For people with an uncommon sensitivity to a particular carbohydrate in red meat, the risk of heart disease is elevated when red meat is consumed. From the National Heart, Lung, and Blood Institute and the University of Virginia Health System, scientists show for the first time the connection between this red meat allergy and the buildup of plaque in the arteries.
Findings of this new study are pulling the focus away from saturated fat, high levels of which have before caused scientists to link together red meat and increased risk of heart disease. Now scientists are concerned about sensitivity to a red meat allergen that leads to plaque buildup in the coronary arteries, a condition called atherosclerosis that leads to heart disease.
Plaques are made up of cholesterol, cellular waste products, calcium, and fibrin, and their buildup causes arteries to become thicker, restricting blood flow. Atherosclerosis can lead to coronary artery disease, angina, carotid artery disease, peripheral artery disease, and chronic kidney disease.
“Allergy to red meat may be an underrecognized factor in heart disease," explained study leader Coleen McNamara, MD. "These preliminary findings underscore the need for further clinical studies in larger populations from diverse geographic regions and additional laboratory work."
The allergen is a carbohydrate called galactose-α-1,3-galactose (alpha-Gal). The allergy is restricted to red meat because alpha-Gal exists only in most non-primate mammalian cell membranes. A bite from the Lone Star tick causes sensitization to alpha-Gal, a phenomenon that has a monumental effect on the geographic distribution of red meat allergies. The more common the Lone Star tick is, the higher the prevalence of alpha-Gal allergies. Places like the Southeastern U.S. and Long Island, New York, are especially known for the tick and the allergy.
Scientists aren’t sure exactly how many people in the United States have a true red meat allergy, but they guess it’s around one percent of the population. A much larger amount of people (20 percent approximately) produce antibodies to alpha-Gal without actually showing symptoms of a “true” allergy.
The present study to diagnose the relationship between alpha-Gal allergies and heart disease was with 118 adult participants from Virginia. Researchers conducted a blood sample analysis looking for antibodies that targeted alpha-Gal. They found such antibodies - a type of immunoglobulin E (IgE) in 26 percent of participants. Imaging showed that plaque buildup was 30 percent higher in these participants. This specific type of IgE is specific to the alpha-Gal allergen.
The present study was published in the journal Arteriosclerosis, Thrombosis, and Vascular Biology.
Sources: American Heart Association, Popular Science, UNC Chapel Hill Department of Medicine, NIH/National Heart, Lung, and Blood Institute