the individuality and complexity of ASD. Given the relevance of the topic, there remains a need for more high-quality research and clinical trials characterized by rigorous methodological designs.

GRAPHICAL ABSTRACT

KEYWORDS:

• Autism spectrum disorder
• Autistic disorder
• folic acid
• vitamin B12
• vitamin B6
• vitamins
• child
• adolescent
• neurodevelopment

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This study was funded in part by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brasil (CAPES) – Financial Code 001, and supported by FIPE/HCPA, to whom we would like to express our gratitude.

Notes on contributors

Cristiane Vasconcelos

Cristiane Vasconcelos, MsC, nutritionist.

Ingrid Schweigert Perry

Ingrid Schweigert Perry, PhD, nutritionist.

Carmem Gottfried

Carmem Gottfried, PhD, professor at Universidade Federal do Rio Grande do Sul.

Rudimar Riesgo

Rudimar Riesgo, PhD, head of Neuropediatrics Department at Hospital de Clínicas de Porto Alegre.

Kamila Castro

Kamila Castro, PhD, nutritionist, researcher at Neuropediatrics Department at Hospital de Clínicas de Porto Alegre.