Gut Bacteria That Produce Serotonin Could Lead to New IBS Treatments, Study Finds

Breakthrough Discovery in Gut-Brain Connection

Researchers from the University of Gothenburg have made a significant discovery that could transform treatment approaches for irritable bowel syndrome (IBS), according to their newly published findings. The study reveals that two specific gut bacteria—Limosilactobacillus mucosae and Ligilactobacillus ruminis—can independently produce biologically active serotonin, a neurotransmitter crucial for digestive health.

Breakthrough Discovery in Gut-Brain Connection
Beyond Previous Understanding of Serotonin Production
Restoring Function in Animal Models
Clinical Implications for IBS Patients
Complex Microbial Interactions
New Treatment Pathways

Beyond Previous Understanding of Serotonin Production

While earlier research had established that gut bacteria influence serotonin production by human cells, this study demonstrates for the first time that certain microbes can manufacture the neurotransmitter directly, sources indicate. Previously, serotonin production in the gut had been primarily attributed to enterochromaffin cells in the intestinal wall lining.

“It is incredibly fascinating how the gut bacteria can produce bioactive signaling molecules that affect health,” said co-lead author Fredrik Bäckhed, professor of molecular medicine at Sahlgrenska Academy at the University of Gothenburg, according to the report.

Restoring Function in Animal Models

When researchers administered these serotonin-producing bacteria to germ-free mice with serotonin deficiency, they observed multiple positive effects, the study states. Not only did serotonin levels increase, but the density of nerve cells in the colon also improved. Most significantly, the bacteria corrected intestinal transit time, effectively regulating previously dysfunctional bowel movements.

The researchers noted that “intestinal bacteria can form signaling substances such as serotonin, which may be the key to understanding how the intestine and its inhabitants can affect our brain and behavior,” according to their published conclusions.

Clinical Implications for IBS Patients

The discovery has particular relevance for the estimated millions worldwide suffering from IBS, a common gastrointestinal disorder whose exact causes remain unknown. Analysis of human subjects revealed that people with IBS had lower levels of L. mucosae in their stool compared to healthy individuals, suggesting a potential connection between these bacteria and the condition.

“Our results indicate that certain intestinal bacteria can produce bioactive serotonin and thus play an important role in intestinal health and open new avenues for the treatment of functional gastrointestinal disorders such as IBS,” said Magnus Simrén, a Professor of medical gastroenterology at Sahlgrenska Academy, according to the research documentation.

Complex Microbial Interactions

The findings also suggest that serotonin synthesis in the gut microbiome may require collaboration between multiple bacterial species. In this case, L. mucosae and L. ruminis appear to work together to produce the neurotransmitter, indicating that microbial communities function as interconnected systems rather than individual actors., according to emerging trends

Researchers noted that “future research may investigate whether serotonin-producing bacteria could promote physiologic serotonin levels in patients suffering from dysfunctional intestinal motility,” pointing toward potential therapeutic applications.

New Treatment Pathways

This breakthrough discovery provides a completely new approach to developing treatments for IBS and other functional gastrointestinal disorders. Rather than targeting symptoms with conventional medications, future therapies might involve restoring or enhancing specific serotonin-producing bacterial populations in the gut microbiome.

The research team emphasized that their findings “identify human co-isolated L. mucosae and L. ruminis strains that synthesize serotonin in vitro and modulate enteric serotonin levels, enteric innervation, and intestinal transit time in vivo,” according to their published methodology and results.