CHAPEL HILL, N.C. — Unnoticed sensitivities to common food allergens like cow’s milk and peanuts may be a key and underemphasized cause of heart disease, a new study warns. Moreover, researchers from the University of North Carolina School of Medicine stress that this increased risk for cardiovascular death includes people without obvious food allergies.
This latest project, which consisted of two studies, reveals increasing levels of an antibody called immunoglobin (IgE) in response to cow’s milk is associated with cardiovascular-related death.
This work, led by Corinne Keet, M.D., Ph.D., a pediatric allergy and immunology professor in the UNC Department of Pediatrics, documents that people who produce IgE antibodies to cow’s milk and other foods are at a much higher risk of cardiovascular death. This held true even after accounting for traditional risk factors for heart disease, including smoking, high blood pressure, and diabetes. The strongest connection was to cow’s milk, but IgE production to other allergens, such as peanuts and shrimp, was also significant among those eating these foods.
Researchers say these concerning findings represent the first time ever that IgE antibodies to common foods have been linked to an increased risk of cardiovascular mortality. Importantly, this study does not conclusively prove that food antibodies are directly causing the increased risk. However, this work does build on earlier projects that found associations between allergic inflammation and heart disease.
“People who had an antibody called IgE to foods that they regularly eat seemed to be at increased risk for dying from heart disease,” Dr. Keet says in a media release. “We were surprised by these findings because it is very common to have IgE to foods (about 15% of American adults have IgE to common food allergens), and most people don’t have any symptoms when they eat the food. As allergists, our thinking has been that it is not important if people have IgE to foods, as long as they don’t have symptoms when they eat the food.”
Funded by the National Institute of Allergy and Infectious Disease, this research used two methods to examine the association between IgE sensitization to foods and cardiovascular death.
First, the team used data from 4,414 adults who participated in The National Health and Examination Survey (NHANES) and 960 participants in the Wake Forest site of the Multi-Ethnic Study of Atherosclerosis (MESA) cohort. Participants were enrolled in MESA from 2000 to 2002 and followed for up to 19 years. Those in NHANES, meanwhile, were enrolled between 2005 and 2006, with researchers tracking mortality data for up to 14 years.
They measured total and specific IgE to cow’s milk, egg, peanut, shrimp, and a panel of aeroallergens for the NHANES group. IgE to cow’s milk, alpha-gal, peanut, dust mite, and timothy grass, on the other hand, were measured for the MESA group. In NHANES, the study recorded 229 cardiovascular deaths, and 960 deaths from MESA. Notably, milk sensitization had an association across both NHANES & MESA. Researchers also saw that food sensitization to shrimp and peanuts appeared to be an additional heart disease risk factor.
It is vital to note that these associations are related to food sensitization rather than clinical allergy. Although the research team did not have access to information regarding clinical food allergy across either group, they assumed individuals who reported regularly eating a food allergen on food frequency surveys were not experiencing any food allergy symptoms. Thus, the results that showed how associations strengthened when researchers excluded those who avoided the food indicate those findings in particular are likely the most relevant for those who have not been diagnosed with food allergy.
Dr. Keet adds that the findings raise many questions regarding whether or not these apparently non-allergic individuals may deal with any long-term consequences from consuming foods to which they may be sensitive.
The project states that besides two recent reports linking IgE to the unusual carbohydrate allergen alpha-gal to coronary artery disease, cardiovascular disease had never been previously identified as a long-term complication of food sensitization. Regardless, there is now substantial evidence for the importance of allergic-type immune pathways when it comes to normal cardiac physiology and heart disease.
“More research needs to be done about how sensitization to common food allergens is related to cardiovascular disease,” Keet concludes. “While this study provides good evidence of an association between sensitization to these allergens and death from cardiovascular disease, there is much work to be done to understand if this is a causal relationship.”
The study is published in the Journal of Allergy and Clinical Immunology.
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