Around one in ten people worldwide have IBS symptoms, including stomach pain, bloating, and bowel dysfunction, all of which can have a significant detrimental effect on a person’s life. The condition is known to have a genetic component and is further known to be more common in those with an anxiety condition.

The underlying biological causes of IBS are currently not well understood by clinicians. However, an international team of researchers have identified several genes that may begin to unravel the genetic origins of the gastrointestinal condition.

The research team, including more than 40 institutions, examined the genetic profile of more than 50,000 people diagnosed with IBS and compared them to 400,000 people without IBS. The results showed that the IBS was weakly related to heritability, indicating the importance of environmental factors in developing the condition.

Significantly, six influencing genes were found in the study to be associated with IBS. However, the research team was surprised to discover that the genes were not connected with the intestinal region but with the brain and potentially the nerves which relate to the gut.

Investigating this line of inquiry further, the research team examined the overlap between IBS susceptibility and other physical and mental health conditions. They discovered that the same six genes were also associated with increased risk for emotional and anxiety disorders, such as anxiety, depression, and insomnia.

The findings highlighting the relationship between the brain and gut may lead to new treatments

Professor Miles Parkes, University of Cambridge, stressed that the findings don't signify anxiety causes IBS or vice versa. He said: “IBS is a common problem, and its symptoms are real and debilitating. Although IBS occurs more frequently in those who are prone to anxiety, we don’t believe that one causes the other – our study shows these conditions have shared genetic origins, with the affected genes possibly leading to physical changes in brain or nerve cells that in turn cause symptoms in the brain and symptoms in the gut.”

Curiously the study also found that people with mental health and IBS symptoms were more likely to have been treated frequently with antibiotics during childhood. The researchers said that this suggests that altering the gut flora may increase the risk of adult IBS symptoms and influence neurodevelopment and consequentially mood.

The research team concluded that they hope that their findings will lead to the development of new treatments in the future. The study's co-senior investigator Dr Luke Jostins, University Oxford, commented: “We anticipate that future research will build on our discoveries, both by investigating the target genes identified and exploring the shared genetic risk across conditions to improve understanding of the disordered brain-gut interactions which characterise IBS.”