Food allergy and the gastrointestinal tract.

Objective: Adverse reactions to food resulting in gastrointestinal symptoms are common in the general population. Although only a minority of individuals complaining of such symptoms have immune-mediated reactions to food (food allergy), gastrointestinal food allergies do exist in both children and adults. This review provides an update on the pathogenesis and clinical management of food allergy manifesting in the gut, emphasizing recent developments in the field.

Results: Recent studies have broadened our understanding of the innate gastrointestinal defense systems and the role of the gut flora for protection against allergy. These findings support the hygiene theory in which microbial challenge in early life is thought to protect against the development of allergic disease. New insights into the regulation of mast cells and eosinophils, their homing to the intestine, and their interaction with the specific immune system and the enteric nervous system have been given. In parallel, the molecular structure of major food allergens is being unraveled, and new therapies that focus largely on modulating the immune response to food antigens have been developed.

Conclusions: These new findings have important implications for the diagnosis and management of food allergies. The availability of recombinant allergens will improve methods to diagnose and treat food allergy, and genetic engineering will allow future therapies such as vaccination against food allergy. Emerging knowledge of the role of the gut flora in mucosal immunity will enhance strategies to prevent and treat food allergy using probiotics such as Lactobacillus GG. Such new approaches will extend existing options for managing food allergy and preventing anaphylaxis.