Autism and the Gut Microbiome

Autism is a disorder that is characterized by issues with social skills and communication. There are many different manifestations of this disease and it is thought of as a spectrum. It can often be accompanied by anxiety, depression, sleep issues, and gastrointestinal issues.

It has been hypothesized that autism may have a link to the gut microbiome. Research in mice has shown that germ-free mice lacking the typical gut microbiome avoid other mice. This and other studies led to thinking that there was a potential role of the gut in influencing the brain. Towards this, other studies have shown that certain gut bacteria generate a small molecule (propionic acid) that disrupts the production of neurotransmitters. It has also been shown that individuals with autism have non-typical gut microbiota. A recent publication reviewed the literature, specifically nine studies that included 254 patients, in order to summarize the ways in which the gut microbiota of patients with autism differs from controls. This work ultimately identified a number of bacteria that were decreased either in abundance or percentage in patients with autism. These included Akkermansia, Bacteroides, Bifidobacterium, Parabacteroides, Enterococcus, and Escherichia coli. Their results underscored the potential of a gut-brain axis that has been previously proposed.

Clinical studies have been completed in children with autism where they take vancomycin to eliminate their existing gut bacteria followed by taking microbes from donors without autism. This improved gastrointestinal symptoms in the patients in this study for the two years that they were monitored. This provides hope that dietary intervention could be impactful in the treatment of patients with autism. Even so, there has not been research that supports that an imbalance in gut microbes causes autism. While a link has been determined, much remains to be studied.

Gut Microbes

Picture Source: neurosciencenews.com