Dr.med.scient. Verena Stiegelbauer, MSc. BSc.
Leaky Gut – intestines full of “holes”
The Leaky Gut Syndrome is always associated with other conditions like autoimmune diseases, for example. Scientists have spent a lot of time figuring out what role a Leaky Gut plays in the development of diseases, and how it is influenced by the microbiome.
The intestinal barrier as a protective layer
The intestines have an enormous surface area with countless weak points for pathogenic microorganisms to attack. The intestinal barrier protects and defends our body from these microorganisms. This barrier is made out of healthy intestinal flora in the colon, the intestinal mucosa and the immune system that sits within the intestines. The intestinal flora drives out harmful germs, and certain bacteria can produce substances that inhibit the growth of foreign bacteria. Our intestinal bacteria are also responsible for regulating the protective function of the intestinal mucosa and the intestinal immune system. The intestinal mucosa forms a thick and dense layer, and, as the name suggests, is surrounded by a layer of mucous that prevents harmful germs from entering the body.
How do negative changes to the intestinal flora affect the intestinal barrier?
An altered intestinal flora is known as dysbiosis and is associated with abnormal and inflammatory symptoms. The causes of a dysbiosis vary but here are some of the most common:
- Medicine (e.g. antibiotics)
- Overgrowth of pathogenic germs
- Interactions with the immune, nerve and hormonal systems
An impaired intestinal flora usually makes itself known through the following symptoms: Belching, flatulence, foul-smelling faeces and intestinal cramps. The main problem is an imbalance between healthy and harmful intestinal bacteria. Pathogenic bacteria propagate massively with the right environmental changes and drive out healthy bacteria. This can quickly lead to inflammations and, subsequently, an intestine “full of holes” (Leaky Gut Syndrome).
What is a Leaky Gut (= “an intestine full of holes”)?
A “Leaky Gut Syndrome” is an increased permeability of the intestinal wall, which usually acts as an indispensable barrier between our bodies and the outside world. In this case, the layer of mucous on the intestinal surface changes and many bacteria die. Afterwards, special stress and inflammatory messenger substances are produced which destroy the intestinal cell layer below. Instead of simply leaving the body through defecation, all the toxins that we ingest through our food can now pass unhindered into the bloodstream and nerve pathways below. This subsequently leads to changes and diseases. Besides a balanced microbial colonisation of the intestines and the adequate production of mucous and proteins for the immune system, an intact intestinal mucosa is imperative for protection against pathogens and preventing unwanted substances from passing through the intestinal wall.
The aftermath of Leaky Gut Syndrome
As a consequence of the Leaky Gut Syndrome, the barrier function of the intestinal mucosa is impaired, and an excess of unwanted substances enter the bloodstream. These can include, as mentioned above, pathogenic germs, harmful substances or even large molecules from food (see figure 2). As a result, an inadequate immune response towards these substances and germs is triggered in the intestines, which can lead to the development of allergic reactions towards these substances and molecules. Above all, inflammations of the intestinal mucosa and food intolerances can arise. Based on these changes, chronic inflammatory processes can turn into autoimmune diseases such as type 1 diabetes or multiple sclerosis. Nowadays, modern lab tests (that revolutionised the diagnosis) can clearly show to what degree a reduced intestinal flora is responsible for disturbances and diseases: This list spans from allergies and chronic fatigue syndrome to chronic inflammatory bowel diseases such as Crohn’s disease or ulcerative colitis, depression, irritable bowel syndrome and even colon cancer.
How is a Leaky Gut diagnosed?
One method to diagnose a Leaky Gut Syndrome is the so-called lactulose-mannitol-test. Patients have to drink a lactulose-mannitol-solution, and after a certain incubation time, the patients’ urine is examined for traces of the substance. If large traces of this substance are found in the urine, then an impaired intestinal barrier is very likely. Another possibility to diagnose a Leaky Gut would be the zonulin test. This test recognises zonulin which is released by intestinal cells after certain triggers and is increased in a permeable intestinal barrier. Using serum samples, lab workers can test how much zonulin is in the blood with increased levels hinting towards Leaky Gut Syndrome. The inflammatory marker alpha-1-antitrypsin can be measured with stool tests. This protein is mainly produced within the liver and is responsible for the regulation of inflammatory reactions. If the intestinal barrier has a higher permeability, alpha-1-antitrypsin can pass into the intestines and, ultimately, land in the stool.