Selective eating in autism linked to inflammatory gut bacteria

Eating behavior and early food patterns shape the gut bacteria in children with autism. Targeted diets and probiotics may help remodel the microbial communities associated with intestinal inflammation.

Study: Impact of eating behavior and dietary patterns on gut microbiota formation in children with autism spectrum disorders.. Image credit: Juria Mosin/Shutterstock.com

A recent study published in the journal Nutrients This suggests that there is an autism spectrum disorder. This is associated with altered gut microbiota composition in children, depending on their eating habits and food selectivity. The study also highlights the potential importance of personalized dietary interventions in altering gut microbiota composition and intestinal barrier markers.

Food selectivity shapes gut health in autism

Autism spectrum disorder (ASD) has become an extremely common neurodevelopmental disorder in children around the world. According to recent international surveillance data, it is estimated that every 31st child aged 4–8 years has ASD.

In addition to neuropsychiatric symptoms, children with ASD exhibit a number of physical conditions, including immune dysfunction, gastrointestinal complications, and eating disorders. These conditions may influence ASD pathogenesis and progression primarily through the gut microbiota-brain axis.

Existing evidence indicates that children with ASD often exhibit altered gut microbiota composition, which triggers systemic inflammation by activating immune cells. These cells can impair microglial activity and the integrity of the intestinal and blood-brain barriers, which are key hallmarks of ASD.

Gastrointestinal complications can also trigger sleep disturbances, irritability, and aggression, worsening the core symptoms of ASD. These symptoms may be misinterpreted by health professionals as core manifestations of the disorder rather than indicators of gastrointestinal discomfort, leading to a delay in diagnosis of true gastrointestinal pathology.

To avoid delayed diagnosis of physical health complications and consequent exacerbation of core ASD symptoms, substantial efforts have been made in recent times to investigate changes in gut microbiota composition, prevalence of concomitant pathologies, and their association with core symptoms of ASD.

The present study aimed to characterize the composition of the gut microbiota in relation to eating habits and nutritional intake. The effect of individual dietary intervention and short-term probiotic supplementation on gut microbiota composition and intestinal barrier markers was also examined.

Investigating microbiota changes following dietary interventions

The study included 96 children with ASD and 39 children without any neurodevelopmental or psychiatric disorders (control group).

Fecal samples from all participants were collected and analyzed for gut microbiota composition at baseline. Biomarkers of intestinal inflammation and barrier function were also evaluated. Information about eating habits and dietary patterns was collected through questionnaires.

Children with ASD were prescribed a rotational diet or elimination diet based on clinical testing, laboratory evaluation, and parent interview. An elimination diet is a diet plan that temporarily removes commonly associated foods, followed by systematically reintroducing them one by one. Rotational diet refers to eating a variety of foods over a set period of time rather than eating the same foods continuously.

Children followed these dietary interventions for 6 months and also consumed probiotic formulations for 1.5 months. At the end of the intervention period, 60 children with ASD who completed the follow-up assessment were assessed for all bowel-related parameters.

Selective eating linked to inflammatory gut bacteria

The study found significant changes in gut microbiota composition in children with ASD compared to their peers without the disorder. However, the study did not identify major differences in overall microbial diversity between the groups, despite significant differences in specific bacterial taxa.

Children with ASD who were breastfed showed increased abundance of certain bacteria that may potentially contribute to the pathogenesis of gastrointestinal and neuropsychiatric disorders. These children also showed reduced abundance of butyrate-producing bacteria, which are essential for maintaining intestinal barrier integrity, reducing inflammation, and improving metabolic health.

Characterization of the gut microbiota in formula-fed children with ASD demonstrated increased abundance of potentially unfavorable bacteria. Evidence has linked some of these bacteria to depressive disorders.

In addition to food type, eating habits significantly influence gut microbiota composition. Children with ASD who displayed selective eating behavior had higher levels of bacterial taxa associated with inflammatory activity, which may contribute to gastrointestinal disorders and neuropsychiatric symptoms.

Children with ASD who did not show selective eating habits also had higher levels of bacteria associated with inflammation compared to the control group. However, a comparison between children with ASD with and without selective eating patterns revealed increases in both inflammatory-associated and anti-inflammatory bacterial populations. The increase in anti-inflammatory bacteria may represent a compensatory response to increased inflammatory signaling.

Food selectivity, a common feature of eating disorders in children with ASD, is associated with inadequate intake of essential nutrients. Limiting food groups that support healthy gut microbiota, including fruits, vegetables and dietary fiber, may promote the growth of potentially harmful bacteria while reducing beneficial microbial populations.

Regarding dietary interventions, the study found that children with ASD who followed an elimination diet showed increased levels of beneficial short-chain fatty acid-producing bacteria.

The gut microbiota profiles of children with ASD who followed the rotational diet also showed mixed microbial changes, including potentially beneficial changes in some bacterial populations. However, an increase in bacterial taxa associated with inflammatory activity was observed regardless of dietary adherence.

Overall, these findings suggest that different types of dietary interventions are associated with multidirectional shifts in gut microbiota composition, affecting both potentially beneficial and potentially pathogenic bacterial populations. Further research in larger groups More randomized controlled trials are needed to better understand.

Of the children with ASD who participated in the study, 81 were boys, and 15 were girls. Although gender differences in gut microbiota only become significant during puberty, the researchers said that residual confounding resulting from the apparent gender imbalance between the groups cannot be completely ruled out.

The researchers also cautioned that the study had a non-randomized design and combined dietary intervention with probiotic supplementation, making it difficult to determine the individual contribution of each intervention to the changes observed in the microbiota.

Download your PDF copy by clicking here.