We thank you for the thoughtful comments. We agree that the long-term consequences of partially hydrolyzed cow's milk formula are not fully known and that the use of PHF for the general population remains controversial. However, the whey-based hydrolysate, which was shown to reduce allergy in high-risk infants, has been approved and used as a routine infant formula in North America for 20 years.
We do not know every potential characteristic or component in formulas (intact protein formulas included) that could be detrimental. It is also clear that not all hydrolysates are compositionally or functionally the same. The formula leading to adverse effects in animals discussed by Professor Marini1 is a hydrolyzed formula with a median molecular weight of 5000 and made with a combination of casein and whey. This formula is significantly different than either the casein-based extensive hydrolysate or whey-based hydrolysate, which have been studied for primary prevention.2 Casein/whey hydrolysates have not been shown to be effective in allergy risk reduction.3 Recommendations for allergy prevention should only be made for formulas that have demonstrated efficacy in clinical trials and have a good safety record.
Hays T, Wood R. Use of a Partially Hydrolyzed Formula in the Dietary Prevention of Allergic Disease—Reply. Arch Pediatr Adolesc Med. 2006;160(8):854-855. doi:10.1001/archpedi.160.8.855-a