Soy Milk Allergy

Soy allergies can make life tough for you and your child. Soy allergy is most commonly found in infants, who typically begin showing symptoms around three months of age. The good news is that most children outgrow soy allergy during childhood.1

Soy allergy symptoms can include (but are not limited to!) asthma, atopic dermatitis, colitis, diarrhea, eczema, fever, itching, vomiting and wheezing. Symptoms typically start appearing within 48 hours after a child eats or drinks soy protein. Unfortunately, up to 50% of children with cow milk allergy may also be allergic to soy protein.6

If you suspect your child is allergic to soy, completely remove soy products from his or her diet and call her doctor or dietitian. Under their guidance, they may ask you to cautiously return soy to your child’s diet to see if symptoms return, or the allergist may want to do a supervised trial in the office to confirm an allergy.

If your child is allergic to soy, you might want to keep an eye out to see how he or she responds to other legumes such as peas, peanuts, lentils and garbanzo beans. It’s possible your child may also be allergic to these. 

How Neocate Can Help

Neocate can play a key role in the dietary management of children with soy allergy. Neocate is based on free amino acids, the building blocks of all protein, and it contains no soy protein. Because amino acids are the simplest source of protein, Neocate is easier for infants and children to digest and absorb. Neocate has neither whole nor fragmented protein chains that can trigger an allergic response. Amino acid formulas, such as Neocate, are the most hypoallergenic formulas available.

Neocate has been clinically shown to help with gastrointestinal conditions in as little as three days2 and to improve other allergy-related conditions such as skin rash, eczema or GER in up to 14 days.3,4 Neocate provides an adequate source of nutrition and has been seen to promote normal and catch-up growth in infants.5,6 The following table compares some of the different infant formulas and identifies the protein source.

Protein Source Protein Type
Allergic Reaction
Cow Milk Protein

Goat Milk Protein

Whole Protein

+ + + +
Soy Protein Whole Soy Protein and Soy Isolate + + +
Extensively Hydrolyzed Protein Fragments of Cow Milk Protein
Fragments of Soy Protein
Amino Acids
• Protein in its simplest, completely broken down form

++++ Very likely 
+++ Likely
+ Somewhat likely for children with severe cow and soy milk allergy
- Not likely

More information on food allergies can be found in our Neocate parent guide.


1. Boyce et al. Guidelines for the diagnosis and management of food allergy in the United States: report of the NIAID-sponsored expert panel. J Allergy Clin Immunol 2010; 126(6 Suppl):S1-58.
2. de Boissieu D et al. Allergy to extensively hydrolyzed cow’s milk proteins in infants: Identification and treatment with an amino acid-based formula. J. Pediatr 1997; 131:744-747.
3. Vanderhoof JA et al. Intolerance to protein hydrolysate infant formulas: An underrecognized cause of gastrointestinal symptoms in infants. J. Pediatr 1997; 131:741-744.
4. Hill DJ et al. The natural history of intolerance to soy and extensively hydrolyzed formula in infants with multiple food protein intolerance. J. Pediatr 1999; 135:118-121.
5. Isolauri E et al. Efficacy and safety of hydrolyzed cow’s milk and amino acid-derived formulas in infants with cow’s milk allergy. J. Pediatr 1995; 127:550-557.
6. Niggemann B et al. Prospective, controlled, multi-center study on the effect of an amino acid-based formula in infants with cow’s milk allergy/intolerance and atopic dermatitis. Pediatr Allergy Immunol 2001; 12:78-82.
7. Bishop JM et al. Natural history of cow milk allergy: clinical outcome. J Pediatr 1990 Jun; 116(6):862-7.