The diagnosis “irritable bowel syndrome” is often made when no other physical cause can be found for digestive symptoms. However, the term is quite vague and only describes the symptoms without uncovering their true causes. So what does “irritable bowel syndrome” really mean?
Not a diagnosis, but a collective term
The label “irritable bowel syndrome” (IBS) is often used when patients experience recurring abdominal pain, bloating, and irregular digestion, yet no structural or organic cause can be identified. However, IBS is not a concrete medical finding but rather a collective term for a wide range of symptoms whose origins remain unclear. Studies suggest that 60-80% of people diagnosed with IBS show signs of gut dysbiosis, an imbalance in the intestinal microbiota (Videlock & Mawe, 2014). This dysbiosis may be a key factor contributing to their symptoms.
In addition, many individuals with IBS have a compromised intestinal lining, which reduces barrier function and can affect the absorption of nutrients and toxins. The communication between the nervous system and the digestive system also plays a crucial role.
The nervous system and its role in digestion
The nervous system plays a central role in regulating digestion and influences how the body responds to food intake and stress. It consists of two main parts: the somatic nervous system and the autonomic nervous system.
The somatic nervous system is responsible for the conscious control of muscles. It allows voluntary movements such as swallowing. Although it does not directly regulate digestion, it influences certain processes like food intake. The autonomic nervous system, on the other hand, controls digestion unconsciously and is divided into two key components: the sympathetic and the parasympathetic nervous systems.
The sympathetic system is often referred to as the “fight-or-flight” system. It is activated in stressful or threatening situations and prepares the body for action and alertness. However, this activation inhibits digestion, as the body directs its energy toward dealing with stress. An overactive sympathetic system, such as in cases of chronic stress, can worsen digestive issues like bloating, diarrhea, or constipation.
The parasympathetic system acts as the counterpart, promoting relaxation and recovery. It supports digestion by stimulating intestinal movement and encouraging the production of digestive enzymes and fluids. During calm and stress-free periods, an active parasympathetic system ensures efficient digestion and a healthy gut function.
An imbalance between these two systems, often caused by stress, can lead to symptoms associated with irritable bowel syndrome. The function of the autonomic nervous system can be measured using heart rate variability (HRV). A low HRV indicates excessive sympathetic activity, while a higher HRV reflects better parasympathetic function and a more relaxed digestive state.
The nervous system and its role in digestion
Unfortunately, the underlying cause is often not examined in detail, as diagnostics usually focus on standard tests such as lactose or fructose intolerance tests, endoscopies, or ultrasound examinations. While these procedures can detect intolerances, structural changes, or inflammation, they do not identify functional disturbances of the gut, such as dysbiosis or a weakened mucosal barrier. As a result, patients are often told, “You just have to live with it.” This general statement overlooks key aspects of gut health and prevents targeted treatment. In reality, the symptoms labeled as irritable bowel syndrome often have an underlying cause that can be identified and addressed through more comprehensive diagnostics and an individualized approach.
