Many people make the choice to avoid red meat - some because they don't like the idea of eating animals, some because they prefer how they feel when they eliminate it from their diet, some because of environmental reasons.
For a very small percentage of people, however, the choice to abstain from meat is made for them. They find they are allergic to red meat.
The reason for the meat allergy is thought to be due to a tick bite. In North America, the lone star ticks, specifically. The lone star tick is easily identified. it has a white dot on its back. It is primarily found in the eastern part of the United States, in the South most frequently, but has been identified in other areas of the country. Other instances of the allergy have been found around the world, the result of bites from other types of ticks who carry alpha-gal molecules.
When researchers at the University of Virginia first started studying the problem 13 years ago, the reactions were linked to an allergy to alpha-gal, a molecular sugar found in red meat from mammals. Interestingly besides meat and meat products, reactions can also be caused by other products that are derived from mammals, such as the gelatin that is found in gummy bears, medications such as heparin and thyroid hormone, bioprosthetics such as porcine heart valves, and unlabeled "natural flavorings".
Allergies to meat can occur at any time in life. The symptoms are quite the same as other food allergies - stomach cramps, diarrhea, vomiting, shortness of breath, hives, swelling of the tongue or lips, and indigestion.
Instead of a quick onset as with many other food allergies, the symptoms of an allergy to meat may take three to six hours from eating until onset. Unlike most food allergies the problem is caused by the transmission of a sugar (or a carbohydrate) rather than a protein.
How is this allergy diagnosed? Because this allergy is still relatively new and not very prevalent, it takes a provider who has some knowledge not only of food allergies but of the possibility of this rare allergy. Only about 34,000 have been diagnosed with the condition, though this low number is probably partially due to the lack of knowledge of the condition.
While taking the medical history, the provider will first ask questions about the onset of symptoms when red meat was eaten, and if there has been exposure to ticks and possible tick bites. Two tests can also be used. A blood test may confirm the presence of alpha-gel antibodies. The other test is the typical skin prick test, done to detect allergies. Small amounts of red meat are exposed to the skin to see if a reaction develops.
While it is generally agreed that the tick is responsible for the allergy, exactly how it is transmitted isn't totally clear. Research continues on this subject. The prevailing thought, however, is that the issue is due to alpha-gal sugar in the saliva. The sugar is transmitted in the bite and impacts the immune system. Thus the name for the allergy is Alpha-gal syndrome.
The good news for those diagnosed with the allergy and who love meat is that without additional tick exposure the symptoms of Alpha-gal syndrome can go away. Some people diagnosed have been able to eat meat again within one to two years after the tick bite. In the meantime, Alpha-gal has not been found in poultry and seafood, so they can continue to be part of the person's diet if desired.