A metabolic balance study in term infants fed lactose-containing or lactose-free formula.

Lactose-free (L-) formulas are recommended for infants with conditions affecting lactose digestion. Cows' milk protein-based formulas containing other carbohydrate sources are most often used for such infants. This study compared fat absorption and absorption and retention of nitrogen, calcium, phosphorus, and magnesium in term infants fed either a L- or standard lactose-containing (L+) bovine milk protein-based formula. Data from three single-centre, double-blind, randomized, parallel-group metabolic balance studies were combined. After a 4-7-d equilibration period on either L- or L+ formula, a 72-h balance study was performed. Twenty infants received L- and 21 received L+ formula. Besides the L- group having a higher percentage of males (65%) and the L+ group a higher percentage of females (52.4%), other baseline measurements were similar. The majority of nutrient balance data was similar between the two groups. Exceptions were relative nitrogen absorption, calcium intake and calcium retention, magnesium retention, and faecal phosphorus excretion, all of which were significantly higher in the L- group. Vitamin D supplementation did not significantly affect either calcium or phosphorus data. This new L- formula provided similar nutrients and is a suitable alternative to a L+ formula in term infants requiring L- feedings.