Abstract

In terms of nutrient acquisition, the small intestine is the most important organ of the human body. Small intestinal permeability represents the ability of any substance to pass through the epithelium, even in the absence of the corresponding transporter protein. Since the permeability of the small intestine is dynamic, largely dependent on the microbiome and shapes the symptoms of several diseases, it is important to be able to determine it reliably and to interpret the obtained results based on scienctific knowledge. For this purpose, mostly in vivo methods are used, for example, active tests based on the administration of saccharides. As an alternative, it is possible to determine the level of biomarkers in the blood, urine or faeces. For example, the levels of calprotectin, zonulin, citrulline and claudin-3 are used, but their disadvantage is still low specificity, low evidence basis or inaccuracies in the tests used.