Early-life gastrointestinal inflammation and the developing brain: Unravelling the pathways to long-term cognitive dysfunction.

The gut-brain axis (GBA) is a complex, bidirectional communication network critical to integrating central nervous system functions with gastrointestinal (GI) health. This review examines how disruptions to the GBA during the critical early-life developmental window - a period of rapid neurogenesis and microbial colonization - contribute to long-term neurocognitive and psychiatric vulnerabilities. Evidence from animal models demonstrates that early-life stress, antibiotics, and infection induce sustained neuro-inflammation and alter microglial function, leading to long-term behavioral and cognitive impairments in adulthood. Human studies corroborate these findings, revealing that severe early GI insults, such as necrotizing enterocolitis, confer a high risk (40%) of global neurodevelopmental impairment and specific attention deficits. Chronic inflammatory conditions similarly impact the central nervous system: A high burden of early severe enteric infection is an independent risk factor for diminished intelligence quotient (IQ) and executive function, while conditions like celiac disease and inflammatory bowel disease are associated with persistent deficits in attention, processing speed, memory, and executive function. These clinical outcomes are strongly linked to systemic inflammation [elevated interleukin-6, kynurenine-to-tryptophan (Kyn:Trp) ratio], micronutrient deficiencies (iron, vitamin B12, folate), and structural white matter changes in the brain. Furthermore, chronic GI disease imposes a significant psychiatric burden, with high comorbidity of anxiety and depression often mediating poor health-related quality of life, particularly in pediatric inflammatory bowel disease. The findings underscore the necessity for a shift in clinical practice: Chronic GI disease in early life must be recognized as a red flag for neurocognitive risk. We advocate for a multidisciplinary approach encompassing early neurodevelopmental follow-up for high-risk groups and routine screening for cognitive and emotional comorbidities. Future research must focus on long-term prospective cohorts, identifying precise mechanistic biomarkers (metabolomics, microbiome signatures), and conducting interventional trials targeting the GBA to mitigate these long-term functional consequences.