The EFFECT Study: Probiotic and HMO Supplementation in Infants

This study is a single-center, prospective, randomized, open-label study of an infant probiotic (B. infantis EVC001) and a prebiotic supplement (LNT) in exclusively formula-fed infants. Nine subjects will be enrolled into three treatment arms: * Group 1: 8 x 10\^9 CFU B. infantis + LNT (3 g/L then 8 g/L) * Group 2: 8 x 10\^9 CFU B. infantis + LNT (6 g/L then 12 g/L) * Group 3: 8 x 10\^9 CFU B. infantis alone Study staff will be unblinded to the treatment assignments. Infants in all groups will receive a once-daily oral feeding of B. infantis EVC001 (8.0 x 10\^9 CFU) mixed with infant formula for 28 consecutive days. Two of the treatment groups (Group 1 \& Group 2) will also receive two dose-escalated concentrations of the prebiotic supplement (LNT) mixed with their daily infant formula: Group 1 will receive a concentration of 3 g/L for 2 weeks followed by 8 g/L for the next 2 weeks. Group 2 will receive a concentration of 6 g/L for 2 weeks followed by 12 g/L for the next 2 weeks. Infants consuming the LNT will cross over to the higher dose without a washout period in between. All infants will be evaluated for an additional 2 weeks after cessation of the supplement(s). The total duration of the study will be approximately 7 weeks.