Can Proteins in Plant-Based Food Cause Allergic Reactions?

Scientists examined whether people with allergies to peanuts, soybeans, and other legumes were also allergic to legumes found in plant-based protein products.

Plant-based food products often contain legume-based proteins from beans, lentils, nuts, and seeds.

But because peanuts and soy are also legumes, people with peanut and soybean allergies may wonder if consuming a plant-based protein product containing other legumes could cause a food allergy reaction due to cross-reactivity.

Recently, researchers from the University Medical Center Utrecht aimed to investigate this question. Their study, published on March 16 in Frontiers in Allergy, may have found evidence that although co-sensitization to other legumes is common, actual allergic reactions are less likely.

The scientist aimed to determine how often participants would experience co-sensitization and co-allergy between legumes. To do this, they divided participants with legume allergies into six groups according to their allergy — peanuts, soybeans, lupines, green peas, beans, and lentils.

The team tested the participants in each group for reaction-inducing immunoglobulin E (IgE) antibodies against other legumes.

After the testing concluded, the scientists found that co-sensitization to other legumes occurred in all groups, and one-quarter of participants experienced co-sensitization to all other legumes.

Among people with a bean allergy, nearly all had sensitization to other legume groups. However, those with peanut or soybean allergies were not likely to experience sensitization to other legumes.

Still, in participants with confirmed allergies to several legumes, only a small number experienced clinical symptoms.

Although people with peanut and soybean allergies were unlikely to have sensitivities to green peas, lupines, lentils, and beans, participants who had documented green pea, lupine, lentil, and bean allergies were more likely to be sensitive to peanuts and soybeans.

Overall, the study showed that many of the co-sensitizations were not clinically relevant. For example, in the peanut and soybean-allergic participants, the scientists rarely observed a co-allergy with other legumes.

This is likely due to the fact that not all people with co-sensitivities to other foods will experience symptoms. Still, if a person has sensitivities to a specific food, they may react when exposed to that food in the future.

"Legumes are an attractive sustainable protein source, but allergic reactions in the already legume-allergic population cannot be excluded as antibodies in the blood of legume-allergic patients frequently react to different legumes," says senior author Thuy-My Le, in a news release.

"However, this reaction does not always lead to a clinically relevant food allergy," Le adds.

Still, people diagnosed with legume food allergies should consider talking with their allergist before adding plant-based proteins into their diets to ensure they can safely consume legume-based products.