Eating a meat-heavy diet may be harmful if you’re allergic to steak. Many studies have shown that excessive consumption of red meat is bad for your heart.
Now researchers are beginning to pay closer attention to a specific allergy to red meat caused by a tick bite that could play a prominent role in developing heart disease.
What makes you allergic to red meat?
In a new study published this week in the journal Arteriosclerosis, Thrombosis, and Vascular Biology, researchers claim to have for the first time identified this connection.
Galactose-alpha-1,3-galactose, generally referred to as simply alpha-gal, is a form of carbohydrate called oligosaccharide, found in the cells of non-primate mammals including pigs, sheep, and cows – the animals humans eat.
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Alpha-gal was previously identified by doctors as the cause of allergic reactions, including potentially deadly anaphylactic shock in humans. Now they are blaming it for its role in heart disease.
Dr. Satjit Bhusri, cardiologist at Lenox Hill Hospital, New York City who was not directly involved with the study, said:
“This study brings to light that inflammation can cause injury to the inner lining of the heart vessels and lead to heart attacks. Those that are allergic to alpha-Gel have an increased propensity for heart disease, likely due to inflammation, however this is likely not the only underlying factor in those who have heart disease and this allergy.”
The research team conducted intravascular ultrasounds of 118 subjects to observe atheroma, the accumulation of plaque, inside the arteries of the heart. They also tested for the presence of alpha-gal allergy.
Alpha-gal allergy was spotted in roughly one-quarter (26.3 percent) of the participants, and researchers discovered a significant association of atheroma burden and volume in those patients with the alpha-gal allergy.
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Individuals with the allergy had 30 percent more plaque buildup than those who did not, in some cases.
First author Dr. Jeff Wilson, a researcher at the University Of Virginia School Of Medicine said;
“Previous studies have shown that non-specific markers of allergic disease were associated with atherosclerosis, but this never included a specific allergen. Identification of a specific allergen is intriguing because it suggests that dietary avoidance of the specific allergen may be beneficial.”
How a tick bite revealed the red meat allergy
Alpha-gal allergy is a relatively novel discovery and is not always easy to identify.
It was first discovered in 2002 by Dr. Thomas Platts-Mills, also at the University of Virginia, that the allergy was likely from an unexpected source: a breed of tick common to certain areas of the United States known as the lone star tick (Ambylomma americanum). It is mainly found in the Southeastern United States, as well as parts of New York, New Jersey, and New England.
Platts-Mills was exploring why some individuals were having allergic reactions to the cancer drug cetuximab, which contains alpha-gal. He found that those with a history of lone tick bites were inclined to to allergic reactions while using the drug.
It’s still not understood how lone tick bites trigger alpha-gal sensitivity, however they’re recognized as the primary culprit.
When a tick bite causes alpha-gal sensitivity in a human, it changes their immunological response to eating meat. For these individuals, when meat is eaten, the body has an allergic reaction. The body produces immunoglobulin E (IgE) as a response to the perceived threat of alpha-gal entering the body.
This reaction has earlier been observed as the cause of allergy symptoms, such as asthma, stuffy or runny nose, hives, headaches nausea, and sneezing.
In earlier research, it has also been identified as the cause anaphylaxis in otherwise seemingly healthy individuals.
However, unlike most allergies in which symptoms present almost immediately, alpha-gal allergy may not show signs for up to six hours after eating meat. This makes it difficult to identify and treat.
Wilson said; “The best way find out if you are sensitized to alpha-gal is to get the blood test. We currently only recommend it for people who notice allergic symptoms after eating red meat. It is possible for blood test to be used to screen for individuals, mainly those with histories of tick bites and who live where lone star ticks are common, who could be at heightened cardiovascular risk because of the sensitivity.”
The team believe that identifying the association between tick bites, alpha-gal sensitivity, and heart disease could have significant implications for future care. Among those affected by the allergy, specialized care and guidelines may need to be developed.