Where is alpha-Gal found?
Alpha-Gal reactions are typically caused by ingestion of red meat (e.g., beef, pork, lamb, rabbit, horse, goat, venison, bear); organ meats (e.g., intestines, hearts, livers, kidneys), and other products made from mammals.2,4 Additional foods that may pose a risk for those with alpha-Gal syndrome include soup-stock cubes, gravy packages, flavor ingredients in prepackaged products, meat extracts used in flavoring, dairy products (e.g., milk, cheese, yogurt, butter), canned tuna (which can be contaminated by dolphin or whale), chicken or fish cooked on a grill contaminated with red meat, pork-gut casings for sausages, pork fat (used for cooking and often found in pastries and venison burgers), and suet.4,8 Meanwhile, fish, reptiles, and birds typically don’t contain alpha-Gal.1
Gelatin, which is normally derived from the collagen in the skin or hooves of large mammals, may also be problematic. In fact, most patients allergic to red meat are sensitized to gelatin, which is the main ingredient in items such as jelly babies (aka gummies), marshmallows, and jello.4,10 While rare, case reports show reactions to topical or oral gelatin can occur from items such as shampoo, collagen implants, catgut sutures, and collagen-derived contact lenses. Additionally, gelatin may pose a risk as a binding agent in tablets, capsules, suppositories, and confectionaries.10 Those with antibodies related to alpha-Gal syndrome also can have reactions to the cancer treatment cetuximab.2
Nonfood sources that may cause a reaction include some forms of monoclonal antibodies, vaccines, gelatin used as a plasma expander, enzyme replacements, bovine or porcine heart valves, antivenom, heparin (i.e., a glycosaminoglycan derived from pig intestines), and stearic acid and/or magnesium stearate (e.g., various tablets including acetaminophen, oxycodone, lisinopril, oxycontin).4