Postnatal High Protein Intake Can Contribute to Accelerated Weight Gain of Infants and Increased Obesity Risk

Worldwide, 38% of women are now overweight (BMI 25-30) or obese (BMI ≥30). There is increasing evidence that maternal obesity can result in unfavorable (epigenetic) pre- and postnatal programming of important genes of the offspring. Infants of overweight mothers show faster weight gain during infancy, which is associated with higher risk of obesity during childhood and adult life. This can have lifelong consequences such as increased risk of noncommunicable diseases. Many studies indicate that infants of obese and nonobese mothers who were fed traditional (high-protein) formulas gain more rapidly weight than breastfed infants. An updated meta-analysis (n = 1,150) indicates that infants from four continents who were fed a whey-based, low-protein (1.8 g/100 kcal) formula with an essential amino-acid profile closer to breast milk grow in accordance with the World Health Organization (WHO) growth standard (0-4 months). A new experimental low-protein (1.61-1.65 g protein/100 kcal) formula for infants between 3 and 12 months of age was recently tested in two randomized clinical trials. One trial in the general US population indicates lower weight between 4 and 12 months of age in infants fed the low-protein formula when compared to infants on the high-protein formula (p = 0.031). Weight gain was not inferior to the WHO growth standards. Longitudinal analysis of odds ratios from 4 to 12 months of age showed a lower incidence of infants with weight >85th percentile in the low-protein group compared with the high-protein group (p = 0.015). In the second trial, which was conducted in Chile and included infants of mothers with BMI >25, infants fed the low-protein formula gained less weight between 4 and 12 months (p = 0.022) and until 24 months (p = 0.031) than the high-protein group. Weight gain was similar to the breastfed reference group. In both trials, biomarkers of protein metabolism (insulin-like growth factor-1 and C-peptide) of the low-protein groups were closer to breastfed infants than the respective biomarkers of the high-protein groups. Health economic analyses indicate that feeding low-protein formulas to nonbreastfed infants would result in cost savings for both the individual and the society. Preventive measures against childhood and adult obesity should include promotion of breastfeeding for 6 months or longer, and use of low-protein formulas in nonbreastfed infants.