Are stomach pain and bloating signs of an unhealthy gut?

Stomach pain and bloating are the two most characteristic complaints of Irritable Bowel Syndrome (IBS). IBS is a so-called 'functional' bowel disorder: no tissue damage is visible, yet the gut does not work properly. The same complaints can, however, also point to other conditions, such as an abnormal overgrowth of bacteria or fungi in the small intestine, or to stomach problems such as slow gastric emptying. That makes an accurate diagnosis important.

These complaints are therefore not automatically a sign of an 'unhealthy gut' in the sense of visible damage or inflammation. Yet studies show that in some people the immune system in the gut wall reacts to certain foods, which can trigger or worsen symptoms. This is biologically interesting, but has not yet been proven as a cause in most patients.

People troubled by IBS symptoms may benefit most from a low-FODMAP diet: this involves restricting fermentable carbohydrates that irritate the gut. In an analysis of thirteen randomised studies involving nearly a thousand patients, this diet worked best of all the approaches examined. The likelihood of no improvement was 33% lower than with a normal eating pattern. A word of caution: the diet is not intended as a permanent lifestyle. Following it for a long time without reintroducing foods can reduce the number of beneficial gut bacteria.

A personalised elimination diet, based on which foods trigger a response from your immune system, also showed positive results in one randomised study: 60% of participants felt clearly better, compared with 42% in the control group. Larger studies still need to confirm this.

Gentle aerobic exercise such as walking, swimming or cycling appears to have a favourable effect on the gut microbiome and to relieve IBS symptoms, although the evidence for this is still limited and the ideal intensity and duration are not known. Training too hard can actually make symptoms worse.