Abdominal pain, bloating, changes in stool frequency and consistency. These are just some of the symptoms associated with Irritable Bowel Syndrome (IBS), a chronic functional disorder whose origins are unknown. It has no known treatment, only recommendations to keep symptoms at bay. In Western countries, almost two out of ten gastroenterology consultations are motivated by this disorder.


Professor Magnus Simrén, researcher at the University of Gothenburg (Sweden), is the Chairman of the United European Gastroenterology (UEG) Scientific Committee. He attended the 4th Gut Microbiota for Health World Summit, where we had a chance to interview him about IBS.


How is IBS clinically identified?

It can only be identified by the symptoms. It is characterized by a combination of abdominal pain, discomfort and abnormal bloating, three factors that are closely related. When doctors, for instance, research into the condition and take blood samples, they find test results come back normal. So, there is no need to do an extensive clinical check in all patients if they have a very specific symptom pattern of IBS. Rather, what the doctors need to look for is whether there are other alarm signals, like blood in the patient’s stool.


Do psychological conditions influence IBS?

Although IBS is not a psychological condition, symptoms may worsen due to psychological factors, but also due to diet. Psychological factors do affect the symptoms but they are not the only cause.


Is it a serious condition?

It is not serious from a medical point of view – you will not die from IBS and the disorder will not evolve into a more serious illness. But it affects people’s lives quite substantially, reducing their quality of life and their ability to work and function normally in society. So from a personal point of view, it is serious. It does not imply every person suffering from IBS is dramatically affected; some people have very mild symptoms, whereas other people’s symptoms are really severe.


Are there any biomarkers that could be used to diagnose the disorder?

We are, in fact, looking for any useful clinical biomarkers – blood tests, stool tests or any other tests that we could possibly use to diagnose IBS. But for now we have not found anything, so the diagnosis relies on the typical symptom pattern.


Could alterations in microbiota be used as biomarkers?

Several studies have already shown that it seems there are alterations in gut microbiota composition in at least a subgroup of IBS patients compared to healthy control groups. Nevertheless, we still haven’t found specific background bacteria that could characterise IBS. Right now, the balance between different kinds of microbes is which has been altered in these patients. There is so much happening in the field now, with papers coming out almost every day or quite frequently – it’s still in its infancy!


So what is the importance of the microbiota?

The gut microbiota interacts with all the functions of the body and that is why it is essential to have healthy gut bacteria. If there are alterations in the microbiota’s composition, it may affect different organs, even the brain, which is a very interesting new field.


The brain-gut axis?

Exactly! We do not understand this relationship but we know there is an interaction between what happens in the gut and how the brain reacts and even behaves. In animal research, we are seeing that if we change the composition of the gut microbiota, the behaviour of rodents also changes! There is even some data from humans, with some studies showing that alterations in the microbiota of healthy females do affect the behaviour of their brains.


Nowadays it seems that gut microbiota is linked to many diseases, from Autism to Parkinson or Alzheimer’s disease

It’s always the case that when an area of scientific knowledge undergoes significant expansion, we may sometimes jump to wrong conclusions. I don’t think gut microbiota is the solution for everything. We need to be very careful. For instance, with IBS, some researchers say it is a microbiological disease but, in fact, we still have to show that. The only thing proven for the moment is that there are alterations that could be significant for the disorder, but maybe only for some IBS patients; we have yet to define the groups for which gut microbiota alterations are important. In this regard, we could manipulate the symptoms by altering gut microbiota composition, using different diets, as well as probiotics, antibiotics and prebiotics, for instance.


Could a possible treatment involve sport?

It has not been proven. There are no studies taking into account gut microbiota, sport and IBS. In my group, four years ago, we conducted a study where we asked patients to increase their physical activity and when they did, their gastrointestinal symptoms were reduced. However, we did not analyse their gut microbiota composition.


Can IBS be inherited?

There is some level of inheritance; some may be linked to genes and some may be linked to shared environmental factors. We know that IBS runs in families, so to say, but not one to one. It means that if your mother has IBS, it does not imply you will have it for sure, but you will have an increased risk of suffering from IBS. So, in part, IBS is due to genetic factors, but in a large part due to environmental factors including diet, lifestyle, stress levels and resilience capacity.