Metabolic Programming: Effects of Early Nutrition on Growth, Metabolism and Body Composition.

High protein requirements of premature infants during the first weeks of postnatal life are a well-established fact. Those infants gain fat-free mass and protein rapidly during the first weeks of postnatal growth and require a much higher protein/energy ratio than term infants. Recommended protein intakes are 3.5-4.0 g/kg per day. For term infants, on the other hand, FAO and WHO have recently lowered recommended protein intakes to better reflect our current knowledge about the protein concentration in breast milk during the first 12 months of lactation. Longitudinal randomized clinical trials now confirm that term infants who are fed infant and follow-up formulas with protein concentrations >2.25 g/100 kcal (high protein formulas) during the first year of life grow faster than indicated by the WHO growth standards. Rapid weight gain during infancy is a predictor of childhood and adult obesity. Infants fed high protein quality formulas with protein concentrations of 1.6-2.2 g/100 kcal from 3 to 4 months onwards experience weight gain that is very close to that of breastfed infants. Biomarkers (insulin or IGF-1) of infants receiving low protein formulas differ from those of infants receiving high protein formulas. Six-year-old children who received low protein formulas in the first year of life had a lower risk of childhood obesity (BMI >95th percentile of WHO standards) compared with children who received high protein formulas as infants. BMI at 5 years of age is similar in children who were breastfed or received low protein formulas as infants. It is most important that the new low protein formulas are safe and adequate for all healthy term infants. Based on new protein technologies, the levels of essential and branched-chain amino acids in low protein formulas are now close to those in breast milk. Safety has been confirmed by following anthropometric parameters to 5-6 years of age and comparing these parameters with the WHO growth standards. Body composition measurements indicate similar protein accretion between 3 and 6 months of age in infants fed high or low protein formulas. Longitudinal data on body composition indicate that children who received a low protein formula until age 12 months gain less fat between 6 and 60 months than children who received a high protein formula. Breastfeeding and the use of low/high protein quality formulas in term infants who cannot be breastfed can help support appropriate metabolic programming during this critical period and reduce the risk of later obesity.