The human gut harbors a complex community of microbes that profoundly influence many aspects of growth and development, including development of the nervous system. Advances in high-throughput DNA sequencing methods have led to rapidly expanding knowledge about this gut microbiome.

In this research study, we review fundamental emerging data on the human gut microbiome, with a focus on potential interactions between the microbiome and autism spectrum disorders (ASD) and consider research on atypical patterns of feeding and nutrition in ASD and how they might interact with the microbiome.

Although research is needed to elucidate the relationship between feeding problems, dietary patterns and gut dysbiosis in ASD, it seems plausible that interventions aimed at restoring the microbial balance in the gut may improve behaviors (e.g., irritability, anxiety, and social withdrawal) documented to occur more frequently among a subgroup of individuals with ASD and GI symptoms. Indeed, probiotics (i.e., microorganisms ingested through food or supplement consisting primarily of lactic acid-producing bacteria, such as lactobacilli, lactococci, bifidobacteria) have been shown to improve symptoms of irritable bowel syndrome, such as bloating, abdominal pain, and flatulence, and suggested as a possible intervention to improve behavioral issues associated with GI discomfort in ASD. It may also help explain anecdotal reports of improved functioning following dietary changes among certain children with ASD, which have helped propagate interest regarding the use of dietary manipulation (e.g., gluten and/or casein free, GFCF diet) in this population.

The Gut Microbiome: A New Frontier in Autism Research