Soy allergy checklist: From soy sauce to tofu, what to avoid

The core avoidance principle for soy allergy is that not only dominant soy products such as tofu, soy milk, yuba, natto, dried tofu, and tofu must be completely avoided, but also all processed foods and seasoning products containing soy protein and soy-derived ingredients must be paid attention to. People with severe allergies should even avoid foods that are cross-contaminated with soy products.

A while ago, I accompanied a friend to the allergy department for a review. She had urticaria after eating braised pork ribs at home last week. She was puzzled and finally realized that the light soy sauce in the braised pork ribs was not changed. It was fermented soybeans. She only remembered not to eat tofu before and did not include soy sauce in soy products. Many people who have just been diagnosed with soy allergy have this misunderstanding and think that they should avoid only those that taste like beans. In fact, soy sauce, bean paste, soybean paste, miso, fermented bean curd, tempeh, and even many salad dressings and Thousand Island dressings are added with soybeans to thicken and enhance the flavor in our daily condiments. If you are not paying attention, it is easy to get infected.

When I was sorting out the ingredients list for my best friend's baby with allergies, I also discovered that many foods that seemed to have nothing to do with soy also contained soy ingredients. For example, soy protein isolate was added to children's sausages to improve the chewy texture. Soy powder was added to many crispy fried noodles and pre-mixed powders to increase crispiness. Soy protein powder was even added to milk caps and smoothie bases in many milk tea shops to enhance the texture. Last time, the baby took a sip of the milk cap without asking in advance, and his face was swollen for two days. There are also soy lecithin, soy dietary fiber, soy isoflavones, and hydrolyzed vegetable protein derived from soy that are often seen in the ingredient list. They are all high-risk ingredients for allergy, so just avoid them if you see them.

Of course, there is no unified conclusion in the academic community on the allergenicity of fermented soy products. Studies have shown that the degradation rate of allergenic proteins in soy products that have been deeply fermented for more than 3 months can reach more than 90%. Some people with mild to moderate allergies may not have allergic reactions if they eat a small amount. I also have friends who are allergic to soy. A friend said that he had no reaction at all after eating ten-year-old soy sauce, but there are also authoritative cases showing that even highly fermented soy products may induce severe allergies. So this kind of thing really varies from person to person. Don’t try it rashly. If you really want to try it, you must first see a doctor for an allergen challenge test and listen to professional judgment before making a decision.

By the way, there is another soybean oil that everyone often asks about. Refined soybean oil has completely removed the allergenic soybean protein during the processing. Most people with soybean allergies can tolerate it. However, cold-pressed and crude-pressed soybean oil should be avoided because of the remaining unprocessed protein components. If you are not sure, it is safer to choose other vegetable oils. Anyway, the people I have come into contact with who are allergic to soy have basically found out their tolerance boundaries after stepping on invisible pits several times. It is better to look through the ingredient list twice when buying things, and to tell the merchants about their allergies in advance when going out to eat, which is much better than suffering an allergic attack.