A new study has attempted to shed light on the connection between gut imbalances in children with autism and the resulting changes in brain activity and behavior.
The University of Southern California (USC) study found that gut imbalances in children with autism may be driving an imbalance of metabolites in the digestive system. This imbalance appears to disrupt neurotransmitter production and impact behavior.
The connection between the gut and brain is not new. A study from 2024 found that bacteria in your digestive system might influence mental health, impacting issues like depression and anxiety. Another study from last year found that a high-fat diet can alter gut bacteria, driving changes that promote anxiety.
The latest findings, published on April 14 in Nature Communications, may provide insight into potential future treatments.
“We demonstrated that gut metabolites impact the brain, and the brain, in turn, affects behavior. Essentially, the brain acts as the intermediary between gut health and autism-related behaviors,” said one of the study’s authors, Lisa Aziz-Zadeh, a professor at the Brain and Creativity Institute at the USC Dornsife College of Letters, Arts and Sciences, per USC Today.
While Aziz-Zadeh says prior research has identified differences in the gut microbiomes and brain structure of people with autism, she says their latest study “connects the dots.”
Most communication between the two areas of the body is from the gut to the brain. In fact, 90% of the signals between the gut and brain start in the gut and travel to the brain. Only 10% of signals move in the opposite direction.
The idea of “feeling it in your gut” stems from the fact that we process many emotions via our stomach. It is a concept known as interoception, the ability to perceive and process signals from within the body.
The researchers examined behavioral data, brain imaging data, and stool samples from 84 children aged 8-17. Around half the children possessed an autism diagnosis, while the other half were neurotypical.
Metabolites produced by gut bacteria were examined in the participants’ stool and then correlated with brain differences and behavioral changes seen in children with autism. In particular, the researchers focused on the “tryptophan pathway” by which the amino acid tryptophan is processed into metabolites, including serotonin. Serotonin is essential for processing emotions, among other brain functions.
“We know that children with autism have brain differences — certain parts of their brain are either less active or more active compared to typically developing children,” said Aziz-Zadeh.
“We also know they often experience gastrointestinal issues, such as constipation, stomach pain and other digestive problems. Additionally, autism is associated with various symptoms, including repetitive behaviors and social difficulties.”
Sofronia Ringold, a doctoral student at the Brain and Creativity Institute, who helped with the study, says the findings may provide insight into future interventions that could target the gut and influence brain activity and ultimately, behavior. She also says the treatments could potentially simultaneously help relieve children with autism of the “symptoms that are the most uncomfortable for them.”