Irritable Bowel Syndrome (IBS) is one of the most common digestive conditions, affecting millions of people worldwide. It is typically characterised by symptoms such as abdominal pain, bloating and changes in bowel habits.
Although the exact causes of IBS are not fully understood, researchers increasingly recognise that it involves a complex interaction between the digestive system, the nervous system and the gut microbiome.
The gut microbiome — the trillions of microorganisms living in the digestive tract — plays an important role in digestion, immune regulation and gut signalling. Scientists are now exploring how changes in microbiome composition may influence digestive symptoms associated with IBS.
Understanding this relationship may help explain why gut health has become an important area of interest in IBS research.
Founder Insight
Hanna Sillitoe first became interested in the role of the gut microbiome while recovering from severe psoriasis. During this time she began exploring research showing how gut bacteria influence digestion, inflammation and immune responses.
This discovery sparked a deeper interest in how the microbiome may influence many aspects of health, including digestive balance and gut wellbeing.
What Is IBS?
Irritable Bowel Syndrome (IBS) is a functional gastrointestinal disorder, meaning that symptoms occur without visible structural damage to the digestive tract.
People with IBS may experience symptoms such as:
- abdominal pain or discomfort
- bloating
- diarrhoea
- constipation
- alternating bowel habits
Symptoms can vary widely between individuals and may fluctuate over time.
IBS is thought to involve several interacting factors, including changes in gut motility, gut sensitivity, communication between the gut and brain, and changes in the gut microbiome.
Because of this complexity, researchers increasingly study IBS as a condition involving multiple systems within the body.
The Gut Connection
The Gut–Brain–Microbiome Axis
The digestive system and the brain communicate through a network often referred to as the gut–brain axis. The gut microbiome plays an important role within this communication system.
Gut microbes interact with immune cells, influence metabolic processes and produce compounds that affect signalling within the nervous system.
Microbiome diversity
Research has found that people with IBS may have differences in gut microbiome composition compared with healthy individuals. Some studies have observed reduced microbial diversity in people experiencing IBS symptoms.
Fermentation and gas production
Gut bacteria ferment certain carbohydrates and fibres that reach the large intestine. During this process they produce gases such as hydrogen and methane.
In some individuals, changes in fermentation patterns or gas handling within the digestive tract may contribute to symptoms such as bloating or discomfort.
Gut sensitivity
People with IBS may experience increased sensitivity within the digestive system. Researchers are exploring how microbiome interactions with the nervous system may influence how digestive sensations are perceived.
Inflammation and immune signalling
Although IBS is not typically considered an inflammatory disease, some studies suggest that subtle immune activation within the gut may occur in some individuals. The microbiome may influence these immune responses.
What Research Shows
Interest in the relationship between IBS and the gut microbiome has grown significantly over the past two decades.
Key research findings include:
• Microbiome differences in IBS – Several studies have identified differences in gut microbiome composition in people with IBS compared with healthy individuals.
• Post-infectious IBS – Some people develop IBS following a gastrointestinal infection, suggesting that changes in gut bacteria may influence the condition.
• Microbiome and gut signalling – Research suggests that gut microbes may influence communication between the digestive system and the nervous system.
• Probiotics and IBS research – Studies have explored how probiotics may influence digestive symptoms by affecting microbiome balance.
Although IBS remains a complex condition with many contributing factors, research continues to explore how microbiome composition and diversity may influence digestive function and gut sensitivity.
Sources
Qin J et al. A metagenome-wide association study of gut microbiota in IBS. Nature, 2012.
Jeffery IB et al. An irritable bowel syndrome subtype defined by species-specific alterations in faecal microbiota. Gut, 2012.
Tap J et al. Identification of an intestinal microbiota signature associated with severity of IBS. Gastroenterology, 2017.
Ford AC et al. Efficacy of probiotics in IBS: systematic review and meta-analysis. American Journal of Gastroenterology, 2014.
Supporting the Microbiome
Maintaining a healthy and diverse microbiome may help support digestive balance.
Several habits may help support gut health.
Eat a diverse range of plant foods
Plant diversity provides fibre that helps nourish beneficial gut bacteria.
Increase fibre gradually
Gradually increasing fibre intake allows the digestive system to adapt to fermentation processes.
Include fermented foods
Fermented foods such as sauerkraut, kefir and kimchi contain naturally occurring microorganisms that may help support microbiome diversity.
Support healthy lifestyle habits
Sleep, stress management and regular physical activity can all influence microbiome balance.
Consider probiotic support
Some people choose to support their microbiome with probiotics — live microorganisms designed to help maintain microbial balance within the digestive system.
Common Questions About IBS and Gut Health
Can gut bacteria affect IBS?
Researchers have found differences in microbiome composition in some people with IBS, suggesting that gut bacteria may influence digestive function.
Can probiotics help IBS?
Some studies have explored how probiotics may influence digestive symptoms in people with IBS. Results vary depending on the strains used and individual factors.
What foods help support gut health?
Foods rich in fibre and plant diversity help nourish beneficial gut bacteria. Fermented foods may also support microbiome diversity.
Conclusion
Irritable Bowel Syndrome is a complex digestive condition influenced by multiple factors, including gut motility, sensitivity and communication between the digestive system and the brain.
Increasingly, research suggests that the gut microbiome may play a role in digestive signalling, fermentation patterns and immune interactions within the gut.
Maintaining a healthy and diverse microbiome may therefore help support overall digestive balance and gut wellbeing.
Some people choose to support their microbiome with probiotics — live cultures designed to help maintain a healthy balance of gut bacteria. Learn more about our Multi-Strain Biotic and how it supports gut health.