The cause of IBS is complex and is still not completely understood, involving genetic, environmental, and psychological causes. Research has identified some key mechanisms involved in the onset of symptoms -  

  • Increased intestinal permeability - allows an outflow of antigens through the intestinal wall, causing overstimulation of the immune system and acute inflammatory responses. Microinflammation  
  • Gut microbiota dysbiosis  
  • Visceral hypersensitivity - Visceral hypersensitivity produces an abnormal perception of pain caused a stimulus (i.e. food, stress or medication) that does not normally elicit pain, increased perception of bloating and increased worry about pain (gut-specific anxiety) 
  • Alerted gut-brain interactions – the two-way communication between our gut and brain. In those with IBS this communication can become unbalanced meaning their gut can overreact to certain triggers such as stress and anxiety. For more information, read out article on the gut-brain axis
  • Psychosocial distress 
  • Gastrointestinal motor disturbances - unable to control the motor functions of the digestive tract  
  • Food hypersensitivities  

Gut microbiota dysbiosis is when the gut becomes unbalanced and there is an overgrowth in pathogenic bacteria and an increase in good bacteria Research has shown a link between IBS and the gut microbiome - 

  • In those with post-infectious IBS there is alterations in the gut microbiome which is a likely contributor to IBS  
  • Small intestinal bacterial overgrowth often causes symptoms similar to those of IBS, in particular boating in relation to food intake  
  • Studies comparing the gut microbiome of IBS patients to healthy controls show that those with IBS have an altered gut microbiome as well as specific gut microbiome profiles being associated with particular symptoms of severity of disease  

Therefore, using friendly bacteria as a way to help manage IBS symptoms through several mechanisms of actions including modulating the gut microbiome has been suggested.  

Specific strains of friendly bacteria can positively interact with the gut microbiota, intestinal barrier and mucosal immune cells, targeting key pathophysiological aspects of IBS.  

Friendly bacteria can have several effects on patients to improve their IBS symptoms. IBS can be broken down into 3 main subtypes dependent on stools and the management of each subtype will vary -   

  • IBS-C (constipation)  
  • IBS-D (diarrhoea)  
  • IBS -M (mixed)  
  • Or IBS – U (unclassified) 

For research on specific bacterial strains and IBS management by subtype check out our article - “Friendly bacteria and IBS management” 

Friendly bacteria have several mechanisms by which they are able to help manage IBS symptoms - 

  • Improvement of intestinal permeability: friendly bacteria produce high quantities of po- lyphosphate granules (poly-P), molecules that are able to protect and enhance the intestinal barrier, reducing intestinal permeability.  
  • Reduction of inflammation: through the production of acetate and acetylcholine, which balance the inflammatory response in the gut mucosa.  
  • Gut dysbiosis correction: friendly bacteria have anti-pathogenic properties, inhibiting the growth of IBS-associated bacteria in the gut, positively interacting with the gut microbiota  

If you'd like to find out more, book a free 1:1 consultation with our in-house nutrition team.


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