Effects of Prebiotic-Containing Infant Formula on Gastrointestinal Tolerance and Fecal Microbiota in a Randomized Controlled Trial

Background: Prebiotic-containing infant formula may beneficially affect gastrointestinal tolerance and commensal microbiota composition. Objective: Assess gastrointestinal tolerance and fecal microbiota, pH, and short-chain fatty acid (SCFA) concentrations of infants consuming formula with or without prebiotics. Design: Full-term formula-fed infants were studied to a breastfed comparison group (BF). Formula-fed infants (FF) were randomized to consume a partially hydrolyzed whey formula with (PRE) or without (CON) 4 g/L of galacto-oligosaccharides and fructo-oligosaccharides (9:1). Fecal bacteria, pH, and SCFA were assessed at baseline, 3 weeks, and 6 weeks. Caregivers of patients recorded stool characteristics and behavior for 2 days before the 3- and 6-week visits. Results: Feces from infants fed PRE had a higher absolute number (P = .0083) and proportion (P = .0219) of bifidobacteria than CON-fed infants and did not differ from BF. BF had a higher proportion of bifidobacteria than CON (P = .0219) and lower number of Clostridium difficile than FF (P = .0087). Feces from formula-fed infants had higher concentrations of acetate (P < .001), butyrate (P < .001), propionate (P < .001), and total SCFAs (P = .0230) than BF; however, fecal pH was lower (P = .0161) in PRE and BF than CON. Prebiotic supplementation did not alter stool patterns, tolerance, or growth. BF had more frequent stools that were yellow (P < .0001) and more often liquid than FF (P < .0001). Conclusions: Infant formula containing the studied oligosaccharides was well tolerated, increased abundance and proportion of bifidobacteria, and reduced fecal pH in healthy infants.