Exploring the potential association between dietary factors and autism spectrum disorder: a Mendelian randomization analysis and retrospective study

Summary

This study combined two-sample Mendelian randomisation analysis of GWAS data with a small retrospective clinical trial to investigate causal relationships between dietary factors and autism spectrum disorder risk. Genetic analysis identified wholemeal pasta and cheese spread as increasing ASD risk, whilst banana showed a protective effect; mediation analysis suggested cheese spread effects partly operated through immune pathways. A gluten-free casein-free diet showed modest improvements in symptom scores and modulated specific immune markers compared to normal diet, though changes in standardised autism assessment scales were not statistically significant.

Regional applicability

Although the study uses international GWAS data, the specific causal estimates are population-derived and may not directly transfer to United Kingdom paediatric populations; the retrospective clinical component involved a small sample (n=78) and lacked randomisation, limiting clinical applicability. The immune-mediated mechanisms identified (HLA-DR+ T cells, EBV seropositivity) may be relevant to UK clinical practice if replicated in larger, controlled trials.

Key measures

Genome-wide association study data for 199 dietary factors; Childhood Autism Rating Scale (CARS); Autism Diagnostic Observation Schedule, Second Edition (ADOS-2); milk- and wheat-specific IgG levels; HLA-DR+ T cell CD45 levels; anti-Epstein–Barr virus IgG seropositivity

Outcomes reported

The study identified causal associations between specific dietary factors and ASD risk using genetic analysis, and evaluated clinical effects of a gluten-free casein-free diet on ASD symptoms in children aged 2–7 years measured by autism rating scales.

Topic tags