Soy allergy: common foods with soy, and where it hides in restaurant dishes
By the Menulta editorial team · Facts checked 15 October 2026 · Updated 15 October 2026
The short answer
A soy allergy is an immune reaction to proteins in soybeans. It is most common in babies and young children, and many outgrow it. People with a soy allergy must avoid soybeans and soy products such as soy sauce, tofu, tempeh, miso, edamame, soy milk and soy flour. In EU law, fully refined soybean oil is exempt from allergen labelling because refining removes almost all the protein. Unrefined soy oil and soy lecithin are not exempt.
Common foods with soy
Soy is the main ingredient in many Asian staples and a common additive in processed foods across Europe.
- Soy sauce, tamari and shoyu (most soy sauce also contains wheat)
- Tofu, tempeh, miso, natto and edamame
- Soy milk, soy yoghurt and soy-based desserts
- Textured vegetable protein (TVP) and many meat-free burgers, sausages and mince
- Soy flour in some breads, cakes and gluten-free products
- Soy lecithin (often E322) in chocolate, spreads and bakery products
- Hydrolysed vegetable protein and some stock cubes, gravies and seasonings
Soy oil and soy lecithin: the two confusing ones
Annex II of Regulation (EU) 1169/2011 exempts fully refined soybean oil and fat from allergen declaration, along with certain tocopherols and sterols derived from soy. Refining removes almost all of the protein that causes reactions. Cold-pressed or unrefined soy oil keeps more protein and is not exempt.
Soy lecithin is not exempt. It is a soy product and must be declared whenever it is used in a dish. It appears in amounts small enough that some soy-allergic people tolerate it, but that is a decision for the guest and their doctor, not the restaurant. Declare it and let the guest choose.
Where soy hides in restaurant dishes
| Dish or component | Possible soy source |
|---|---|
| Marinades and glazes | Soy sauce, miso, teriyaki |
| Asian-style dressings and dips | Soy sauce, soy-based mayonnaise |
| Vegetarian and vegan mains | Tofu, TVP, soy-based meat alternatives |
| Breads and burger buns | Soy flour or soy lecithin |
| Chocolate desserts | Soy lecithin in the chocolate |
| Stocks, gravies, sauces | Hydrolysed vegetable protein, stock cubes |
| Fried food | Oil that is not fully refined, or shared with tofu |
| Coffee bar | Soy milk as a dairy alternative, cross-contact on steam wands |
Soy, milk and the dairy-free trap
Soy is the classic substitute for milk, which creates a trap. A guest who asks for a dairy-free dish may be offered soy milk or a soy-based dessert. If that guest is also allergic to soy, which is not unusual in children with milk allergy, the substitution causes the reaction. When swapping one allergen out, check the substitute against the guest's full list.
The same applies at the coffee bar. Soy milk steamed with the same wand as cow's milk moves both allergens between drinks. Clean the wand between drinks for allergic guests, or use a separate jug.
Serving a guest with a soy allergy
Check the written allergen record for every component, read the labels of bought-in sauces, breads and chocolate, and confirm which frying oil you use. Avoid soy sauce substitutes unless their labels are checked: many 'coconut aminos' or 'liquid aminos' products are soy-free, but some aminos are made from soy. If a dish depends on soy for its flavour, it is usually safer to recommend a different dish than to improvise a soy-free version during service.
Questions to ask your suppliers about soy
Because soy turns up in so many processed products, the supplier conversation matters more than for most allergens. Ask whether the frying oil is fully refined soybean oil, a blend, or another oil. Ask whether breads and burger buns contain soy flour or soy lecithin. Ask for current specifications for stock bases, gravies and seasoning blends, which often contain hydrolysed soy protein. Ask whether meat-free products contain soy, and whether they are made on lines that also handle it.
Keep the answers in writing, filed with your allergen record, and repeat the questions whenever a product is substituted or a supplier reformulates. A change of bun supplier is one of the commonest ways soy appears on a plate where it was never declared.
Sources
This guide is general information, not medical or legal advice. Guests with an allergy should follow their doctor's advice. Operators should confirm their own setup with their food safety adviser or local authority.