Food Allergies: New Challenges of Our Civilization

People need to eat and digest food, and if they encounter a food allergy it is a real problem. Moreover, some people have a lifelong sensitization to certain products with the threat of anaphylaxis. This chapter considers different aspects of food allergies, allergenicity of dietary allergens, the significance of the gut microbiota and intestinal epithelium integrity, detailed processes of food sensitization, clinical phenotypes and management of food allergies, and, finally, mechanisms of oral tolerance. Fortunately, the gastrointestinal tract possesses robust tolerogenic mechanisms, in particular, the beneficial gut microbiota, as well as the autonomous enteric nervous system, which taken together with the gut immune cells and molecules may be called the enteric neuroimmune system (ENIS). The dual-allergen exposure hypothesis postulates that early oral exposure to food allergens induces tolerance, whereas exposure at non-gastrointestinal sites results in food sensitization and allergy development. In addition, a series of food allergic episodes does not look like a typical atopic disease and is a known exception to the rule conceived by evolution. However, the prevalence of food allergies is continuously growing, including severe cases, and it is a paradoxical problem in the face of evolution. This challenge is inherent to our civilization and will be resolved, thanks to new knowledge and technologies