because immune systems do not typically react to food in healthy intestines, boeckxstaens’ team focused on factors that can compromise this tolerance. recognizing patients often report a gastrointestinal infection — such as food poisoning — as a precursor to their unsettling symptoms, researchers theorized that the specific food present in the gut at the time of infection might make the immune system sensitive to that item.
to test this theory, researchers infected mice with a stomach bug at the same time they gave them ovalbumin, the main protein found in egg whites. once the mice recovered from the infection, they gave them ovalbumin again and found it provoked a similar response from the immune system, causing mast cells to release histamine that prompted intolerance and pain in the digestive system. they also noted this immune response only occurred in the specific area of the intestines that was subject to the infection, suggesting there exists a range of food-related immune diseases.
“at one end of the spectrum, the immune response to a food antigen is very local, as in ibs,” boeckxstaens said. “at the other end of the spectrum is food allergy, comprising a generalized condition of severe mast cell activation, with an impact on breathing, blood pressure and so on.”