The correlation between dietary behaviors and gut microbiota in children with autism spectrum disorder: A cross‐sectional study

Objective This study investigated the associations between dietary behaviors and gut microbiota in children with autism spectrum disorder (ASD) stratified according to symptom severity, aiming to provide evidence for targeted interventions. Methods A cross‐sectional study enrolled 81 children with ASD aged 3–12 years, divided into mild‐to‐moderate ( n = 35) and severe ( n = 46) groups based on Childhood Autism Rating Scale scores. Dietary behaviors were assessed using the Children's Eating Behavior Questionnaire. Gut microbiota was analyzed by 16S rRNA (16S ribosomal RNA) gene sequencing. Spearman correlation examined associations. Results The severe ASD group showed significantly lower Enjoyment of Food scores and higher scores for both Emotional Undereating and Emotional Overeating ( p < 0.05). Alpha diversity (Shannon and Simpson indices) was significantly lower in the severe group ( p < 0.05). Beta diversity showed significant between‐group separation ( p < 0.05). The severe group exhibited decreased Firmicutes and increased Proteobacteria at the phylum level, with decreased Faecalibacterium and Dialister and a 2.8‐fold increase in Klebsiella at the genus level ( p < 0.05). Correlation analysis revealed severity‐dependent associations: mild‐to‐moderate ASD showed phylum‐level associations, while severe ASD showed genus‐level associations. Conclusion Children with severe ASD exhibited more pronounced dietary behavior abnormalities and gut microbiota dysbiosis. The severity‐dependent associations suggest stratified intervention strategies for ASD children.