Celiac disease and food allergy: roles of undigested food peptides

Protein digestion is the breakdown mechanical, chemical and enzymatic proteins contained in foods that are reduced to smaller units. The digestion encloses several steps, including the mechanical extraction of the proteins from the food, the denaturation of proteins and the hydrolysis of peptide bonds. The protein must be digested and grind into amino acids or di- and tripeptides before absorption can take place, although sometimes they can be absorbed peptides larger. There are foods peptides resistant to digestion such as gliadin and lactalbumin respectively involved in celiac disease and in cow's milk allergy. Coeliac disease (CD) is a systemic immune-mediated disorder elicited by gluten in genetically susceptible individuals.A common feature of gluten proteins is the presence of a high level of proline and glutamine residues, which renders gluten highly resistant to proteolytic degradation in the gastrointestinal tract. Consequently, the released peptides can cross the gut epithelial barrier and reach the lamina propria of the intestinal mucosa, triggering two immunological pathways: the adaptive and the innate immune responses. Cow's milk allergy is an IgE-mediated allergy very common, affecting 2-5% of children under 1 year of life. Requires the complete exclusion of milk from the diet of children. The resistance to proteases of the entire gastrointestinal tract is a prerequisite of peptides derived from milk, , in particular the ?-lactalbumin, is resistant to proteolytic digestion and therefore probably involved in the onset of disease. The present study has been focused on the role of undigested food peptides in these two disease.