Food intolerances as a widespread condition: Professor Dr Sükrettin Güldütuna is one of the world’s most renowned gastroenterologists. His gastroenterology clinic in Frankfurt am Main is one of the leading outpatient clinics of its kind in Europe: Here, a team of highly skilled specialists works alongside the renowned expert to treat all conditions affecting the gastrointestinal tract, as well as the liver, gallbladder and pancreas. One of Prof. Güldütuna’s medical and scientific specialisms is food intolerances, the diagnosis of which requires a high level of expertise. The Leading Medicine Guide spoke to him about this fascinating topic.
Leading Medicine Guide: Prof. Güldütuna, haven’t food intolerances always existed?
Prof. Dr. med. Güldütuna: They have probably always existed, but the fact is that these intolerances are on the rise today. More and more people are complaining of problems after eating. In the past, these kinds of symptoms – heartburn, stomach ache, bloating, diarrhea – were grouped under the term ‘irritable bowel syndrome’. Gastrointestinal infections are discussed as one of the causes of irritable bowel syndrome, as they trigger a misdirected immune response, which can lead to food intolerances. To investigate their vague abdominal pain, patients underwent gastroscopy and colonoscopy; if the findings were normal, they were simply told they had irritable bowel syndrome. Patients were prescribed probiotics, antispasmodics or even antidepressants. Many symptoms were also simply dismissed as hypochondriacal or psychosomatic.
Leading Medicine Guide: When did the turning point come in gastroenterology?
Prof. Dr Güldütuna: To answer that, I might need to backtrack a little and explain that our discipline has been undergoing a paradigm shift for years. We are right in the thick of microbiome research and are constantly making new discoveries. The microbiome – the human gut flora, comprising trillions of different bacteria – is a microcosm in its own right, a separate ecosystem that keeps us healthy. But exactly how that happens, what processes are at work there and what can go wrong – we still don’t know for certain. Science is only just beginning to discover just how crucial the microbiome is to our vital processes.
Leading Medicine Guide: A landmark study with sensational results regarding food intolerances and so-called irritable bowel syndrome took place in 2014.
Prof. Dr. med. Güldütuna: Yes, you could say that. The Ärztezeitung wrote at the time, “New test finally brings peace to the gut”. The Kiel-based gastroenterologist Prof. Dr Annette Fritscher-Ravens used endomicroscopy to investigate what is happening in the small intestine of patients with irritable bowel syndrome. These were truly sensational findings. Using the endoscope, she introduced solutions containing the most commonly intolerable foods: cow’s milk, soya, yeast and wheat. She then used the microscope to observe how the intestinal villi reacted. And indeed – 60 per cent of these IBS patients showed an astonishing reaction within a few minutes. The cell clusters on the intestinal villi break down, defects develop in the epithelial cells of the intestine, and the intestinal mucosa becomes increasingly permeable – those affected then suffer from abdominal pain and bloating with a time lag. Medicine had been confronted with these symptoms, but until then it had not been possible to identify the process by which the symptoms developed. With confocal laser endomicroscopy, we now finally have a diagnostic tool that shows the intestinal mucosa’s reactions in real time.
Leading Medicine Guide: Why did previous diagnostic methods fail to yield results?
Prof. Dr. med. Güldütuna: Samples were taken and sent to the laboratory, but this yielded no findings. The reactions in the intestinal villi occur rapidly and are short-lived; it is only the consequences that persist for a long time. It is only by making these microscopic processes visible that medicine has taken a significant step forward. Because nothing visible had been found until now, patients had to live with labels such as psychosomatic causes or hypochondria.
Leading Medicine Guide: Do health insurance funds cover the costs of confocal laser endomicroscopy?
Prof. Dr. med. Güldütuna: Unfortunately, this examination has not yet been included in the list of services covered for those with statutory health insurance. If the insurance company does not cover the costs, then we have to proceed cautiously: over a certain period, we eliminate individual foods and then observe the reactions in each case. After all, it is not just the small intestine that reacts allergically these days. Allergies affecting the esophagus have also increased significantly. One possible explanation for this is the changes in food, including the preservatives, colourings, etc.
