Chronic stress and alterations in the adolescent gut microbiome – new finding from a 2025 study

Introduction 

The gut-stress connection is becoming increasingly well recognised, with research highlighting clear links between the gastrointestinal system and the brain. This relationship operates through the gut-brain axis: a two-way communication network between the digestive system and the central nervous system. The vagus nerve is the primary physical pathway between the two, carrying signals in both directions. When a person is stressed, the brain sends signals  via the vagus nerve that can alter digestive function; speeding up or slowing down gut motility, or changing the secretion of digestive enzymes. This can lead to symptoms such as diarrhoea, constipation, bloating or cramping. These IBS type symptoms are considered a classic example of gut-brain axis dysfunction. 

Chronic stress has a more lasting impact on gastrointestinal health than a short-lived stress response, because the body's stress response stays ‘switched on’, involving ongoing activation of the sympathetic nervous system, or ‘fight-flight’ responses. Research shows that sustained stress can alter the gut microbiome, disrupting beneficial bacteria and allowing less favourable microbes to proliferate. 

Chronic stress and the microbiome in adolescents is an emerging area of research, as most studies to date have focused on adults or been weighted towards animal models. A notable 2025 study examined alterations in the human gut microbiome associated with chronic stress specifically in adolescents, defining changes in gut microbiota and potential health outcomes. These findings could help guide strategies for practitioners working with teenagers when stress is part of the clinical picture. 

Study method 

Researchers conducted a cross-sectional study of 124 adolescents aged 12-16 years. Stress was assessed using two validated self-report questionnaires: the Adolescent Life Events Scale (general life stressors) and the Study Stress Scale (academic pressure), both covering the preceding 12 months. Combined scores classified participants into low, medium or high stress groups. All 124 provided stool samples for 16S rRNA gene sequencing; a subset of 59 (the 30 highest and 29 lowest chronic stress scorers) underwent metagenomic sequencing. 

A Kruskal-Wallis test compared the three groups on sex, ethnicity, BMI, lifestyle, environmental factors, diet and parental characteristics. None differed significantly, indicating the adolescents were representative of the broader population, a pattern that also held within the 59 participant subgroup, ruling out these lifestyle factors as explanations for the microbiome differences observed between stress groups. 

Key findings

Limitations

While this study offers interesting findings, several limitations should be considered. As a cross-sectional study, it captures a single snapshot in time rather than long-term trends. The correlation found between microbiome alterations and stress does not establish causality (does stress alter the microbiome, does the microbiome influence stress resilience, or both?).

Stress was self-reported through a perceived stress measure rather than assessed objectively, and the small sample, drawn from students at one school in Xi'an, limits generalisability and raises the possibility of cultural bias. The Adolescent Life Events Scale and Study Stress Scale are tailored to specific populations and languages, so results may not be directly comparable across different tools or cultural settings. Other factors such as physical activity, diet and sleep were not accounted for. Larger, cross-cultural, longitudinal studies could offer deeper insight to guide future strategies. 

Conclusion: 

This study addresses an under researched population and its findings align with the broader gut-brain axis literature while adding useful adolescent specific detail. It offers mechanistic clues linking chronic adolescent stress to downstream health risks, particularly a plausible pathway involving reduced SCFA production, increased inflammatory signalling and altered energy metabolism. 

For practitioners working with teenagers, this reinforces the value of considering a gut-brain axis lens for gastrointestinal symptoms in stressed adolescents, rather than viewing them in isolation. Chronic academic or life event stress in particular may warrant closer attention as a contributing factor, given the sustained sympathetic activation this study links to microbial and metabolic change. 

References: 

Li, Y. et al. (2025) 'Chronic stress is associated with altered gut microbiota profile and relevant metabolites in adolescents', BMC Microbiology, 25, article 423. doi: 10.1186/s12866-025-04094-1