Meat allergies may be much more common than previously thought and may even induce potentially fatal anaphylaxis in some people, according to a study conducted by researchers from the University of Virginia and presented at the annual meeting of the American Academy of Allergy, Asthma & Immunology in New Orleans.
The researchers tested three groups of people across the U.S. Southeast with a history of recurrent anaphylaxis without known cause for an immune reaction to alpha-gal, a kind of sugar found in mammal meat.
Although most allergic reactions are caused by proteins, scientists recently discovered that alpha-gal is responsible for anaphylactic reactions to cetuximab, a cancer drug. Further studies revealed that people who experience immune responses to alpha-gal also develop allergic symptoms within three to six hours of eating mammalian meat.
Alpha-gal is not found in the flesh of bird or fish.
The researchers found that between 20 and 50 percent of participants tested positive for allergy to alpha-gal. Overall, 25 of 60 participants (42 percent) showed signs of meat allergy.
Although doctors have known of meat allergies for some time, they have previously presumed them to be uncommon. The new study suggests that as many as half of all unexplained food allergies may be attributed to meat, however.
“This would make me personally think about including these foods in my differential diagnosis,” said Michael Pistiner of Children’s Hospital Boston, who was not involved in the study.
Meat allergies may be harder to detect than other food allergies because it takes the body three to six hours to produce a reaction to alpha-gal. They also tend to develop in adults rather than children, in contrast to most food allergies.
Although the study only looked at patients suffering the most severe reactions, co-author Scott. P. Commins noted that alpha-gal allergies probably occur in a wide variety of severities, just like other allergies.