Examining the link between the microbiome, autism

A review paper published in Nutrition Reviews explores the current evidence base regarding the gut environment and nutritional status of children with autism spectrum disorder (ASD). Autism spectrum disorder is the fastest-growing neurodevelopmental disorder in the United States. Besides genetic risks, environmental factors have been suggested to contribute to the increase in ASD diagnosis over the past decade.

Several studies have reported abnormalities in microbiota composition and differences in microbial metabolites in children with ASD. Gastrointestinal discomfort is commonly reported in children with ASD, in addition to food selectivity and picky eating patterns. A number of mechanisms underlying the interaction between nutrition, the gut microbiota, and ASD symptoms via the microbiota–gut–brain axis have been proposed, including immune, hormonal, or neuronal pathways.

In their review, the researchers found accumulating evidence that demonstrates strong associations between the gut microbiota and ASD symptoms. Differences in microbiota composition are presented in the literature, but no clear trend is emerging yet, which may be attributable to differences in methodology, study population, and confounding factors, especially diet. Likewise, whether microbial dysbiosis contributes to the development of ASD symptoms or is caused by diet and medication remains unknown. Future studies investigating the microbiota in the context of dietary intake are needed to increase understanding of the interplay between diet and the gut microbiota in ASD and to identify potential dietary, probiotic, or prebiotic intervention strategies.

Review article