Irritable Bowel Syndrome and
gut microbiota

8 June 2021 – 2 min read

Irritable bowel syndrome (IBS) is a very common functional gastrointestinal disorder  that affects around 580 million people worldwide.  It is a major women’s health issue since 2 out of 3  individuals who report IBS in the community are female.

The latest consensus guidelines (Rome IV) define IBS as: “A gut-brain disorder characterized by recurrent abdominal pain associated to changes in frequency or appearance of stools at least 1 day per week for the last 3 months” 1

IBS symptoms include  abdominal pain, discomfort , bloating or distension and gut-specific anxiety. 

All these features interfere with the daily life of many patients, having a significant detrimental effect in their quality of life.

IBS, a misdiagnosed disease

One of the most challenging parts of IBS is its diagnose. The International Foundation for Functional Gastrointestinal Disorders (IFFGD) estimates that 50% of IBS cases go unreported by patients or medical professionals, and the average time between onset of IBS and diagnosis is around six years. 

The number of symptoms that occur together and characterize IBS may confuse both patients and health care professionals and results in this long period of time until the final diagnose. It fatigues patients and may even get symptoms worse due to uncertainity and dicomfort.

Its pathophysiology is complex, and still incompletely understood, involving genetic, environmental, and psychological causes.

Several studies confirm unbalanced proportions of gut bacteria in IBS sufferers compared to healthy subjects 2,3

Key mechanisms in IBS pathophysiology include increased intestinal permeability, microinflammation and gut microbiota dysbiosis with associated visceral hypersensitivity. Altered gut-brain interactions (bidirectional communications between the gut and the brain), psychosocial distress, gastrointestinal motor disturbances, and food hypersensitivity are also involved.

The role of microbiota

The gastrointestinal tract is the major reservoir of microorganisms, with more than 2,000 bacterial species described.

Gut microbiota disbalances (so-called dysbiosis) have been linked to many pathologies, including gastrointestinal, immune and brain conditions.

Several studies confirm unbalanced proportions of gut bacteria in IBS sufferers compared to healthy subjects 2 . IBS dysbiosis is characterized by a reduction of Lactobacillus and Bifidobacteria, and an increment of Escherichia coli 3. Recent studies identified other bacterial groups abnormally increased in IBS including Actinomyces and Streptococcus species3

In our commitment to provide new therapeutic alternatives , we are developing several studies to demonstrate clinically outcomes in IBS patients by the administration of our patented probiotic strains.  

Check our finished and published clinical evidence related with this gastrointestinal disorder here

Authors: Mercè Mengual (Pharmacist) and Marta Pérez, PhD (Microbiologist)


1. Lacy, B. & Patel, N. Rome Criteria and a Diagnostic Approach to Irritable Bowel Syndrome. J. Clin. Med. 6, 99 (2017)  2.Vich Vila, A. et al. Gut microbiota composition and functional changes in inflammatory bowel disease and irritable bowel syndrome. Sci. Transl. Med. 10, eaap 8914 (2018).  3. Wang, L. et al. Gut Microbial Dysbiosis in the Irritable Bowel Syndrome: A Systematic Review and Meta-Analysis of Case-Control Studies. J. Acad. Nutr. Diet. 120, 565–586 (2020).