Foods that contain soy don’t always have the word “soy” on the product label. This can make shopping or dining out difficult if you have a soy allergy or want to eliminate soy from your diet for other reasons. Vegetarians and vegans may be especially challenged.
This article describes some of the hidden sources of soy and how to recognize them on product labels. It also lists common and uncommon sources of soy (including non-food sources) and the best alternatives if you are soy-free.
What to Know About Product Labeling
The Food Allergen Labeling & Consumer Protection Act (FALCPA) requires manufacturers to list soy ingredients on product labels in plain, easy-to-understand language.
However, the FALCPA does not require a manufacturer whose product contains refined soy oil and/or soy lecithin as a releasing agent to include “contains soy” on their label. This is due to the fact that studies have yet to show that there is enough soy protein in these ingredients to cause an allergic reaction in most people.
This doesn’t mean that someone with an extreme sensitivity to soy might not still react to soy even in these trace amounts.
Also, the guidelines do not apply to “raw agricultural commodities” such as fruits, vegetables, eggs, milk, meat, or other foods in their natural state. All of these are possible sources of soy, including soy-based waxes or horticultural oils used on fruits and processed chickens.
Some manufacturers may include statements on a food label indicating a potential for soy cross-contamination. These include statements like “may contain soy,” “produced on shared equipment with soy,” or “produced in a facility that also processes soy.”
Even so, these warnings are voluntary and not required under FALCP regulations.
Common Food Sources of Soy
Soy is a common ingredient in many Asian cuisines but may be difficult to recognize on a menu. It is important to know that the following items contain soy and should be avoided if you have a soy allergy:
Bean sproutsEdamame beansKinakoMisoNatto NimameOkaraShoyu Soy sauceSoyaSoybean curds Soybean granulesTamariTempehTeriyaki sauceTofuYuba
Soy-Based Ingredients
It is not always easy to recognize the presence of soy on a label, as other words are used in their place. These processed ingredients are soy-based:
Hydrolyzed soy protein (HSP) Mono- and diglycerides Monosodium glutamate (MSG) Textured vegetable protein (TVP)
There are other ingredients that may or may not contain soy. It is important to contact the manufacturer of the product to find out the source of the ingredient.
These include:
Bulking agents Hydrolyzed plant protein (HPP) Hydrolyzed vegetable protein (HVP) Gum arabic Guar gum Lecithin Mixed tocopherols “Natural flavoring” Stabilizer Thickener Vegetable gum, starch, shortening, or oil Vitamin E
Foods That May Contain Soy
You might be surprised to learn that a number of common foods often contain some form of soy. It is important to be extra cautious about eating these if you are unable to get a complete ingredient list:
Asian foodsBaked goods and baking mixesBouillon cubesCandyCerealChicken brothChicken (raw or cooked) processed with chicken brothChocolateDeli meats made with hydrolyzed soy proteinEnergy bars or nutrition barsHamburger meat with soy protein fillersHamburger buns made with added soy flourImitation dairy foodsInfant formulaMargarineMayonnaiseNutrition supplementPeanut butter and peanut butter substitutesProtein powders made with soy protein powderSauces, gravies, and soupsSausages and hot dogs made with soy protein fillersSmoothiesVegetable brothVegetarian meat substitutes
Allergy Cross-Reactivity
Some people with peanut allergies may also be allergic to soy protein. People with soy allergies may cross-react with peanuts or other legumes, such as beans or peas.
While a soy allergy tends to be less severe than other food allergens, cross-reactivity to peanuts can increase the severity. Some studies have reported fatal reactions in people with severe peanut allergies.
With that said, most people with soy allergy can safely tolerate other legumes because the legume family has over 30 species.
Even so, don’t assume that you are allergic to the broad category of beans and legumes just because you have a soy or peanut allergy. The restriction of these foods could lead to a nutritional deficiency.
Soy Allergy in Infants
Soy protein may cause a digestive disorder in childhood called food-protein-induced enterocolitis syndrome (FPIES). Infants can get a similar set of symptoms from cow’s milk protein, known as cow’s milk protein-induced enterocolitis.
Between 10% and 14% of babies who are allergic to cow’s milk will develop a reaction when given a soy-based infant formula, according to a 2018 study published by the World Allergy Organization Journal.
Protein Alternatives for a Soy-Free Diet
If you have a soy allergy, you must avoid tofu and tempeh, which are found in most textured vegetable protein meat substitutes and many vegetarian convenience foods.
Instead, you can choose from these eight high-protein foods (all of which are vegetarian-diet friendly):
Milk and eggs: Lacto-ovo-vegetarians use these as a rich source of protein and vitamin B-12. The caveat is that milk and eggs are also common allergens, and some people may be sensitive to them as well as soy. Beans: One cup of cooked black beans provides 15 grams of protein. You can enjoy many varieties of this inexpensive source of protein, iron, folate, and magnesium. Nuts: Nuts are common allergens and so they can’t be enjoyed by everyone. However, they are rich in protein and nutrients such as vitamin E and phosphorus. Seitan: This is a plant-based meat substitute made from wheat flour gluten. You just need to check that it isn’t made with any added soy. Whole wheat: Look for whole grain products rather than refined whole wheat. These are a great source of fiber, selenium, and manganese. Quinoa: This ancient Incan grain is nutritionally complete. One cup of quinoa has 23 grams of protein and it is high in fiber, magnesium, and phosphorus. Flaxseed: Ground flaxseed is an easy way to add protein and fiber to a smoothie, and you can bake it into baked goods. Oat bran: The bran is removed from processed instant oats, but you can add it back in for a protein boost or as a rich source of dietary fiber for baked goods.
