I often get asked by patients about food allergies because after they eat certain things they just feel AWFUL! And I make sure to do a thorough workup because many different types of food reactions exist and can be food allergies (immunologic) or nonimmunologic (see chart below). I test for food allergies because of the concept of gastrointestinal anaphylaxis. “Gastrointestinal anaphylaxis” is when GI symptoms arise from a food allergy. Usually food allergies cause other organ symptoms (itching, flushing) but also may be the only manifestations of an allergic reaction to food.
adapted from uptodate.com
Food-induced anaphylactic reactions occur when food allergens cross the oral or gut mucosal barrier. After crossing the mucosal barrier, the allergen circulates throughout the body and cross-links food allergen-specific IgE antibodies bound to circulating basophils and tissue mast cells in the skin, gastrointestinal tract, respiratory tract, and/or the cardiovascular system. Activation of these cells results in release of proinflammatory mediators.
IgE-mediated gut symptoms due to eating a food allergen include nausea, vomiting, abdominal pain/colic/cramping, and/or diarrhea The upper GI symptoms (nausea, vomiting, abdominal pain) usually start minutes to 2 hours after eating the food. Lower GI symptoms (diarrhea) starts 2-6 hours after eating the allergen.
Healio highlights from American College of Allergy, Asthma and Immunology Annual Scientific Meeting 2018
A couple interesting facts about food allergens.
●The more you eat, the quicker & more dramatic the symptoms.
●Fatty foods are absorbed slowly, so symptoms may be delayed/prolonged.
●Drinking alcohol leads to quicker & more dramatic symptoms.
●NSAIDS (Ex. Aleve, Motrin, Ibuprofen..) increase gastric permeability to food allergens (Leakygut, folks!).
The non-IgE mediated reactions are mostly in infants including:
●Food protein-induced proctitis/proctocolitis most commonly triggered by cow’s milk in the mother’s diet (Hi Moms! What you eat directly affects your baby especially during breastfeeding!)
●Food protein-induced enterocolitis syndrome (FPIES)- commonly from Cow’s milk and soy in baby formulas
adapted from Children’s Hospital of Philadelphia (CHOP): https://www.chop.edu/pages/breastfeeding-baby-food-allergies
Lets not forget Celiac disease (AKA gluten-sensitive enteropathy) which is an immune-mediated inflammatory disease.
And other mixed IgE and non-IgE mediated reactions include
●Eosinophilic esophagitis (EoE)
● Eosinophilic gastroenteritis
So if you feel bad after eating a certain food— there’s probably a reason for it! Come chat with me about the various food allergy and food reaction testing that can be done!