Common meat-free proteins may trigger allergic reactions in some patients with a legume allergy

Many people, keen to reduce their meat consumption, turn to alternatives made from legumes, which are packed with protein, vitamins and fiber. But allergies to legumes such as soybeans or peanuts are common and serious. Are patients with an allergy to certain legumes at risk for lean protein made from legumes even if they contain different legumes? Dr. Mark Smits and a team of scientists at the University Medical Center Utrecht set out to investigate.

said Dr. Thuy Mye Lee, senior author of the study published in the journal limits in sensitivity. “Increased consumption of legumes may lead to an increase in the number of sensitivities to these foods. Moreover, these new legumes may trigger allergy complaints in patients who are already allergic to legumes. Therefore, we investigated how often sensitivities and sensitivities to different legumes occur in people with These patients.”

sensitivity than any other name

People develop food allergies when their immune systems mistake food proteins for the threat and produce immunoglobulin E (IgE) antibodies. Sensitive individuals can, upon re-exposure to the same food, develop allergy symptoms. Patients who react to one food may also react to another: this is a common allergy. Co-allergy accompanies a common allergy, in which patients produce IgE antibodies against several foods. Co-sensitization may result from cross-reactivity, in which IgE antibodies bind to proteins from multiple foods because the proteins share similar structures.

Cosensitivity can lead to a diagnosis of a joint allergy, but it doesn’t always: It is possible for a person to be jointly sensitive to a food, but not have a reaction when they eat it. So, do patients with a legume allergy react to other legumes?

Smits and colleagues recruited patients with legume allergy from the allergy clinic at the University Medical Center Utrecht and divided them into six groups according to sensitivity: peanuts, soybeans, green peas, lupins, lentils and beans. All patients had validated sensitivity by oral food challenge or a positive IgE test along with a history of reactions. Each batch was tested for a different IgE antibody against other legumes.

We showed that a large number of patients produced antibodies to more than one legume. However, clinical data has shown that only a small fraction of these patients develop actual symptoms.”

Dr. Katie Verhoex, second author of the study

High incidence of cross-sensitivity among legumes, but not always cross-sensitivity

All six groups of patients showed a combined sensitivity to additional legumes, and almost a quarter of patients were sensitized to all legumes. Almost all patients in the bean allergy group were sensitized to other legumes. Patients who were allergic to green peas, lupins, or lentils were also more likely to be allergic to other legumes, while patients diagnosed with peanut or soybean allergies were not.

The team also looked at which of these patients had a documented common allergy to several legumes. A high rate of co-sensitization has been associated with clinical symptoms in a relatively small number of patients. In patients allergic to peanuts and soybeans, cross-allergies to green peas, lupins, lentils, and beans were uncommon, but patients allergic to this second group of legumes were likely to have a joint sensitivity to peanuts or soybeans. Patients with a peanut allergy often have a common sensitivity to soy, and vice versa. Peanut co-sensitivity was associated with clinically relevant co-allergies in almost all other legume groups. However, the team cautioned that it would be necessary to expand the study to a larger group and confirm co-sensitization with oral food challenges to determine the clinical relevance of this co-sensitization in practice.

“Because legumes are an attractive and sustainable source of protein, but allergic reactions in the legume-allergic population cannot be ruled out because antibodies in the blood of allergy sufferers from legumes frequently react to different legumes,” Lee said. “However, this reaction does not always result in a clinically relevant food allergy. The introduction of new foods into the market must be accompanied by an appropriate assessment of the risk of developing a (new) food allergy.”