The protective lining of the gut, known as the intestinal barrier, acts as a filter allowing nutrients from food to enter the bloodstream but preventing pathogens, e.g. harmful bacteria, from making the crossing. As highlighted in a recent article by Harvard Health Publishing, everyone has a leaky gut to some extent, selectively allowing substances to enter or exit. However, an increase in gut permeability is a potential problem.
It has been suggested that people with ME/CFS may have alterations to the intestinal barrier, making it easier for pathogens to leak out into the blood circulation – a concept termed ‘leaky gut syndrome’. Furthermore, research theorises that the immune system of individuals with ME/CFS is suppressed, therefore, fails to mount a ‘normal’ response to pathogens in the blood.
In the realm of exercise, intense physical activity in healthy individuals is known to increase gut permeability, potentially causing endotoxemia—bacterial toxins in the blood. When functioning correctly, the immune system plays a crucial role in eliminating these harmful substances from the blood. One might expect that a potentially compromised gut barrier in individuals with ME/CFS might allow more pathogens through during exercise, overwhelming a weakened immune system. A recent study explored this and suggested that certain symptoms of endotoxemia such as fatigue, cognitive changes, nausea, and headache mirror symptoms reported by individuals with ME/CFS during post-exertional malaise (PEM).
It is worth emphasising that ‘leaky gut syndrome’ is still a topic of debate, and more research is needed to get a better picture of the role of the gut in ME/CFS.
Read more about an ongoing ME Research UK-funded study exploring the gut microbiome.
