The Relationship Between Food Selectivity, Gastrointestinal Dysfunction and Biomarkers in Autism Spectrum Disorder

Background: Autism spectrum disorder (ASD) is a clinically heterogeneous, multi-system disorder with a variety of comorbidities, commonly including eating and feeding problems, with many children on the autistic spectrum suffering from some manifestation of food selectivity or picky eating. Though these problems are typically addressed through behavior-based, therapeutic approaches, increasing evidence shows they may be organic in nature, and linked with underlying gastrointestinal dysfunction (GID) and other biochemical imbalances such as immune dysregulation, inflammation, impaired detoxification, oxidative stress, mitochondrial disease/dysfunction and more. While eating problems in ASD are thought to cause health problems and can even, at times, be life threatening, it has not yet been investigated whether food selectivity is related to specific biomarkers appearing in early childhood, nor has the connection between food selectivity and GI function been explored. 

Objectives: The aims of the study were to: (1) identify & characterize urine-based biomarkers of children with ASD (2) identify whether specific biomarkers and GI problems in children with ASD are correlated with food selectivity. 

 Methods: An anonymous review of the clinical charts of 68 children with a diagnosis of ASD, was performed. Participant ages ranged from 3-7 years.  Descriptive statistics were used to illustrate the percentage of participants whose results were above the normal range for each metabolite. Metabolites for which greater than 25% of the children had elevated levels are reported in this study. Chi square test was used to assess the correlations between parental report of food selectivity and elevated metabolites as well as parental report of GI symptoms and elevated metabolites.

Results: All 68 children had at least one elevated organic acid metabolite, and the mean number of elevated metabolites was 9.5 (SD = 5). Of the 53 metabolites assessed, 15 metabolites were elevated in 25% or more of the population studied and 20 metabolites were elevated in between 10-24% of the population. The rest of the metabolites were elevated in under 10% of the population. Parents of 60% of children reported food selectivity. 47% of parents who reported food selectivity also reported GI symptoms in their children. Food selectivity was found to be correlated with elevated Vanillylmandelic acid (VMA) (28.1% elevated; ²χ)₍₁₎=4.24, P=0.4)), Suberic acid (26.9% elevated; 2χ)(1)=4.89, P=0.3)), 3-oxoglutaric acid (43.5% elevated; 2χ(1)=3.59, P=0.6), Arabinose (80.9% elevated; 2χ)(1)=3.73, P=0.05), and Oxalates (43.3% elevated; (2χ)(1)=3.77, P=0.5).  

Conclusions: This study highlights the relationship between food selectivity, GID and select organic acid metabolites, raising the possibility that food selectivity, at least among certain cases of ASD, may be the result of unbalanced gut bacteria, and associated symptoms.  Future studies should explore whether the presence of elevated biological metabolites related to GI health may be able to predict food selectivity.