Living with a soybean allergy often means making some changes to what you eat and which medications you carry with you. Making these small lifestyle adjustments can help keep you safe and healthy.

Part of these changes involve understanding the allergy and what to expect around it. Here’s what you need to know about soy and what a soybean allergy means for your daily life.

What You Need To Know About a Soy Allergy

Soy is short for soybean, which is part of the legume family, alongside other types of beans like black, pinto, and navy beans. Many foods contain soy, particularly plant-based items, because it can have a meat-like texture when it’s processed. Soy is also common in some types of Asian cuisine.

About 0.4 percent of babies in the United States live with a soy allergy. Most of them will outgrow it, though some will remain allergic throughout their lives. Unlike some other allergies, like fish and shellfish, most soy allergies show up in infancy or early childhood. Some people who are allergic to soy are also allergic to peanuts. People with a soy allergy may also have allergies to tree nuts, sesame, eggs, and milk. They may also have an allergic reaction to other legumes, though this is less common than sensitivity to these other allergens.

Being allergic to soy means your body is particularly sensitive to certain proteins found in that plant. These proteins trigger an immune system reaction that mistakenly tells your body to defend itself from an attack. The symptoms you experience are caused by this response.

Symptoms of a Soy Allergy

People with a soy allergy can have symptoms that range from mild to severe. The type of symptom you or your loved one has — and how severe it is — can change over time. Your symptoms may get worse over time, and it’s not always possible to predict how the body will react to an allergen. Because each reaction can be different, it’s important to take a soy allergy seriously every time.

Symptoms of a soy allergy may include:

• Hives
• Itching, including around the mouth or on the face
• Eczema breakouts
• Stomach issues, like nausea, vomiting, diarrhea, or stomach cramps
• A persistent cough
• Tightness or swelling in the throat, mouth, or tongue

A severe allergic reaction to soy can cause anaphylaxis. This is a whole-body reaction that can be life-threatening if it isn’t treated right away. Symptoms of anaphylaxis include:

• A rapid heart rate
• Dizziness
• Confusion
• Low and/or rapidly dropping blood pressure
• Trouble breathing
• Losing consciousness

Most of the time, your healthcare provider will prescribe an epinephrine auto-injector. You’ll use this if you have symptoms of anaphylaxis, because it can quickly stop a serious allergic reaction. Your provider will show you how to use it and make sure you feel comfortable doing so. You should always carry two epinephrine auto-injectors with you. Some anaphylactic responses require more than one dose of epinephrine.

Even if you use your epinephrine and start to feel better, you should always follow up with a visit to the emergency room to make sure your allergic reaction doesn’t come back.

Some allergists may also recommend other medications to help manage symptoms of food allergies. They’ll explain when to use those medicines and when to use your epinephrine. If you’re ever unsure, it’s safer to use epinephrine than to risk severe anaphylaxis.

Diagnosing a Soy Allergy

A soy allergy is usually diagnosed by an allergist, a doctor who specializes in allergies. They'll ask about your medical history and what happens when you’re exposed to soy. Then, they may order allergy tests to help confirm the diagnosis.

One option is a skin prick test. In this test, a small amount of soy is placed on your skin, and the skin is lightly pricked to see if there’s a reaction.

Another option is a blood test, which checks your blood for antibodies that react to soy. This test is done in the doctor’s office. You’ll eat small, increasing amounts of soy while the healthcare team watches closely for symptoms. This is done in a medical setting so they can provide immediate care if a serious reaction happens.

Once the results come in, your allergist will evaluate them to see if you have a soy allergy. If you do, they’ll make sure you understand how to avoid soy and what to do if you’re exposed to it.

5 Foods To Avoid With a Soy Allergy

The best way to avoid an allergic reaction is to keep soy out of your diet completely. Soy is one of the top nine allergens in the United States, so products that contain it must list it on the label. It should show up in the ingredients list.

Many packaged foods also include a separate allergen statement near the ingredients that clearly lists major allergens, such as soy. Some ingredients that contain soy will have “soy” in their name, but others won’t. The list below can help you figure out which foods and ingredients are generally safe for a person living with a soy allergy.

1. Many Dairy Alternatives

Soy is a common ingredient in plant-based dairy products. These may include:

• Soy milk
• Soy cheese
• Soy ice cream
• Soy yogurt

Anytime you eat a dairy alternative (a product that is similar to dairy but doesn’t include milk), check to see if it contains soy.

2. Asian Foods

Soy ingredients are in many foods that originate in Asia, especially, but not only, in Japan. Be on the lookout for:

• Miso
• Natto
• Shoyu
• Okara
• Tofu
• Soy sauce
• Tamari
• Tempeh
• Hoisin

It’s also a good idea to avoid buffets that offer these as food options. Even safe foods can get contaminated with soy (called cross-contamination) if someone uses the same spoon with a soy product and a nonsoy product, for example.

3. Foods Including Parts of the Soybean Itself

Sometimes, people eat the soybean or parts of it directly. The most common of these foods include:

• Edamame
• Soy nuts
• Soy sprouts

Avoid these items to stay healthy and avoid any allergic interactions.

Soy oil comes with a special consideration. You may see “soy oil” listed on ingredient labels. The good news is that most people with a soy allergy can safely eat highly refined soy oil. That’s because when making highly refined soy oil, the allergy-causing proteins are removed. However, you should avoid cold-pressed or gourmet soy oils, as these still contain proteins that can cause a reaction.

4. Processed Soy Foods

Soy is processed in a lot of different ways, then used as a food additive. The most common versions of this include:

• Soy albumin
• Soy flour
• Soy fiber
• Soy grits
• Soybean curd
• Soybean granules
• Soy protein (comes in isolate, hydrolyzed, and concentrated forms)
• Textured vegetable protein (TVP)

If you read labels and see any of these ingredients, that food isn’t safe for people who are allergic to soy. On the other hand, soy lecithin can be safe for many people who have a soy allergy.

5. Protein-Fortified and Packaged Foods

Soy can also show up in packaged foods, especially items marketed as “high protein” (like protein bars, shakes, meal replacements, and some meat substitutes). These products don’t always contain soy, but they often use soy-based ingredients to boost protein or improve texture.

Check labels for soy-based protein ingredients, such as soy protein isolate, soy protein concentrate, TVP, and hydrolyzed soy protein. Also be cautious with vague ingredient terms that may sometimes be soy-derived (for example, “hydrolyzed vegetable protein” or “natural flavors”), since sourcing can vary by brand.

You may find soy in a lot of unexpected foods. These can include:

• Baked goods and snack foods
• Canned soups, broths, and sauces
• Cereals
• Processed meats (some sausages and deli meats)
• Infant formula (some types)

Additionally, vitamin E (tocopherols) can be sourced from soybean oil or other oils, so ask your doctor if it is safe for you.

Because soy can be used in many processed foods, read every label every time — and if you’re unsure, it’s safest not to eat it.

Keep in mind that soy can also be found in nonfood products. This includes medicines, soaps, moisturizers, and other personal care products. If you’re particularly sensitive to soy, you may need to avoid these as well.

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What food is the hardest for you to avoid with a soybean allergy? Let others know in the comments below.