Study: People with Dairy Sensitivities May Have a Higher Risk of Cardiovascular Disease

People who have trouble digesting dairy may have an increased risk of cardiovascular disease.

Scientists have identified asthma and eczema as risk factors for cardiovascular disease, however, until now, food sensitives haven’t made the list.

New research, published earlier this month in The Journal of Allergy and Clinical Immunology, found that a food sensitivity or allergy to dairy may increase the risk of cardiovascular disease.

“We found that having IgE to milk was associated with an increased risk of cardiovascular death in two cohorts,” Corrine Keet, MD, PhD, first author of the paper and professor of pediatrics at the University of North Carolina at Chapel Hill School of Medicine, told Health. “This has not previously been reported.”

The research team analyzed two longitudinal studies, one of 4,414 adults who were tracked for 14 years and one of 960 adults who were tracked for 19 years, and found that people who produced immunoglobulin E (IgE) antibodies when they consumed cow’s milk and other foods were at significantly increased risk of cardiovascular death.

This remained the case even when risk factors for heart disease were considered, such as smoking, high blood pressure, and diabetes.

But, the study didn’t prove that dairy allergies cause cardiovascular events to occur—it just showed an increased risk.

“The data are from observational studies and show correlation,” Keet said. “We have not established causation.”

Here’s how dairy allergies may impact cardiovascular health, and what people with dairy sensitivities can do to avoid cardiovascular risk.

How Food Sensitivity Can Affect the Heart

According to Keet, allergists have known for a long time that allergic reactions can involve the cardiovascular system.

“But because we found that the association between IgE and cardiovascular disease was strongest for those who report regularly eating the food allergen, we believe that this is probably not related to the kind of acute reactions that are involved in food allergy that we diagnose,” she said. 

Allergic reactions involve the immune system’s response, releasing substances like
histamines and cytokines.

“While these substances are critical in defending against pathogens, chronic or systemic inflammation is also a recognized factor in the development and progression of cardiovascular diseases, including atherosclerosis (narrowing and hardening of the arteries),” Rigved Tadwalkar, MD, a consultative cardiologist at the Pacific Heart Institute Providence Saint John’s Medical Foundation, told Health.

In the context of Keet’s research, Tadwalker explained the presence of IgE antibodies to common food allergens is associated with an elevated risk of cardiovascular mortality.

“Although the precise mechanism remains unclear, it is plausible that the chronic inflammatory response triggered by allergic reactions contributes to the inflammatory processes underlying heart disease,” he said.

Further research is needed to uncover the specific pathways through which allergic reactions might impact cardiovascular health.

Tadwalker explained that Keet’s findings challenge the conventional understanding of allergies as isolated systems and hint at systemic implications extending to cardiovascular health.

“From a cardiology perspective, it is of importance to recognize this evolving area of study, emphasizing the need for further research to fully understand the underlying mechanisms and the potential clinical implications for people with allergies,” he said.

The Difference Between Food Sensitivity and Food Allergy

Understanding the difference between food sensitivity and food allergies is helpful.

IgE are antibodies produced by the immune system when a person is exposed to something they are sensitive or allergic to. These antibodies release chemicals in the body that can cause an allergic reaction in the nose, lungs, throat, or skin. 

However, Keet noted that while about 15% of American adults have IgE to common food allergens, not all people who produce IgE to foods experience an allergic reaction.

In the new analysis, the research team did not know if study participants had clinical food allergies, but Keet said it can be assumed that most participants probably weren’t severely allergic to the foods in question.

When researchers excluded people who avoided the food, the association between the food and cardiovascular death strengthened, implying that the findings are most relevant to people who have not been diagnosed with food allergy.

Currently, Keet explained that allergists’ standard thinking is that even if people have IgE to foods, it’s okay to eat those foods if they don’t experience allergic symptoms.

“I think we are left with more questions than answers from this work,” Keet said, “but the findings do raise the question about whether food allergy pathways are important in heart disease.”

How People With Allergies Can Boost Heart Health

Because researchers still can’t distinguish correlation from causation, they are not recommending that everyone get food testing or make changes to their doctor’s advice regarding food-specific IgE.

“[Current] advice is to eat the foods if there are not symptoms consistent with food allergy,” Keet said. “More research needs to be done to understand whether and how food-specific IgE has a causal relationship with cardiovascular disease.”

Tadwalkar recommends that people with food sensitivities or allergies prioritize their overall heart health through lifestyle measures, including:   

• Adopting a heart-healthy diet
• Incorporating a balance of fruits, vegetables, whole grains, and lean proteins
• Engaging in regular physical activity for cardiovascular fitness and weight management 

For people with pre-existing cardiovascular disease, Tadwalkar recommends intensive management of the condition.

“Considering the potential broader health implications, monitoring and managing allergies effectively should be better integrated logistically into routine healthcare,” he said. “Until we learn more, a holistic approach to health, considering both allergy management and cardiovascular health, is most advisable for individuals with known allergies.”