Is soy formula recommended in children who have a cow's milk protein allergy?

• A. Yes
• B. No, since a high percentage of children who are allergic to cow's milk protein will also be allergic to soy protein; the AAP recommends a trial use of either hydrolyzed or free amino acid-containing formula
• C. Only for infants under 6 months
• D. It depends on age

Answer: (B)

The main idea is that cow's milk protein allergy is managed with formulas that minimize allergenicity, and soy protein is not reliable for infants with CMPA. A sizable number of children with CMPA also react to soy protein, so relying on soy formula can continue allergy symptoms rather than resolve them. That’s why the recommended approach is to use extensively hydrolyzed formula (proteins broken down into smaller pieces) or amino acid–based formula (proteins fully broken down to amino acids). These options reduce the likelihood of an allergic reaction and are the standard first-line choices for CMPA. Some children may outgrow CMPA and later tolerate soy, but reintroduction should be guided by a clinician, not used as the initial or routine management.