July 9, 2018Cardiology
The number of people with red meat allergies in the United States is unclear, but it has been estimated that it may be as high as 1% of the population in some areas. The number of people who develop blood antibodies to the red meat allergen without having full-blown symptoms is much higher -- as much as 20% of the population in some areas.
Only in recent years has the main allergen in red meat, galactose-a-1,3-galactose, or alpha-Gal, a type of complex sugar, been identified.. Interestingly, the Lone Star tick sensitizes people to this allergen when it bites them. That is why red meat allergies tend to be more common where these ticks are more prevalent, such as the Southeastern United States, but also extending to other areas, including Long Island, New York. It has been suspected for some time that allergens can trigger certain immunological changes that might be associated with plaque buildup and artery blockages, but no one had identified a specific substance that is responsible for this effect. Now, according to an article published in Arteriosclerosis, Thrombosis, and Vascular Biology (ATVB; 14 June 2018), results suggest a link of sensitivity to alpha-Gal to the buildup of plaque in the arteries of the heart. While high saturated fat levels in red meat have long been known to contribute to heart disease for people in general, this new finding suggests that a subgroup of the population may be at heightened risk for a different reason - a food allergen.
In the current study, it was shown for the first time that a specific blood marker for red meat allergy was associated with higher levels of arterial plaque, or fatty deposits on the inner lining of the arteries. The blood marker they identified is a type of antibody (immunoglobulin or IgE) that is specific to the alpha-Gal allergen. To identify this blood marker, the authors analyzed blood samples from 118 adults and detected antibodies to alpha-Gal in 26% of the samples, indicating sensitivity to red meat. Using an imaging procedure, it was found that the quantity of plaque was 30% higher in the alpha-Gal sensitized patients than in the non-sensitized patients. These plaques, a hallmark of atherosclerosis (hardening of the arteries), also tended to be more structurally unstable, which means that they have an increased likelihood of causing heart attack and stroke.
According to the authors, that since the evidence for a link between red meat allergens and coronary artery disease is still preliminary, they plan to conduct detailed animal and human studies to confirm their initial findings. Currently, the only treatment for red meat allergy once it is diagnosed is strict avoidance of red meat.