Scientists are uncovering surprising connections between the gut and the brain, and new research strengthens that link. A team at Comenius University has found that children diagnosed with autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), and anorexia nervosa (AN) share similar disruptions in their gut microbiome. Although these conditions differ widely in symptoms, their digestive ecosystems appear to mirror one another in unexpected ways.
A Shared Gut Signature
Researchers analyzed stool samples from 117 children and discovered that all three groups displayed a significantly higher ratio of Bacteroidetes to Firmicutes compared with healthy peers. This shift often signals an altered microbial balance. The team also observed that children with autism and ADHD had reduced microbial diversity, indicating that their gut ecosystems may struggle to adapt. Beneficial bacteria such as Bifidobacterium and Faecalibacterium appeared in lower amounts, while genera like Escherichia and Desulfovibrio increased in some groups, further highlighting the imbalance.
Hormones and the Gut-Brain Link
The researchers expanded their work by measuring hunger- and satiety-related hormones. Children with ADHD showed lower levels of peptide YY, a hormone that helps regulate appetite. In the anorexia group, levels of leptin, ghrelin, and PYY dropped noticeably. These hormonal patterns suggest that eating behaviors may shape the gut microbiome, while microbial changes may, in turn, influence appetite and brain signaling, creating a powerful gut-brain feedback loop.
What the Findings Suggest
Although the study examined a small group, it reveals a potential biological connection across these seemingly unrelated conditions. The findings support the growing belief that the gut-brain axis plays a significant role in neurodevelopmental and psychiatric disorders. While researchers have not yet determined whether microbial imbalances cause or result from these conditions, this work opens the door for future microbiome-based therapies.
