Soybean allergy tends to be more common in babies and young children, with many outgrowing it as they age (1). It is estimated that about 0.4% of infants in the US are allergic to soy.
Soybeans are legumes, just like beans, peas, lentils and peanuts. Up to 88% of people with soy allergies are also allergic or significantly sensitized to peanuts, although the reverse isn’t true (2). People with soy allergies are more likely to be allergic to major allergens like peanuts, tree nuts, egg, milk, and sesame, than to other legumes.
This post may contain affiliate links and when you click on the links I may earn a small commission at no charge to you. As an Amazon affiliate, I earn a commission from qualifying purchases.
How to Introduce Soy
While most of the research on allergen introduction has been done on peanuts, there is no research indicating harm in introducing other allergens using similar guidelines. For most children, we recommend to introduce food allergens “early and often.”
As with other allergens, introduce soy as the only new food that day. If you are looking for a more comprehensive guide to introducing allergens, check out my Allergy Introduction Handbook.
- Soy infant formula (not recommended for preterm infants)
- Smashed edamame
- Soy yogurt
- Tofu scramble
- Silken tofu in a smoothie
The gold standard for the diagnosis of a food allergy is an oral challenge. While scary, it’s actually an easy test to perform: if the child eats the allergen, do they consistently produce a reaction? If so, they are allergic. Then, to confirm a diagnosis, a doctor may use a blood test or skin prick test. A medical professional should always make the diagnosis. A self-diagnosis can lead to unnecessary restriction.
How to Avoid Soy
Avoidance can be difficult, because soy is used in many processed foods. It’s very important to always check food labels. Companies must list soy clearly on the ingredients list in plain language or under the label in a statement that reads “Contains soy.” Most people will not react to soy lecithin, but speak with your allergist about your unique situation.
Some babies with soy allergies will have a cross-reaction to milk proteins in formulas as well. They may benefit from a hypoallergenic formula. This is something that should be discussed with a physician or a pediatric dietitian familiar with your child.
Places to Check
Always ask about ingredients in foods that you did not make yourself. When eating at a restaurant, there is always a risk of cross-contact, so it is important to make it very clear that there is an allergy.
Soy is commonly used in Asian cuisine, such as Chinese, Indian, Indonesian, Thai and Vietnamese. There is always a risk of cross contact, even if you order a soy free item.
You can also sometimes find soy in vegetable gum, starch or broth, baked goods, canned soups, canned meats, cereals, cookies, crackers, snack bars, dairy products, infant formula, processed meats, sauces, sausages, and tempeh. It can also be in household products such as medication, lotions, soaps, moisturizers, and other personal care products.
Other Names for Soy
These terms mean that soy may be present:
- Cold-pressed, expelled or extruded soy oil*
- Soy protein
- Soy sauce
- Textured vegetable protein (TVP)
What about soybean oil?
Soybean oil does not typically cause a reaction in most people. Because of this, the FDA does not require that it is labeled on products. You can speak with your allergist about your unique situation. Cold-pressed, expelled, or extruded soy oils should be avoided as they can contain small amounts of soy protein.
Reactions to Soy
Allergic reactions to soy are generally mild, but severe reactions have been reported. It is usually recommended for all kids with soy allergies to have an epi-pen with them at all times. Epinephrine is used to treat anaphylaxis, a severe reaction to allergies.
Krystyn Parks is a Registered Dietitian and Lactation Consultant who specializes in feeding children. She has a Master’s Degree in Nutritional Science from California State University Long Beach. She is an International Board Certified Lactation Consultant and has been registered with the Commission on Dietetic Registration since 2013.