Food allergies may be linked to an increased risk of cardiovascular disease, research shows

Sensitivity to common food allergens such as dairy and peanuts could be a major and previously unappreciated cause of heart disease, new research suggests – and the increased risk of cardiovascular disease extends to people without obvious food allergies.

That increased risk could equal or even exceed the risks of smoking, diabetes and rheumatoid arthritis, the researchers report.

UVA Health scientists and their collaborators looked at thousands of adults over time and found that people who produced antibodies in response to dairy and other foods were at increased risk for cardiovascular disease. This was true even when traditional risk factors for heart disease, such as smoking, high blood pressure and diabetes, were taken into account. The strongest association was for cow’s milk, but other allergens such as peanuts and shrimp were also significant.

The disturbing finding represents the first time that ‘IgE’ antibodies against common foods have been linked to an increased risk of cardiovascular death, the researchers report. The findings do not conclusively prove that food antibodies cause the increased risk, but the work builds on previous studies that linked allergic inflammation and heart disease.

About 15% of adults produce IgE antibodies in response to cow’s milk, peanuts and other foods. Although these antibodies cause some people to develop severe food allergies, many adults who produce these antibodies do not have an overt food allergy. The new research found that the strongest link with cardiovascular death was in people who had the antibodies but continued to consume the food regularly – suggesting they did not have a severe food allergy.

“What we were looking at here was the presence of IgE antibodies to food that were detected in blood samples,” says researcher Jeffrey Wilson, MD, PhD, an allergy and immunology expert at the University of Virginia School of Medicine. “We don’t think most of these subjects actually had a food allergy. So our story is more about an otherwise silent immune response to food. While these reactions may not be strong enough to cause acute allergic reactions to food, they can still cause inflammation and over time lead to problems such as heart disease.”

Unexpected findings about food allergy

The researchers were inspired to explore the possibility that common food allergies could harm the heart after members of the UVA team previously linked an unusual form of food allergy, spread by ticks, to heart disease. That allergy, first identified by Thomas Platts-Mills, MD, PhD of UVA, is transmitted by the bite of the lone star tick, found across much of the country.

The allergy – commonly incorrectly called the ‘red meat allergy’ – makes people sensitive to a certain sugar, alpha-gal, found in mammalian meat. The symptomatic form of the allergy, known as “alphagal syndrome,” can cause hives, stomach upset and breathing difficulties – even potentially fatal anaphylaxis – three to eight hours after affected people eat beef or pork. (Poultry and fish don’t contain the sugar, so won’t cause a reaction.)

To see whether other food allergies might affect the heart, a team including Wilson, Platts-Mills and collaborators at UVA, as well as Corinne Keet, MD, PhD, of the University of North Carolina, reviewed data collected from 5,374 participants in the National Health and Examination Survey (NHANES) and the Wake Forest site of the Multi-Ethnic Study of Atherosclerosis (MESA). Of those people, 285 had died from cardiovascular causes.

Among NHANES participants, IgE antibodies against at least one food were associated with a significantly higher risk of cardiovascular death, the researchers found. This was especially true for people who are sensitive to milk, a finding that also held true among the MESA participants. Additional analysis also identified peanut and shrimp sensitization as significant risk factors for cardiovascular death in individuals who ate them routinely.

“We previously noted a link between allergic antibodies to the alpha-gal red meat allergen and heart disease,” Wilson explained. “That finding is supported by a larger study in Australia, but the current paper suggests that a link between allergic antibodies to food allergens and heart disease is not limited to alpha-gal. In some ways this is a surprising finding. On the other hand, we are not aware of anyone having looked before.”

Allergies and the heart

Although this is the first time that allergic antibodies to common foods have been linked to cardiovascular death, other allergic conditions – such as asthma and the itchy rash known as eczema or atopic dermatitis – have previously been identified as risk factors for cardiovascular disease.

The researchers speculate that allergic antibodies to food may affect the heart by leading to the activation of specialized cells called mast cells. Mast cells in the skin and intestines are known to contribute to classic allergic reactions, but they are also found in cardiac blood vessels and tissue. Continued activation of mast cells can cause inflammation, contributing to the formation of harmful plaques that can cause heart attacks or other heart damage, the researchers think.

However, the scientists emphasize that this is not yet certain. It is possible that other genetic or environmental factors play a role. It’s even possible that cardiovascular disease could increase the risk of food sensitization – meaning heart disease could increase the risk of food allergies, rather than the other way around – although the new results suggest this is unlikely.

The researchers call for further research to better understand the implications of their findings before recommending changes in the way doctors treat or manage food allergies.

This work raises the possibility that a blood test could help provide personalized information about a heart-healthy diet in the future. Although before that can be recommended, we still have a lot of work to do to understand these findings.”

Jeffrey Wilson, allergy and immunology expert, University of Virginia School of Medicine

Findings published

The researchers published their findings in the leading allergy journal, the Journal of Allergy and Clinical Immunology. The research team consisted of Keet, Emily McGowan, David Jacobs, Wendy Post, Nathan Richards, Lisa Workman, Platts-Mills, Ani Manichaikul and Wilson. Wilson and Platts-Mills have received support from Thermo-Fisher/Phadia; a full list of the authors’ disclosures is included in the article.

The research was supported by the National Institute of Allergy and Infectious Disease of the National Institutes of Health under grants 5U01AI125290, R37-AI20565, and R21AI151497; and by an AAAAI Foundation Faculty Development Award. A list of the funders of the MESA trial is available in the paper.