How does gut bacteria diversity in Crohn's Disease compare to healthy people?
Gut bacteria diversity refers to the variety of different microbial species living in your intestines. In Crohn's disease, this diversity is often reduced, a state called dysbiosis. Research consistently shows that people with Crohn's have a less diverse and less stable gut microbiome compared to healthy people, with specific changes in the types of bacteria present.
What the research says
Multiple studies confirm that gut bacteria diversity is lower in Crohn's disease. A large 2017 study analyzing over 2000 fecal samples found that dysbiosis was significantly greater in Crohn's disease than in ulcerative colitis, with reduced diversity and a less stable microbial community 10. A 2021 study also reported lower alpha diversity (a measure of within-sample diversity) in Crohn's disease compared to healthy controls 11.
The types of bacteria also differ. In Crohn's disease, there is often an increase in potentially harmful bacteria like Proteobacteria and a decrease in beneficial bacteria that produce short-chain fatty acids (SCFAs), such as Firmicutes 11. A 2024 study found that people with Crohn's had lower plasma concentrations of secondary bile acids, which are produced by gut bacteria, suggesting altered microbial function 9. The oral microbiome is also affected: a meta-analysis of 25 studies found reduced oral microbial diversity in Crohn's disease 4.
These microbial changes are linked to inflammation. The NF-κB pathway, a key driver of inflammation, is activated by microbial imbalances, contributing to intestinal inflammation and a 'leaky gut' 3. Early-life antibiotic use, which disrupts the microbiome, is associated with a higher risk of developing Crohn's disease 2.
What to ask your doctor
- Could a stool test or microbiome analysis help assess my gut bacteria diversity?
- Are there dietary changes, such as increasing fiber or prebiotics, that might support a healthier gut microbiome?
- How might my current treatments (like biologics or enteral nutrition) affect my gut bacteria?
- Should I consider probiotics or other supplements to improve microbial diversity?
- Is there any role for fecal microbiota transplantation in Crohn's disease?
This question is drawn from common patient questions about Gastroenterology and answered using cited medical research. We do not provide individualized advice.