Lactose-free milk protein-based infant formula: impact on growth and gastrointestinal tolerance in infants.

Lactose, the major carbohydrate in human milk and standard milk-based formulas, provides energy for growth in infants. The use of lactose-free milk protein-based infant formulas has increased in the United States. However, clinical studies of their impact on growth, safety, and gastrointestinal tolerance in infants are limited. Thus, a prospective, blinded, randomized clinical trial was conducted in healthy, normal-term infants fed an experimental lactose-free milk protein-based formula (NoLAC; n = 63) versus a standard commercial lactose-containing milk-based formula (LAC; n = 65) for 112 days. Growth (weight, length, and head circumference) was similar and normal in both groups (weight gain: NoLAC = 31.1 ± 0.9 g/day, LAC = 29.4 ± 0.9 g/day, mean ± SEM; P = .895). Serum biochemistries for both groups were within infants' normal reference ranges. Both groups had comparable tolerance but the NoLAC group had softer stools and lower spit-ups. Thus, the study suggests that absence of lactose in milk-based formula does not adversely affect normal growth in term infants.