An academic team from the University of Birmingham led an unprecedented study that compiled primary microbiome data from multiple studies, involving more than 1,700 children and adults from 11 countries, who were newly diagnosed and before any treatment began.
The results showed that people with Crohn's disease or ulcerative colitis, the most common type of inflammatory bowel disease, lose beneficial anaerobic bacteria responsible for digesting complex carbohydrates. In contrast, they experience an increase in oxygen-resistant bacteria, which normally migrate from the mouth to the intestines.
Dr. Peter Rimmer, a consultant gastroenterologist and lead author of the study, explained: "The results give us an accurate picture of what happens in the gut at the onset of infection, and suggest that changes in oxygen levels and migration of bacteria from the mouth may be key factors in inflammation, paving the way for early diagnosis and new treatments."
The patients lack anti-inflammatory bacteria.
An increase in bacteria that grow in an oxygen-rich environment at the onset of the disease, including types that are commonly found in the mouth.
Differences between stool samples and biopsies, and between children and adults.
Microbiome patterns vary by geographic region, highlighting the need for global data to support future studies.
The different analytical methods used in studying the microbiome indicate the importance of standardization.
The results suggest the possibility of developing diagnostic tools for the early detection of bowel inflammation, as well as new treatment strategies that target the microbiome or modify oxygen levels in the intestines, especially for newly diagnosed patients.
The study supports the so-called "oxygen hypothesis," which suggests that increased oxygen in the gut lining may disrupt the microbiome balance and contribute to disease. It also highlighted the presence of oral bacteria such as Granulectella and Haemophilus in the gut, potentially providing new targets for treatment or prevention.
The study was published in the Journal of Gastroenterology.
