It's every carnivore's nightmare — imagine suddenly finding out that you're unable to eat any form of red meat without a severe allergic reaction. This unfortunate condition is not only possible, it's a growing phenomenon.
The alpha-gal allergy, also known as Mammalian Meat Allergy (MMA), is an immune system reaction to the carbohydrate galactose-alpha-1,3-galactose. This molecule is found in the cells of almost all mammals, including beef, pork, and lamb meat. In rare cases, traces of alpha-gal can also be present in dairy products, such as milk, cheese, and ice cream. Individuals with the alpha-gal allergy may experience severe itching, hives, upset stomach, trouble breathing, dangerous drop in blood pressure, and even life-threatening anaphylaxis after consuming red meat or dairy containing alpha-gal.
This allergy is also unusual and especially dangerous due to its delayed onset. Unlike most food allergies, which present symptoms 5 to 30 minutes after exposure, symptoms of the alpha-gal allergy generally appear 3 to 6 hours after red meat consumption. Dean Metcalfe, M.D., of the National Institute of Allergy and Infectious Diseases (NIAID) said, “this unusually long time gap between a meal and an allergic reaction is probably a big reason that alpha-gal allergies are often initially misdiagnosed.”
Now, you might be thinking that you're in the clear because you weren't born with this allergy, but that's not the case. The red meat allergy can be caused by tick bites — specifically those from the lone star tick in the United States, the castor bean tick in Europe, or the paralysis tick in Australia. The tick bite transmits alpha-gal into the victim's skin through its saliva, causing the victim's immune system to overreact with a release of antibodies that lead to the allergy.
The lone star tick is present throughout the eastern half of the United States, from Maine to Texas. However, this range is expanding, leading to an increase in cases of red meat allergy. Dr. Scott Commins, an allergist and associate professor of medicine, told NPR, “We're confident the number is over 5,000 [cases], and that's in the U.S. alone.”
There is no known cure for red meat allergy, but there are some tidbits of good news. First, it doesn't require you to become a full vegetarian, since poultry and fish will not trigger the reaction. Second, although there's no guarantee, it may diminish or disappear over time provided that the patient doesn't get bitten again by another Lone Star tick.