Alergias al maní y otras leguminosas

Si es alérgico al maní, es posible que haya oído que debe evitar otras leguminosas. ¿Qué debes hacer? Tener una alergia al maní ya es lo suficientemente desafiante. ¿Realmente necesita determinar si los alimentos que consume pueden contener todas las demás legumbres además de los cacahuetes?

Los cacahuetes son una leguminosa

Para entender esta pregunta, es importante hablar sobre el maní y alimentos similares. Los cacahuetes son una leguminosa similar a otras legumbres que crecen bajo tierra como la soya, las lentejas, los guisantes y los frijoles. Son diferentes a las nueces de árbol, como los anacardos, las almendras y las nueces que crecen en los árboles. Intuitivamente, usted pensaría que deberían evitarse otras leguminosas pero las nueces de árbol deberían estar bien, pero esto es falso. Si bien una alergia coexistente a otra leguminosa es similar al riesgo de tener cualquier tipo de alergia alimentaria junto con una alergia al maní, aproximadamente del 25 al 40 por ciento de las personas con alergia al maní también tienen una alergia a la nuez de árbol . Las más comunes son las alergias a las avellanas y las almendras.

Alergia al maní y legumbres

Si se está preguntando si necesita evitar otras legumbres con alergia al maní, la respuesta es “tal vez, pero no menos de lo que deba preocuparse por cualquier alergia a los alimentos que coexista”. De hecho, la mayoría de las personas con alergia al maní pueden comer otras legumbres sin ningún problema (con la excepción del lupino).

Entonces, ¿por qué se les dice a tantas personas que eviten las legumbres? La respuesta es la sensibilización cruzada.

Sensibilización cruzada entre el maní y otras leguminosas en los análisis de sangre

Las pruebas de alergia a menudo muestran un resultado positivo en más de una leguminosa. Este es un resultado de la sensibilización cruzada, lo que significa que las proteínas similares encontradas en las leguminosas se unen a los mismos anticuerpos alérgicos dirigidos contra las proteínas del maní.

Roughly 50 percent of the time if you do a blood test or a skin test for beans in someone with peanut allergies, the result will be positive. Cross-reactivity is also seen with other legumes, in which you will see a reaction. Yet when other legumes are eaten by people who are allergic to peanuts, only five percent react (with the exception of lupin ). This is the same percentage of people you would expect to have another food allergy such as a milk allergy. The only way to know if you have a true allergy to another legume is through an oral food challenge (see below.)

An Exception to the Rule — Lupin

The one exception to the above rule is for lupin. Lupin is a legume commonly ground into flour or eaten whole in European countries. There appears to be a high level of cross-reactivity between peanuts and legumes, since up to 50 percent of people with peanut allergy experience allergic reactions after eating lupine. Some recent studies suggest this number may be less, but what is true is that lupin is becoming much more of a problem for those with food allergies.

It’s uncommon to find lupine in the grocery store in the U.S., but it is fairly common in some European countries. Those who live outside the U.S. or who travel to Europe should keep this in mind. Apparently, the use of lupine (for example, as a substitute for wheat) is becoming more common in the U.S. as well, especially in packaged foods.

What Should You Do About Legumes If You’re Allergic to Peanuts?

If you are told that you have positive allergy tests to multiple legumes, you should check with your doctor before eating any of these foods. While cross-reactivity rates among legumes are low, your doctor will likely perform an oral food challenge to the legume that you are interested in eating to ensure that you are not allergic.

In an oral food challenge, you eat the questionable food, but with medical supervision. Unfortunately, there is not a reliable way to answer this question with a simple blood test or scratch test.

Foods That Are Considered Legumes

You may wonder exactly which foods are considered legumes. Foods classified as legumes (and hence having a protein profile which could cross-react with peanuts) include:

  • Soy and soybeans
  • Beans
  • Peas
  • Lentils
  • Lupin

Coping With Peanut Allergy

Peanut allergy has increased drastically over the past decade and now affects one to two percent of the population. Since this phenomena is occurring in the United States and other developed countries but is not seen in many places in the world, the way in which peanuts are processed may underlie some of this increase. Going with that concept, recent studies looking at boiled peanuts may offer an approach to overcoming the allergy according to some researchers. Certainly, you don’t want to try this without close supervision by your physician, but this research offers hope that breakthroughs in the management of peanut allergy may be nearing. Until then, avoiding peanuts (and other foods which your allergist feels could be dangerous, (including, at times, legumes), is the only surefire approach to escape the serious reactions and even anaphylaxis which may occur with these allergies. Take a moment to review the peanut allergy diet guide to make sure there aren’t any hidden peanut proteins in the foods you eat.