Researchers found that people with higher levels of a particular antibody in the blood had an increased risk of atherosclerosis, or hardening of the arteries. The antibody is formed in response to a compound in red meat known as alpha-gal (short for galactose-alpha-1,3-galactose).
Alpha-gal is a type of sugar found in red meat as well as some high-fat dairy products. But what’s unusual about alpha-gal allergies is that some people don’t develop the allergy naturally; instead, they develop it only after getting bitten by a lone star tick (Amblyomma americanum).
But not everyone who is sensitive to alpha-gal will develop allergic symptoms after eating red meat; however, they’ll still have measurable levels of the alpha-gal antibody in their blood.
It’s those antibodies, the new study found, that may contribute to a person’s risk of atherosclerosis.
Meat allergies and clogged arteries
In the new study, the researchers looked at 118 people ages 30 to 80 who lived in central Virginia. All of the participants had their blood tested and underwent an intravascular ultrasound — a test that produces detailed images of the lining of the coronary arteries.
After analyzing the participants’ blood samples, the researchers found that 26 percent had detectable antibodies to alpha-gal, indicating a potential sensitivity to red meat. In addition, the artery scans of the people with these antibodies showed they had 30 percent more plaque buildup inside their arteries — a sign of atherosclerosis — than nonsensitized patients.
The new study found that about 20 percent of the people in a tick hotspot had signs in their blood that they had a red meat allergy, but not all of these people developed allergic symptoms after eating red meat, Wilson said. By some estimates, only about 1 percent of people in tick hotspots actually have symptoms of the allergy when they eat red meat, he noted.
Even though the exact mechanism linking the red meat allergy and atherosclerosis is not known, it could be that people with this immune response to red meat could have low levels of chronic inflammation that, over time, could cause problems with their blood vessels, Wilson speculated.
Another limitation of the study, he noted, is that researchers did not know the participant’s dietary habits or what allergies (alpha-gal included) they had.
Wilson said the next steps needed to confirm the findings are to run comparison tests by continuing to gather data from other people in tick hotspots in the southeastern United States, as well as from people in other regions of the country. It would also be helpful to track people over time to find out how many people with alpha-gal antibodies go on to experience heart attacks, compared to those without it, he said.