Efficacy of Soy-Based Formulas in Alleviating Gastrointestinal Symptoms in Infants With Milk-Based Formula Intolerance: A Randomized Clinical Trial

A randomized, blinded pilot clinical study was conducted to assess gastrointestinal (GI) tolerance in healthy, full-term infants (2-9 weeks old), whose pediatricians recommended a formula change due to perceived cow's milk formula intolerance. Infants were randomized and exclusively fed either a commercial control soy formula (SF; n = 22), an experimental partially hydrolyzed SF (10% hydrolyzed, n = 23), or a 5% hydrolyzed SF (n = 26) for 2 weeks. Age-matched reference cohorts (n = 72) with no GI intolerance on milk-based formula were assessed in parallel. Results indicated that all SF-fed groups contributed to reduction (P < .05) in common GI tolerance symptoms to levels not different from the non-symptomatic reference cohort at study end. The control SF group had more reduced fussiness, gas, and crying and higher formed stools versus hydrolyzed SF groups. In conclusion, the study suggests that SFs reduced GI intolerance symptoms in otherwise healthy infants with poor tolerance on milk-based formulas.