Coleen McNamara, MD
A sensitivity to galactose-α-1,3-galactose (alpha-gal), an allergen found in red meat, has been linked to the buildup of plaque and increased atheroma burden, especially in those who are 65 years of age and older.
The new data, while also representing a novel and possibly modifiable risk factor for coronary atherosclerosis, represent yet another new finding regarding the relatively unknown alpha-gal, which was recently identified as an expanding problem in medicine. The allergen, only identified in recent years, is estimated to impact roughly 1% of the US population, however, it may affect as much as 20% of the population in certain areas, especially where the Lone Star tick is prevalent—its bite a known sensitizer of alpha-gal.
“This novel finding from a small group of subjects from Virginia raises the intriguing possibility that allergy to red meat may be an underrecognized factor in heart disease,” said study leader Coleen McNamara, MD, a professor of medicine in the Cardiovascular Research Center of the University of Virginia Health System, in Charlottesville, in a statement. “These preliminary findings underscore the need for further clinical studies in larger populations from diverse geographic regions and additional laboratory work.”
McNamara and colleagues analyzed blood samples from 118 subjects who had presented for cardiac catheterization and had undergone an intravascular ultrasound, seeking the blood marker immunoglobulin (IgE) specific to alpha-gal.
IgE for alpha-gal was identified in 26% of these patients, and after assessing plaque with imaging techniques, it was revealed that the plaque buildup was 30% higher in the patients sensitized to alpha-gal compared to those that were not (P = .02). As these plaques tend to be less structurally stable, their likelihood of resulting in myocardial infarction and stroke are higher.
“Because α-Gal sensitization relates to an environmental exposure that could be a risk factor for early-onset coronary artery disease (ie, tick bites), we age-stratified the cohort,” the authors wrote. This arrangement by age led to the finding that those aged 65 years and older were at a higher risk for atheroma burden (P <.001), and that the plaques in the sensitized group had less stability.
IgE to inhalants and peanuts were assayed as well and found to not be associated with coronary artery disease. While strongly associated with one another, the strength of the association between total IgE and alpha-gal-specific IgE was less so than the relationship between the ladder and atheroma burden.
When adjusted for sex, the prevalence of diabetes, hypertension, statin use, and total IgE the association was statistically significant (regression coefficient, 12.2; standard error, 5.2; P =.02)
“[This] work provides a potential new approach or target for preventing or treating heart disease in a subgroup of people who are sensitized to red meat,” said Ahmed Hasan, MD, PhD, a medical officer and program director in National Heart, Lung, and Blood Institute’s Atherothrombosis & Coronary Artery Disease Branch.
The authors noted that the evidence for this link between red meat allergens and coronary artery disease is introductory, and thus more information will need to be identified. Currently, the only treatment of red meat allergy is the strict avoidance of red meats.
The study, “IgE to the Mammalian Oligosaccharide Galactose-α-1,3-Galactose Is Associated With Increased Atheroma Volume and Plaques With Unstable Characteristics,” was published in Arteriosclerosis, Thrombosis, and Vascular Biology. It was funded by the National Institutes of Health.