There are few developmental disorders more widely known than autism. Autism Spectrum Disorder (ASD) is a neurological condition generally associated with a set of symptoms including poor communication and repetitive behaviors. However, because autism is a spectrum disorder, it can be observed in varying levels of severity and there is no one way for an autistic person to act. It currently affects 1 in every 68 people worldwide and has increased proportionally with greater awareness to become the fastest-growing developmental disorder.
In light of the increasing prevalence of autism, several recent studies suggesting the neurological disorder may have its origins in the gut have gained large amounts of traction. This past July, The New York Times reported on the topic in an article titled “Children With Autism Carry Unique Gut Flora, Study Finds.” Much of the research is grounded in the idea that children with autism are unusually susceptible to gastrointestinal, or GI, disorders: up to 70% of children diagnosed with autism have impaired GI function in some way. Many studies cite the gut-brain axis as evidence of the potential of gut bacteria to influence neurological development. The gut-brain axis consists of the enteric nervous system (ENS) in our gut and central nervous system (CNS). The two are connected via a nerve called the vagus nerve and are integral to the functioning of the human brain.
The gut is far more important to brain health than one might assume. For example, the ENS produces around 90% of our neurotransmitters (signals that help regulate our emotions). Certain beneficial bacteria in the gut can help produce beneficial antioxidants and neuroprotective molecules. However, the presence of pathogenic bacteria in the gut can harm our brain health. The new theory connecting autism to poor gut health suggests that the presence of certain pathogenic bacteria in the gut can be an indicator of the disorder. The presence of the Clostridium strain of bacteria in the colon, for example, is correlated with a higher risk and severity of autism. Clostridium bacteria produce a neurotoxin associated with a range of behavioral problems.
Some studies suggest that using antibiotic medications excessively in the first two years of a child’s life increases their risk of developing ASD. Antibiotics are used to slow or stop the growth of pathogenic microbes, but they can also cause the gut to lose its diversity and change metabolic functions if used improperly. A child who faces repeated exposure to antibiotics in their first years may develop microbial dysbiosis, a disturbance to gut homeostasis, which could cause certain ASD genes to become activated. 34.5% of autistic children were given an unusually high number of antibiotic treatments in the first few years of their lives.
If ASD is truly a disorder of the gut, many methods used to fix microbial dysbiosis could also be beneficial in treating autism. But while new research on the connection between autism and gut health is exciting, it’s far from definitive. Because people with autism often have atypical dietary preferences, it’s not unlikely that abnormal gut bacteria in individuals with ASD is caused by diet rather than the source of the disorder itself. Furthermore, not all studies found relationships between gut bacteria and ASD–a study on 247 children with and without autism produced in Australia in 2021 found no significant correlations between ASD and gut bacteria. Finally, it’s important to proceed with caution when describing potential “cures” for autism. Because autism describes the way some individuals function rather than a life-threatening illness, many autistic people find the idea of a cure for their state of being offensive. Regardless of the implications on autism research, new studies on the connections between our gut and brain health are certainly interesting and have the potential to positively change the way we understand our health.
