Irritable Bowel Syndrome

Irritable Bowel Syndrome (RDS) is a very common, chronic condition of the gastrointestinal tract (GIT) characterized by abdominal pain and changes in bowel habits, although there is no known organic cause. The condition is diagnosed according to the Rome Criteria, a classification system based on symptoms, using Rome IV, the most recent guidelines. The majority of people affected with IBS not only suffer from gastrointestinal complaints, but also experience psychological disorders such as anxiety or depression, and thus a reduction in quality of life. In recent years new insights have been gainend to understand the pathophysiology of IBS, but the background of the symptom progress still remains unclear to date. However, physiological and psychological aspects have been defined in the etiology, with the gut-brain-axis probably playing a crucial role in patients with this condition. Despite numerous studies leading to a better understanding of the pathophysiology of of IBS, the therapy still remains symptom-based.  Although IBS is not associated with increased mortality, the disease still represents a burden for the individual with a reduced quality of life. 
 

IBS is considered a multifactorial disorder with emphasis on gastrointestinal dysmotility, visceral hypersensitivity, inflammation and altered gut microbiota, all leading to the symptomatology. Since stress has been identified as a component in the development of this condition, many studies investigated the main elements of the stress response system, the hypothalamic-pituitary-adrenocortical (HPA) axis and the autonomic nervous system (ANS) in relation to IBS. In a study of the risk factors for the development of IBS in military personnel, Riddle et al. found an increased risk in cases of infectious gastroenteritis and also in patients with increased stress levels, anxiety, depression and post-traumatic stress disorder (PTSD). This study describes the interaction between the brain and the gut in patients with IBS, also known as the gut-brain-axis (BGA). According to Stasi et al. and Weaver et al. Patients with IBS were found to have distinctions in the central processing mechanisms of the BGA in comparison to healthy controls, as well as differences in brain structure, functional responsiveness and connectivity. Although there has been great development in the understanding of IBS, the diagnosis of the patient is still mainly based on exclusion and the treatment is tied to the patient’s symptoms.
 

Chey et al. state that the diagnosis of IBS is made by the presence of specific symptoms in the absence of an organic disease. According to the current Rome IV criteria of the American Gastroenterological Association from 2016, IBS is classified as a functional bowel disease that has been present for more than six months and occurs at least once a week for the past three months. The diagnostic criteria includes abdominal pain, which is associated with the following factors: enhancement with defecation, change in stool consistency and stool frequency. The Rome IV criteria classify IBS patients according to their prevalent stool patterns: diarrhea (IBS-D), constipation (IBS-C), mixed stool (IBS-M) or unsubtyped (IBS-U). Since IBS is a diagnosis of exclusion, other diseases with similar symptoms such as inflammatory bowel disease (IBD), celiac disease (CD), bile acid malabsorption, microscopic colitis (MC), food intolerances and colon cancer must be excluded by appropriate examinations. In addition, various laboratory tests are available which can support the diagnosis of suspected IBS through various parameters. 
 

IBS is a multi-factorial condition with various treatment approaches. Depending on the subtype of IBS, pharmacological management is based on the predominant intestinal symptoms of the patient with appropriate medication to relieve abdominal pain. In addition, non-pharmacological interventions such as exercise, dietary changes and other alternative approaches are available as therapeutic measures. A particular focus of clinical research is the improvement of IBS symptoms through dietary changes, because the diet can trigger symptoms through stimulation of various receptors. Additionally, many patients with IBS are more likely to develop intolerances to foods or food components, including lactose, wheat, gluten, FODMAPs (short for fermentable oligosaccharides, disaccharides, monosaccharides and polyols) and also fructose malabsorption. In a recent study of patients with IBS-D, Aziz et al. found that a gluten free diet for six weeks resulted in significantly improved values for the symptom severity of fatigue, depression, anxiety and quality of life. In a study by Lacy et al. the low-FODMAP diet was studied in patients with IBS and led to an improvement in abdominal symptoms in some patients. In addition, a systematic review and meta-analysis by Moayyedi et al. of 14 studies found that administration of a soluble dietary fibre supplement had positive effects on symptoms in patients with IBS. Alongside the dietary changes, the influence of the gut microbita has a great impact on gastrointestinal processes and the health in general. Some studies have reported a positive effect of probiotics in the treatment of flatulence, bloating, abdominal distension and pain in patients with IBS. Furthermore, physical activity also appears to have an influence on the severity of IBS symptoms. Johannesson et al showed in a randomized control trial with 102 patients that a intervention of 12 weeks with moderately increased physical activity can reduce the severity of symptoms in IBS patients, leading to a higher quality of life. Schumann et al. reported in a systematic review including six randomized controlled trials, also on the advantages of yoga for quality of life in patients with IBS, but also on anxiety, and gastrointestinal symptoms. In addition, treatments from Traditional Chinese Medicine (TCM) such as acupuncture (use of needles), electroacupuncture (EA) and moxibustion (use of heat) can also have a positive effect on patients with IBS.
 

