Dietary Patterns, Not Gut Microbiome Composition, Are Associated with Behavioral Challenges in Children with Autism: An Observational Study.

This study looked at gut bacteria and eating habits in 17 children with autism compared to their siblings and parents. The researchers found no differences in gut bacteria between the groups. However, children with autism ate more sweets and sugary foods, fewer vegetables, and had less variety in their diet overall. The study suggests that picky eating behaviors common in autism affect diet, which then impacts gut bacteria - not the other way around.

This observational study compared gut microbiome composition and dietary patterns in children with autism (n=17), their non-autistic siblings (n=9), and parents (n=27). Researchers found no significant differences in bacterial or fungal gut microbiome diversity between groups. However, children with autism showed distinct dietary patterns: higher consumption of sweets and sugary foods, lower vegetable intake, and reduced overall dietary diversity. Statistical analyses confirmed that dietary factors, rather than microbiome composition, explained differences between autism and non-autism groups.

The findings suggest that selective eating behaviors characteristic of autism shape dietary intake, which subsequently influences gut microbial diversity, indicating a behavior-to-diet-to-microbiome pathway rather than microbiome-to-behavior.

Results suggest nutritional interventions targeting selective eating behaviors may be more effective than microbiome-focused treatments. Clinicians should prioritize dietary diversity and nutrition education. The findings support addressing food selectivity as a primary intervention target to improve overall health outcomes in children with autism.

Small sample size (17 children with autism) limits generalizability. Observational design cannot establish causality. Single time-point assessment may not capture temporal variations. Family-based comparison may introduce genetic confounding factors that could influence both dietary preferences and microbiome composition.

: Autism Spectrum Disorder (ASD) is a complex neurodevelopmental condition characterized by persistent social communication difficulties and restricted, repetitive behaviors, with prevalence estimates continuing to rise worldwide. The gut-brain axis has been proposed as a potential contributor to ASD, yet human studies yield inconsistent findings, partly due to confounding effects of diet and behavior.: Here, we investigated the gut bacteriome and mycobiome of children with ASD (= 17) compared with their non-ASD siblings (= 9) and parents without ASD (= 27), alongside detailed assessment of dietary intake (= 79) using 7-day food diaries.: Multi-kingdom microbiome profiling revealed no significant differences in α- or β- diversity across ASD, sibling, and parental groups, with only minor taxonomic variation observed. Similarly, fungal community composition showed negligible group-level differences. By contrast, dietary patterns strongly differentiated ASD from non-ASD participants: children with ASD consumed higher levels of sweets and sugary foods, lower portions of vegetables, and exhibited reduced overall dietary diversity.

Statistical analyses confirmed that dietary factors, rather than microbial composition, explained variation in ASD diagnosis.: These findings suggest that selective and repetitive eating behaviors are characteristic of ASD shape dietary intake, which in turn influences gut microbial diversity. Thus, in humans, the directionality may run primarily from behavior to diet to microbiome, rather than from microbiome to behavior. Our results underscore the importance of incorporating dietary variables into microbiome research and highlight the need for targeted nutritional interventions to improve health outcomes in individuals with ASD.