Infant soy allergy occurs when a baby’s body mistakenly treats a harmless substance – soy – as a harmful one. (See our main allergies page for more information about preventing and identifying reactions to various foods, plus a list of potential allergens).
IMPORTANT: The information given here is meant as a guide and should not be taken as professional medical advice.
If you are concerned that your child may be allergic to any foods, consult a doctor immediately.
And always discuss the introduction of any new foods with a medical professional before giving them to your child.
Soybeans are part of the legume family, are very high in protein and contain all eight essential acids. The word “soy” comes from the Japanese word “shoyu”.
Soy is known by various names, including
Allergies to soy are fairly common, particularly among infants. The average age of diagnosis is 3 months – many babies that are allergic to soy are also allergic to cows’ milk. It is unclear which component of soy causes these reactions, but scientists have found soy to contain at least 15 allergenic proteins.
It is also believed that introducing foods containing soy before 6 months of age can increase the risk of infant soy allergy.
Many parents prefer to delay the introduction of soy until at least 8 months, or avoid it altogether for the first year.
NOTE: If your baby is allergic to soy, he may also react to green peas, chickpeas, green beans, lima beans, barley, wheat or rye. These foods should be introduced with care, under the supervision of your child’s doctor.
Soy contains many essential proteins, vitamins and minerals – so eliminating it from your baby’s diet means that you need to provide these essential elements from alternative sources.
Please note that this table is meant as a guide – if your baby is allergic to soy, it is important to discuss his nutritive needs with a dietician. These foods are not suitable for babies of all ages – please visit
for guidelines on which foods to introduce to your baby at each stage.
When you make your own baby food, you can be 100% sure of what it contains, which is very important if your child has an allergy to a particular food.
Soy, however, appears in many forms and in many foods. People allergic to it may react in different ways – and some foods, such as soybean oil (which does not contain protein) may not cause a reaction at all. Nevertheless, it is important to be aware of the foods that may contain it – and to ensure that anyone else who cares for your baby is aware of these foods too!
Always check the labelling on any commercially prepared foods, as they may contain some form of soy. Look for any of the following ingredients, which are associated with soy –
Most babies do grow out of their allergies to soy, usually by 2 years of age. At that point, an allergist will work with you to decide when to test your baby, to determine if he has outgrown the problem.