A new approach to the therapeutic possibility of irritable bowel syndrome includes the optimization of the intestinal flora by probiotics. The use of a sensible combination of probiotic intestinal bacteria strains (probiotics) in sufficiently high concentrations in combination with indigestible plant fibers (prebiotics) shows good results in maintaining intestinal health. While probiotics can reduce foreign colonization of the intestinal mucosa with pathogenic germs and limit their growth, prebiotics serve as valuable fodder for the probiotics.  In this context, a clinical study from 2021 was able to document the effectiveness of probiotics in 51 patients diagnosed with irritable bowel syndrome. After eight weeks of use, the patients showed a reduction in symptoms, an increase in quality of life, and an improvement in pain. 
 

The curcuminoids contained in Turmeric (Curcuma longa) have anti-inflammatory, antioxidant and immunomodulatory properties. The anti-inflammatory effect of the curcuminoids is achieved by inhibition of cyclooxygenase-2 (COX-2) and lipoxygenase (LOX) and by normalization of NO-synthase (iNOS). the imbalance in the activation of COX-2 and/or iNOS is thought to be related to tumor diseases and inflammatory processes.

Acute inflammatory processes often show a high content of pro-inflammatory and immunosuppressive eicosanoids, which are formed from arachidonic acid. An increased supply of the omega-3 fatty acid eicosapentaenoic acid (EPA) inhibits this conversion process  which leads to more anti-inflammatory eicosanoids being formed.

Frankincense extract (Boswellia serrata) contains boswellic acids, which have a direct anti-inflammatory effect on cells by inhibiting the leukotriene B activity.  

Due to its astringent effect, green tea extract can reduce the permeability of the intestinal mucosa  and prevent the penetration of antigens and pathogenic germs. The constituent epigallocatechin-3-gallate is an electron donor and thus acts as an effective antioxidant in the inflammatory process. These effects have been demonstrated in both the small and large intestine.

Chamomile extract strengthens the healing process through its antiphlogistic and granulation-promoting properties.

L-glutamine plays a central role in building and maintaining cell systems. Cells with high division rates, such as the cells of the immune system and the mucosa cells of the small intestine, depend on an adequate supply of the amino acid glutamine. In addition, L-glutamine, as a precursor of glutathione biosynthesis, is a key component in maintaining antioxidant status.

Zinc is closely linked to defence and healing processes and promotes the restoration of a healthy intestinal mucosa, which means that supplementation with zinc plays an important role in the therapy of a variety of gastrointestinal diseases. Furthermore, inflammatory changes in the intestinal mucosa often result in losses of vitamins and trace elements, which can lead to a poor supply of zinc. Both zinc and vitamin C are closely associated with immune and healing processes and promote the restoration of a healthy intestinal mucosa.

Irritable bowel syndrome often occurs in combination with increased physical or mental stress. Long-term high stress hormone levels cause an increase in metabolism and promote inflammatory processes, which can lead to impaired gastrointestinal functions and malabsorption-related micronutrient losses. An increased intake of all B-complex vitamins can have a therapeutic effect on stress-related symptoms.

Psyllium contains mucilage (galacturonic acid, xylose, ramnose and arabinose) which have a high water-binding capacity. By swelling in water they can increase their volume by 10 to 20 times. This swelling ability makes the stool softer and more voluminous. The increase in volume stimulates peristalsis through the resulting pressure on the intestinal wall and thus regulates bowel emptying. In the case of diarrhea, on the other hand, the transit time is extended due to the binding of water which helps to relieve symptoms of diarrhea. Studies have shown that psyllium has a significantly better effect on irritable bowel than wheat bran. In therapeutic use, psyllium is therefore superior to bran preparations as a source of dietary fibre.

A disturbed intestinal flora can contribute to the development of various intestinal dysfunctions via chronic inflammatory processes. The use of a sensible combination of probiotic strains of intestinal bacteria (probiotics) in sufficiently high concentrations in combination with indigestible plant fibres (prebiotics) shows good results in maintaining intestinal health. While probiotics can reduce the foreign colonisation of the intestinal mucosa with pathogenic germs and restrict their growth, prebiotics serve probiotics as valuable feed. 

One of the most frequent causes of digestive problems in the sense of insufficient breakdown of food components (maldigestion) is a loss of function of the pancreas (pancreatic insufficiency). The complaints that arise from this respond well to the administration of digestive enzymes, as they support the digestion of proteins, carbohydrates and fats and improve digestion. Possible enzymes to support digestive performance include pancreatic enzymes (pancreatin) and vegetable enzymes from pineapple (bromelain) and papaya (papain) as well as lactase, which breaks down lactose.

Due to the inflammatory changes in the intestinal mucosa, absorption disorders often occur, which lead to high gastrointestinal losses of electrolytes, vitamins and trace elements and result in a suboptimal vitamin status. In addition, interactions with drugs used can cause a nutrient imbalance. A targeted supplementation of the affected micronutrients such as zinc, vitamin C, iron and vitamin D is therefore advisable.