A major part of the immune system is situated in the intestine, and the gut is also home to trillions of microbes. These gut microbes play an important role in regulating the immune system. Therefore, it makes sense that good health and inner protection starts with promoting the beneficial gut microbiota. The consumption of prebiotics such as chicory root fibres leads to increases in beneficial bacteria in the gut such as the bifidobacteria. These bacteria ultimately promote an increase in short chain fatty acids (SCFAs) and other metabolites as a result of their fermentation. This helps maintain a favourable environment for a balanced microbiota and reduce the growth of pathogens. Furthermore, breakdown products and metabolites are absorbed into the bloodstream, through which they will reach and positively affect other parts of the immune system and other organs. 

Scientific studies - There is scientific evidence for a supportive effect of chicory root fibres on the immunological/inner defence system, as is confirmed in scientific reviews.  

An overview of scientific studies on this topic.