Softer More Frequent Stools in Infants With Difficult Stooling Fed Hydrolyzed Protein Formula With Added Prebiotics: Randomized Controlled Trial

OBJECTIVE: To evaluate stool consistency in infants with reported hard or infrequent stools fed hydrolyzed protein formula with added prebiotics designed to promote stool softening. METHODS: In this multi-center, double-blind, controlled study, eligible infants (28–300 days of age at enrollment) were randomized to: partially hydrolyzed cow’s milk protein formula (PHF, 75% carbohydrate as lactose; 12 mg Mg/100 kcal; n = 49) or routine intact protein cow’s milk-based infant formula (Control, 92% carbohydrate as lactose; 8 mg Mg/100 kcal; n = 51) over a 14-day period. Both formulas had a prebiotic blend (polydextrose and galactooligosaccharides, 4 g/L; 1:1 ratio). Parent-reported stool consistency (hard = 1 through watery = 5) and other daily outcomes were collected by diary. Endpoint stool consistency (mean score over last 3 days of study feeding) was the primary outcome. Adverse events were recorded. RESULTS: Baseline stool consistency (Control: 1.4 ± 0.1, PHF: 1.4 ± 0.1) and frequency were similar between groups; the majority had hard (n = 61, 64%) or formed (n = 30, 32%) stools. Stool consistency became softer over Day 1–3 (Control: 2.5 ± 0.1, PHF: 2.6 ± 0.1) and remained similar from Day 4 to 6 through study end (post hoc analysis). For PHF vs Control, endpoint stool consistency was significantly softer (3.4 ± 0.1 vs 3.0 ± 0.1; P = 0.019) and frequency significantly higher (1.5 ± 0.1 vs 1.0 ± 0.1; P = 0.002). Crying, fussing, and appearance of pain during stooling decreased from baseline to study end in both groups. Formula intake, infant fussiness and incidence of adverse events were similar between groups. CONCLUSION: An infant formula designed to promote stool softening was well-tolerated and associated with softer, more frequent stools in infants with reported hard or infrequent stools.