It has come to light that many people in the United States are allergic to red meat. A new study suggests that the immune response that it triggers may increase heart disease risk.
That red meat can be bad for our health is not news; red meat is the nutritional pariah of the 21st century, and not without good reason.
Primarily, the levels of saturated fat in red meat are known to contribute to heart disease.
However, according to a recent study, some people are more at risk than others.
Perhaps surprisingly, this increased risk is due to a food allergen. The latest findings are published in the journal Arteriosclerosis, Thrombosis, and Vascular Biology.
It was only relatively recently that the main allergen in red meat — a complex sugar called galactose-alpha-1,3-galactose (alpha-gal) — was identified.
Allergies and heart disease
For some time now, scientists have believed that allergies, in general, may set off an immunological chain reaction that leads to atherosclerosis, or a buildup of fatty plaque in the arteries that hardens over time, narrowing the blood vessels. However, the mechanisms that underpin this process are not understood.
In the new study, researchers at the University of Virginia Health System in Charlottesville wanted to dig deeper. So, they devised an experiment to investigate whether individuals with red meat allergies might be more susceptible to atherosclerosis and, if so, why.
To see whether or not there was a link, they assessed the blood samples of 118 Virginia residents for an antibody specific to alpha-gal.
The marker was found in 26 percent of the sampled participants. As they expected, people who were allergic to red meat were more likely to have increased levels of arterial plaques.
In fact, participants who were sensitive to alpha-gal had 30 percent more arterial plaque than those who did not mount an immune response.
Additionally, the plaques in allergic individuals were more unstable, making them more likely to cause heart attack and stroke.
"This novel finding from a small group of subjects from Virginia raises the intriguing possibility that allergy to red meat may be an under-recognized factor in heart disease."
Study leader Dr. Colleen McNamara
Who is affected?
It is still not clear exactly how many people are allergic to red meat, but it is thought to be roughly 1 percent of the population. However, as much as 20 percent of certain populations may produce a lower level response to the allergen.
Interestingly, a bite from the Lone Star tick sensitizes people to alpha-gal, thereby making red meat allergies more common in the Southeastern states, where this tick resides.
At this stage, the link between red meat allergies and atherosclerosis is not set in stone; the team plans to continue investigating, using larger groups of participants. Dr. McNamara notes, "These preliminary findings underscore the need for further clinical studies in larger populations from diverse geographic regions and additional laboratory work."