Soya Allergy


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Soya allergies tend to be one of the more common food allergies. In some parts of the world, such as Japan, as many as 1 in 8 people can be affected with it. In most cases, an allergy to soya first becomes apparent in young babies and children. Like peanuts, soya is a member of the legume family. Some people find that if they have a soya allergy they are also allergic to other legumes such as lentils, beans and peas.

P34 in Soya - The Culprit

Sensitivity to soya can vary from one individual to another. Of the 15 different proteins found in soya, nearly 75% of those affected are all allergic to the same one. It has been named P34, and researchers are constantly trying to find new ways in which to ‘silence’ this protein via genetic manipulation. Studies show that blood tested from people who were given soya that did not contain the active protein P34 did not suffer an allergic reaction.

Reaction to a Soya Alllergy

Symptoms vary according to sensitivity. In minor allergic reactions, mild respiratory problems, bowel upset and a rash might occur. In more severe reactions, restriction of the airways, increased stress on the heart, severe bowel upset and hives can all occur, possibly leading to anaphylaxis. In such cases where individuals know they have a severe allergy to soya they will carry with them an emergency dose of adrenaline just in case they accidentally ingest soya or a soya containing product. Other symptoms can include itchy eyes and nose, swelling of the throat, watery bowels, a fever, fatigue, vomiting, decrease in blood pressure, and wheezing.

Foods Containing Soya

Soya can be found in a whole range of products, some of which might not be an obvious choice for containing it. Listed below are some of the more common products in which it can be found.

  • Soy & Worcestershire Sauce
  • Soy Butter
  • Soy Flour
  • Soy Milk
  • Soybeans
  • Soy Sprouts
  • Tofu
  • Infant Cereals & Infant Formulas
  • Baked Foods

There are some instances where soya proteins may not cause an allergic reaction. The fermentation process in which some soy food products go through tend to break down the offending protein in such a way that the immune system no longer views it as a harmful substance. Example include:

  • Tempeh, a staple source of protein in Indonesia is one such food.
  • Shoyu and tamari are another source of fermented soya and are used as soy sauces.
  • Miso. This is a seasoning used mostly in Japanese cooking and is made by fermenting rice and barley with soybeans, a specific type of fungus and some salt.

As with all food allergies, checking food labels is of paramount importance. Because soya is found not only in the form of beans and soy sauce, it is vital to check for soy additives and proteins in order to ensure a soya free diet.


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