The gut and brain are connected through the gut-brain axis, which influences behavior, brain development and emotions.
Early gut microbiome disruptions (e.g., antibiotic overuse, C-section birth) may contribute to ASD risk.
Gut microbiome-based therapies, including FMT, probiotics and targeted bacterial treatments, show promise as ASD treatments.
More research is needed to develop safe and effective gut microbiome interventions.
For years, autism spectrum disorder (ASD) has remained a complex neurological condition, puzzling researchers and families alike. But an emerging field of science is shedding light on a surprising connection: the gut microbiome.
In a study published in the journal Frontiers in Cellular and Infection Microbiology in July 2022, scientists uncovered compelling evidence that the trillions of bacteria living in your intestines – known as the gut microbiome – could play a crucial role in ASD. While genetics and environmental factors are well-established contributors to autism, research now suggests that gut bacteria might influence brain development, behavior and even symptoms of the disorder.
It may seem strange to think that the gut has anything to do with the brain but scientists have long known that the two are intimately connected through what is called the gut-brain axis. This communication network operates through hormones, the immune pathways and the nervous system.
The gut is home to the enteric nervous system (ENS), sometimes called the “second brain.” It contains millions of neurons that interact with the central nervous system, particularly through the vagus nerve – a direct line from the gut to the brain. But nerves are not the only players in the system. The gut is also teeming with bacteria that produce neurotransmitters, including serotonin, which affect mood and cognition. In fact, nearly 90 percent of the body’s serotonin is produced in the gut, not the brain.
This connection is so strong that disruptions in the gut microbiome have been linked to anxiety, depression and neurodevelopmental disorders like ASD. Now, scientists are asking a critical question: Could restoring the gut balance improve autism symptoms?
Gut microbiome imbalance may be linked to ASD
In the U.S., the prevalence of autism among children has risen over four-fold in the past two decades, from 6.7 cases per 1,000 (1 in 150) in 2000 to 27.6 per 1,000 (1 in 36) in 2020. ASD is characterized by challenges with communication, repetitive behaviors and social interaction. While no single cause has been identified, researchers are exploring how early gut microbiome development might shape the brain.
Studies suggest that gut microbiome imbalances, known as dysbiosis, may be linked to ASD. Several key factors influence this early microbial landscape, including the method of birth delivery, antibiotic overuse and diet.
Read More: The gut-brain connection
