Soy Milk

Soy milk can be introduced as an ingredient in solid food (but not as a drink) as soon as baby is ready to start solids. Hold off on soy milk as a drink until after baby’s first birthday so as not to displace breast milk and formula intake in the first year of life. 

Soy milk has been consumed for over a thousand years, originating in East Asia where it became an integral part of many traditional diets. Its history dates back to the Han dynasty in China, where it was first made by soaking, grinding, and boiling soybeans. Outside of Asia, soy milk gained prominence in the late 20th century as part of the growing interest in plant-based diets.

• Choose soy milk fortified with calcium and vitamin D, when available. 

No. Soy milk presents a low risk when safely prepared for a child’s age and developmental ability, though, in theory, an individual could choke on any food. To reduce the risk, prepare and serve soy milk in an age-appropriate way as described in the How to Serve section. As always, create a safe eating environment and stay within reach of baby during meals. 

Learn the signs of choking and more about choking first aid in our free guides, Infant Rescue and Toddler Rescue.

Yes. Soy milk is made with soybean, which is a common food allergen among infants, and may contain other common allergens. Read the label on soy milk carefully before serving.

However, there is good news: less than 1% of children are allergic to soy, reactions tend to be mild (although severe reactions to soy have been reported), and almost 70% of children outgrow their allergy by age 10.^[1][2] For these reasons, soy is not classified as a Global Priority Allergen by the World Health Organization.^[3] 

Although a significant percentage of children with soy allergy may also be sensitized to peanut (and vice versa) on testing, this does not always translate into a clinical allergy.^[2][4] If baby has experienced an allergic reaction to soy, and you have not yet introduced peanut, you may wish to introduce peanut after consultation with your doctor. However, there is no need to remove peanut from the diet or pursue peanut allergy testing if it is already being eaten without any reaction. Likewise, babies with peanut allergy do not need to eliminate soy if it is already well-tolerated in the diet.

Some babies with cow’s milk allergy are sensitive to soy. In fact, 10 to 14% of young children with cow’s milk allergy also present with allergic reactions to soy, and 30-50% of US infants with non IgE-mediated cow’s milk allergy may co-react to soy.^[5][6][7][8] This is more likely to be seen in babies under 6 months of age.^[6] For this reason, many pediatricians recommend that babies with a known milk allergy preemptively avoid both cow’s milk and soy for the first 6 months of life, and they may recommend extensively hydrolyzed or elemental infant formula instead of soy formula during this time.

Individuals with Oral Allergy Syndrome (also known as food-pollen allergy syndrome), especially those allergic to birch pollen, may experience symptoms after the ingestion of soy. Oral Allergy Syndrome typically presents with short-lived itching, tingling, or burning in the mouth, and is unlikely to result in a severe reaction. That said, serious reactions to soy in individuals with birch pollen allergy have been reported, most commonly in individuals who are also allergic to peanut.^[9][10]

Soy is a known cause of food protein-induced enterocolitis syndrome, also known as FPIES. FPIES is a delayed allergy to food protein which causes the sudden onset of repetitive vomiting and diarrhea to begin a few hours after ingestion. This is termed acute FPIES. Left untreated, the reaction can result in significant dehydration. When soy is in the diet regularly, FPIES can present as reflux, weight loss, and failure to thrive. This is termed chronic FPIES. Symptoms generally improve with elimination of soy from the baby’s diet. Thankfully, like other forms of soy allergy, FPIES that presents early in life is generally outgrown by the time the child has reached 3 to 5 years of age—often earlier.^[11]

When introducing soy to baby, start with a simple food that isolates the ingredient, such as soy yogurt, plain tofu strips, or soy milk mixed into mashed vegetables, and watch for any adverse reactions. As with all common allergens, start by serving a small quantity for the first few servings, and if there is no adverse reaction, gradually increase the quantity over future meals. Once common food allergens are successfully introduced, it is recommended to keep them in the diet regularly (twice weekly, if possible).

Yes, although it does not provide the same complete nutrition that breast milk and formula offer to growing babies, so only use soy milk as an ingredient in solid food under 12 months of age. Hold off on soy milk as a drink until after baby’s first birthday so as not to displace breast milk and formula intake in baby’s first year of life.

Soy milk provides plant-based protein, iron, and some healthy fat. Fortified varieties also tend to contain calcium, vitamin D, and B12, which are important for growth and bone development.