New research from the Generation R study suggests that what mothers eat and what supplements they take during pregnancy could have lasting effects on children’s brain structure and behavior, offering some clues to reducing ADHD and autism traits.
Study: Prenatal Vitamin D, Multivitamin, and Folic Acid Supplementation and Brain Structure in Children with ADHD and ASD Traits: The Generation R Study. Image credit: Nemer-T/Shutterstock.com
Proper prenatal vitamin supplementation, especially folic acid, vitamin D, and multivitamins, could partially prevent neurodevelopmental outcomes in children. A recent study in Nutrients explores how vitamin supplementation in pregnancy and overall diet quality relate to brain structure and traits of autism spectrum disorder (ASD) and Attention-Deficit Hyperactivity Disorder (ADHD) in the offspring.
Introduction
The mother’s diet fundamentally affects brain development in the offspring. Folic acid and vitamin D supplements are central to neurodevelopment and may reduce the risk of anxiety and depression in the offspring.
Lower availability of vitamins in critical prenatal periods may increase the risk of ASD and ADHD. Earlier large cohort and meta-analysis studies reported a reduction in ASD risk of roughly 30-50% among children of mothers who took folic acid or multivitamin supplements. Similar findings have been reported in other cohorts, particularly among children with a high familial risk of ASD.
Still, evidence on how vitamin supplementation and overall diet are related to brain development, and how these factors may be linked to ASD or ADHD traits, remains limited. The current study’s authors investigated how maternal vitamin D, folic acid, multivitamin levels, and diet influence children’s brain structure, which could partly explain later behavioral traits.
About the study
The study included 3,937 children aged 9-11, from the Generation R cohort in Rotterdam, the Netherlands. Maternal dietary quality, vitamin D and folate serum levels, and supplement intake were assessed during pregnancy, along with a history of supplement intake.
The children were assessed by T1 structural magnetic resonance imaging (MRI) scans to measure cortical and subcortical brain volumes. Their parents filled out questionnaires to help identify ADHD traits at about age 9–10 and ASD traits at about age 13.
Study findings
Multivitamin supplementation was marginally associated with fewer ADHD traits in the offspring. Higher vitamin D levels during pregnancy were associated with children who later showed fewer ASD traits. At the same time, better dietary quality was associated with lower ADHD traits and, more modestly, lower ASD traits, respectively.
Vitamin D and better diet quality were associated with differences in brain volumes, but not always in the same direction: they were linked to larger temporal/parietal volumes and smaller frontal-temporal volumes, and higher diet quality was also linked to larger subcortical volumes.
These changes in temporal and parietal brain volumes were, in turn, associated with fewer traits of either ASD or ADHD. Children with increased subcortical volumes were more likely to have ASD/ADHD traits, however.
Mediation analyses showed that larger temporal and parietal brain volumes in the offspring were partly protective against the occurrence of ADHD, in response to changes in vitamin D levels, multivitamins, and overall dietary quality. With ASD traits, only multivitamin supplementation showed an indirect and minimal effect, partly via changes in frontal-temporal brain volumes, while no direct effect of multivitamins on ASD traits was found.
In this study, the differences were small in all cases. Still, they persisted despite adjusting for the effect of smoking or drinking during pregnancy and the mother’s socioeconomic and educational status. This underlines the importance of the mother’s diet in the offspring’s brain development.
The weak effects warrant further research to determine whether they provide valid evidence for preventive supplementation or dietary recommendations.
The lack of folate-associated effects could be because most women already had good folate supplementation. The authors note that folate levels may have reached a ceiling in this Dutch cohort, limiting detectable associations. Moreover, this observational design means the effects cannot be tracked based on the observed dietary intake or vitamin supplementation differences.
Conclusions
This large population-based study indicates that children whose mothers took multivitamin supplements in pregnancy had slightly lower ADHD scores. Again, mothers who took vitamin D had children with lower ASD scores. Higher dietary quality in pregnancy is associated with lower scores for both conditions.
Associations with brain volumes were mixed. Vitamin D, multivitamin use, and dietary quality are indirectly responsible for the decreased ADHD risk via the associated increase in temporal/parietal brain volume.
Multivitamin use affects ASD traits indirectly via frontal-temporal brain volume, but only minimally. Overall, these factors explained less than 2% of the variation in ASD and ADHD traits, underlining how limited the effects were.
However, the clinical relevance of these findings is doubtful and pending further research. Still, they agree with earlier studies and are biologically plausible. Future research should confirm these results in larger sample groups, focusing on how multivitamins and vitamin D protect against neurodevelopmental disorders.
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