Leaky Gut Syndrome

Letzte Aktualisierung am 9. December 2023 von Dr. Michael Zechmann-Khreis

Especially in connection with “intestinal flora analyses” and IgG4 food intolerance tests, we often hear about leaky gut syndrome. In this article, we explain what is behind this and whether such a leaky gut really exists. We also have a blog post on the topic of “leaky gut”. There you can find out everything you need to know in a nutshell.
The term “leaky gut” comes from the English-language specialist literature and means “permeable bowel” or, in German-speaking specialist jargon, “intestinal permeability”. This is different from the alternative medical “leaky gut” postulated in German-speaking countries.

Leaky gut: to blame for everything?

The idea behind the alternative medicine concept is that the gut loses its barrier function due to various influences such as parasites, infections, stress, sugar, gluten or medication. Harmful substances such as microbes, toxins or food components therefore penetrate the body. The immune defense subsequently triggers various diseases and symptoms. These include allergies, obesity, cancer, diabetes, hypothyroidism, hyperthyroidism, joint pain, autism, chronic fatigue or even food intolerances and allergies.

Fact or profiteering?

At first glance, this may sound understandable, albeit somewhat surprising. Because whenever a single cause is supposed to trigger so many different diseases, caution is advised. And indeed, “leaky gut syndrome” in this form is pure fantasy. Most providers who promote this disease usually also offer diagnostic procedures, books, preparations, online courses and, of course, treatments. Unfortunately, there are also many self-proclaimed experts in social media groups who give advice without medical training and often spread false information.

The problem with leaky gut syndrome is as follows: Various medically correct facts about leaky gut from the specialist literature and physiological processes that are not yet scientifically understood are interwoven into new theories. People then like to “prove” these theories with references to scientific studies in which the term “leaky gut syndrome” appears. On closer inspection, however, these studies say something completely different or have nothing to do with the topic at all. With a few healing stories spread over the internet, the theory is credible enough for many patients and you can start doing business.

Leaky Gut: A search for clues

Before we can answer the question of whether the postulated leaky gut syndrome exists, we need to take a closer look at the gut and its microbiome.

Structure of the intestinal wall

So-called epithelial tissues act as barriers in living organisms. At the same time, however, selective transport also takes place through these tissues. Living beings are not separate from their environment, but are in exchange with it. Our uppermost skin layer is such an epithelial tissue, but so is our intestine.

The epithelial cells of the intestine form a very large and complex surface area, as they have to absorb vital nutrients from food. At the same time, they must keep out harmful substances. They have developed unique and highly complex functions for this purpose.

Put simply, the intestinal wall consists of epithelial tissue and a very special “water layer”, many proteins and muscles. The cell structures of the intestinal wall are not static; the intestine is not a garden hose, but extremely variable. They are constantly changing. The intestinal barrier must be thought of as a flexible barrier that has to deal with countless different substances and stimuli. And yes, the intestine is permeable. It has to be, otherwise it could not accomplish its task of absorbing nutrients.

Permeability of the intestine

This permeability of the intestine is highly dependent on the section of the intestine. The small intestine (in which fewer microbes live) is more permeable than the large intestine (in which there are many microbes). The bacteria (actually microbiota) interact with a layer of the intestinal wall, which itself actually consists of two layers: a thin inner layer and a thick outer layer. The bacteria proliferate in the outer layer, which is in contact with the food pulp. They are rarely found in the interior. This region in the intestine forms the bacteria’s living room, so to speak, and at the same time acts as a barrier between them and us. This prevents microbes, whether pathogenic or friendly, from adhering to the epithelium or even entering the body.

Damage to the balance

Now it can happen that this homeostasis, i.e. the balance, is disturbed. Genetic factors or external factors such as medication, a permanently unhealthy diet or serious illnesses reduce this barrier, throwing the balance out of kilter. It is also assumed that the types of bacteria present have an influence on the barrier. Complex physiological processes loosen the so-called “tight junctions”, i.e. the connections between the cells. Pathogenic germs and smaller molecules can then enter the body in isolated cases because the barrier is missing and the intercellular spaces no longer function properly. Here they trigger inflammation or immune responses, for example. In science, this condition is called “leaky gut”, sometimes also “leaky gut syndrome” or simply increased intestinal permeability. Incidentally, the reaction to invading bacteria is the body’s normal reaction to invading foreign substances and not yet a “syndrome”.

What questions are still open, what answers do we know?

Status: December 2023

• We do not know whether leaky gut (the scientifically based type) and dysbiosis are the cause or consequence of autoimmune diseases.
• The comparison made in the alternative medicine concept with a garden hose full of holes is false and misleading.
• The intestinal microbiome (i.e. the intestinal flora) has a major influence on our health. We do not yet know the exact details. This means that interventions involving intestinal flora analyses and the addition of individual bacterial strains are not recommended from today’s perspective. According to the recommendations of the specialist associations, a healthy wholefood diet and sufficient exercise are better.
• There should be a balance in the intestine. This can best be maintained and achieved through a healthy lifestyle and a wholefood diet.
• The balance can be disturbed by serious illnesses or intestinal surgery.
• In irritable bowel syndrome, chronic inflammatory bowel disease and coeliac disease, there are indeed problems with the intestinal barrier or a component of the intestinal barrier. Scientists call this “leaky gut” or increased intestinal permeability.
• Increased intestinal permeability is not necessarily harmful. Our body is well prepared for these eventualities. Only a combination of factors, e.g. obesity, stress, dysbiosis and other problems, then lead to symptoms or health problems.
• The “holes” between the epithelial cells (which are completely normal) are far too small, even in the worst case, to allow larger molecules, let alone food components, to pass through. Today we know that certain bacteria can penetrate this loosened barrier.

Does leaky gut syndrome exist or not?

Defining “leaky gut syndrome” as an independent syndrome that is caused, for example, by our modern diet and is responsible for a large number of lifestyle diseases and can be diagnosed using simple blood tests is certainly not correct. There is no scientific evidence for this and the postulated model behind it is full of medical and physiological misconceptions. The huge financial interest in the sale of “cures” and diagnostic procedures for leaky gut syndrome is high and should remind every patient to remain critical.
We now know that there are a variety of reasons, whether obesity, insulin resistance, stress or other factors, that lead to problems in the gut or are the result of problems in the gut. As this is very complex and we do not yet know enough about it, a good holistic medical assessment is important.

There is no question that a healthy and well-functioning gut is important for our well-being. However, patients with digestive problems should undergo proper diagnostics before diagnosing themselves with an alternative medical syndrome that does not exist in this form.

Sources

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First version: May 2019, new findings since then.