Leading Medicine Guide: For which symptoms do you use confocal laser endomicroscopy?
Prof. Dr. med. Güldütuna: We also use confocal laser endomicroscopy to examine the esophagus in patients who complain of reflux – commonly known as heartburn. If reflux is left untreated, the lining of the esophagus changes over time. Stomach acid and various enzymes damage it, leading to Barrett’s esophagus, which in turn is a risk factor for esophageal cancer. Cancer develops from the cellular changes, known as dysplasia, in the esophageal lining. Using confocal laser endomicroscopy, we can detect the dysplasia of Barrett’s esophagus – the direct precursors to cancer – at a very early stage; these can then be removed endoscopically without the need for surgery.
Left: Healthy stomach. Right: Reflux disease, in which stomach acid flows into the esophagus © bilderzwerg/AdobeStock
Leading Medicine Guide: What else do Barrett’s patients need to know?
Prof. Dr Güldütuna: Endomicroscopy for the detection of precancerous lesions in Barrett’s esophagus is currently the most common application of endomicroscopy, particularly in the USA. And we have found that, in Barrett’s patients, we also need to examine the small intestine to see if it shows increased permeability. Because that, in turn – as you might have guessed – points to a food intolerance. But if the gut is regularly exposed to substances that trigger an immune response, then it is easy to imagine that the intestinal mucosa suffers. This leads to leaky gut syndrome, which is the term used to describe the damaged, permeable intestinal mucosa that allows substances into the bloodstream that do not belong there and can then cause illness in various ways.
Leading Medicine Guide: What other problems can arise with food intolerances?
Prof. Dr. med. Güldütuna: One condition affecting the esophagus that can be attributed to food allergens is known as eosinophilic oesophagitis. In this condition, which is not actually that rare, foods trigger a very pronounced inflammation of the esophagus, which can lead to serious complications such as narrowing of the esophagus and difficulty swallowing. This immune response, triggered by food allergens, can cause a wide range of conditions, as we already know from celiac disease, a specific type of food allergy to gluten. In this condition, not only the gut but also the skin, liver and other organs can be affected; if the diet is not followed, there may even be a more than 100-fold increased risk of gastrointestinal tumors. Just how ill food intolerances can make people – this is what science has been investigating for several years now and is continually gaining new insights.
Leading Medicine Guide: At your gastroenterology clinic in Frankfurt, you perform confocal laser endomicroscopy. Is this a very complex procedure?
Prof. Dr Güldütuna: There aren’t many centers in Germany yet that offer this examination. It is a complex procedure that requires a great deal of experience. And it’s not enough just to carry out the examination; you also need to be able to provide the patient with appropriate advice and support afterward. I work with a high-resolution endoscope and a microscopy probe that provides up to 1,000-fold magnification. This allows us to see the villi or epithelial cells magnified to a very large size. They stand side by side, almost like soldiers; it looks like the fingers of a glove. To be able to see anything in the laser light, we have previously injected the patient with the contrast agent fluorescein. We then apply small amounts of solution containing various foods to the intestinal mucosa one after the other. If, for example, the patient cannot tolerate wheat, we see quite astonishing images: the intestinal villi spread apart, the mucosa becomes permeable, and in the event of a severe reaction, the epithelial cells even break off. Although they can regenerate, if inflammatory processes are also present, they no longer recover; they break down. If a strong reaction occurs immediately upon the first food solution, we cannot continue testing.
Leading Medicine Guide: What is your current focus in research?
Prof. Dr. med. Güldütuna: A great many patients with food intolerances and allergies come to my gastroenterology clinic in Frankfurt am Main. Using our test results, we are in the process of compiling our own reliable statistics on the subject. I am familiar with practically all studies in this field, both national and international. Because I am confronted with so many enquiries on the subject every day – particularly from young people – I would like to make greater use of the internet for public education in future. I can see that there is an enormous need here, and I can certainly contribute a great deal with my specialist knowledge.
Professor Güldütuna, thank you very much for the interesting conversation and the insight into the progress being made on a topic that affects many of us. Anyone wishing to contact our expert directly can do so via his profile page on the Leading Medicine Guide.
