Low-protein formula slows weight gain in infants of overweight mothers.

Infant formulas provide more protein than breast milk. High protein intakes, as well as maternal obesity, are risk factors for later obesity. The present study tested whether a formula with lower protein content slows weight gain of infants of overweight mothers (body mass index [BMI] >25 kg/m). In a randomized double-blind study infants of overweight mothers received from 3 months an experimental (EXPL) formula with 1.65 g of protein/100 kcal (62.8 kcal/100 mL) and containing probiotics, or a control (CTRL) formula with 2.7 g of protein/100 kcal (65.6 kcal/100 mL). Breast-fed infants were studied concurrently. Primary assessment was between 3 and 6 months, although formulas were fed until 12 months. Biomarkers of protein metabolism (blood urea nitrogen, insulin growth factor-1, insulinogenic amino acids) were measured. Infants fed the low-protein EXPL formula gained less weight between 3 and 6 months (-1.77 g/day, P=0.024) than infants fed the CTRL formula. In the subgroup of infants of mothers with BMI>30 kg/m the difference was -4.21 g/day (P=0.017). Weight (P=0.011) and BMI (P=0.027) of EXPL infants remained lower than that of CTRL infants until 2 years but were similar to that of breast-fed infants. Blood urea nitrogen, insulin growth factor-1, and insulinogenic amino acids at 6 months were significantly lower in EXPL compared with CTRL. A low-protein formula with probiotics slowed weight gain between 3 and 6 months in infants of overweight mothers. Weight gain and biomarkers were more like those of breast-fed infants.