The intestinal mucosa protects our body from toxins, pathogens, and undigested food particles. When this barrier becomes compromised, it is referred to as “leaky gut syndrome,” a condition in which unwanted substances enter the bloodstream and can trigger systemic inflammation.
Symptome
In leaky gut, the so-called tight junctions, the cellular connections of the intestinal lining, lose their integrity. As a result, foreign substances and bacterial components such as lipopolysaccharides (LPS) can pass into the bloodstream. This activates the immune system and leads to silent inflammation, also known as low grade inflammation.
The effects are not limited to the digestive tract, where symptoms like bloating, irritable bowel symptoms, or irregular bowel movements may occur. They often extend throughout the entire body, causing fatigue, brain fog, low mood, migraines, skin issues such as eczema or acne, muscle and joint pain, and even autoimmune reactions. Many individuals also report suddenly developing food intolerances, as the immune system begins to overreact to harmless substances.
Causes
Some of the most common triggers include chronic stress, an inflammatory diet high in sugar, gluten, or alcohol, certain medications such as antibiotics or painkillers (NSAIDs), an imbalanced gut microbiome (dysbiosis), and bacterial overgrowth conditions like SIBO. High FODMAP intake can also lead to fermentation and damage to the intestinal lining, especially when the microbiome is already disturbed.
Diagnosis
A leaky gut cannot be measured directly, but there are several meaningful indicators. One key laboratory marker is zonulin, a protein that regulates the permeability of the tight junctions. Elevated zonulin levels in stool or blood are considered a sign of impaired intestinal barrier function.
In addition, stool analyses that test for inflammatory markers such as calprotectin or alpha-1-antitrypsin, as well as secondary mucosal parameters like secretory IgA, histamine, or pH value, can provide valuable insights.
A microbiome analysis complements the picture by identifying whether key protective bacteria such as Faecalibacterium prausnitzii or Akkermansia muciniphila are missing, and whether potentially harmful bacteria like Klebsiella or Clostridium are overrepresented. Reduced microbial diversity can also indicate an imbalanced ecosystem and increased intestinal permeability.
Therapy
Treating leaky gut syndrome requires targeted relief and healing of the intestinal lining, with nutrition playing a central role.
FODMAPs (fermentable short-chain carbohydrates) are often problematic for many individuals. They are poorly absorbed in the small intestine and fermented by bacteria in the large intestine, which can lead to bloating, pain, and diarrhea in those with increased intestinal permeability. A low-FODMAP diet can help alleviate these symptoms. A randomized controlled trial by Halmos et al. (2014, Gastroenterology) showed that this diet not only reduces irritable bowel symptoms but also lowers inflammatory markers, making it beneficial for leaky gut as well. The approach involves temporarily avoiding certain fruits, vegetables, dairy products, legumes, and grains for several weeks, then gradually reintroducing them to identify individual sensitivities.
When the gut is particularly sensitive, for example with severe inflammation, multiple intolerances, or significant bloating, a carnivore diet may be beneficial. This diet consists exclusively of animal-based foods such as meat, fish, eggs, and animal fats. It relieves the intestinal lining from potentially irritating plant compounds such as lectins, oxalates, and certain fibers. An observational study by Peterson et al. (2021, Current Developments in Nutrition) found that this diet led to significant symptom improvement in patients with chronic inflammatory bowel disease. The carnivore diet can be followed for two to six weeks before gradually reintroducing easily digestible vegetables.
In addition, L-glutamine, zinc carnosine, butyrate, omega-3 fatty acids and mucosa-supporting plant substances such as aloe vera or DGL (deglycyrrhizinated licorice) promote healing of the intestinal lining. Well-tolerated probioticsand, later on, gently introduced prebiotics can further support the long-term restoration of a healthy microbiome.
