Can food allergies affect heart health? Antibodies to certain allergens, particularly cow's milk, can significantly increase the risk of cardiovascular mortality, a study has revealed.

Food allergies occur when the immune system reacts unfavorably to certain types of food, mistaking them for being harmful. To tackle the perceived threat from the allergen, the immune system releases an antibody called immunoglobulin E (IgE).

People with food sensitivities can develop hives, wheezing, itching, swelling and digestive issues such as abdominal pain, nausea, vomiting and diarrhea after exposure to the allergen. In some people, food allergies can lead to anaphylaxis, a life-threatening reaction.

In people who do not have symptoms of food allergy, food-specific antibodies or IgE were considered clinically irrelevant. However, in the latest study, published in The Journal of Allergy and Clinical Immunology, researchers found a link between IgE and increased risk of cardiovascular mortality.

"People who had an antibody called IgE to foods that they regularly eat seemed to be at increased risk for dying from heart disease. We were surprised by these findings because it is very common to have IgE in foods (about 15% of American adults have IgE in 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," said study lead author Corinne Keet, from the UNC Department of Pediatrics.

The strongest link with cardiovascular death was noticed in people who had the antibodies but continued to consume the food regularly. While the maximum risk was associated with cow's milk, other allergens such as peanuts and shrimp were also dangerous.

"What we looked at here was the presence of IgE antibodies to food that were detected in blood samples. We don't think most of these subjects actually had an overt food allergy, thus our story is more about an otherwise silent immune response to food. While these responses may not be strong enough to cause acute allergic reactions to food, they might nonetheless cause inflammation and over time lead to problems like heart disease," said researcher Jeffrey Wilson, from the University of Virginia School of Medicine.

The research team reviewed 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). They measured the participant's total and specific IgE to allergens, including cow's milk, egg, peanut, shrimp, alpha-gal, dust mite and timothy grass. During the study, 285 people died from cardiovascular causes.

Participants with IgE antibodies to at least one food, particularly those sensitive to milk, were associated with a significantly higher risk of cardiovascular death. Further analysis showed significant risk among those who routinely ate peanuts and shrimp even when they had sensitivities.

"The findings do not conclusively prove that food antibodies are causing the increased risk, but the work builds on prior studies connecting allergic inflammation and heart disease," the news release said.

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