Milk protein intake, the metabolic-endocrine response, and growth in infancy: data from a randomized clinical trial
Piotr Socha, Veit Grote, Dariusz Gruszfeld, Roman Janas, Hans Demmelmair, Ricardo Closa-Monasterolo, Joaquín Escribano Subías, Silvia Scaglioni, Elvira Verduci, Elena Dain, Jean-Paul Langhendries, Emmanuel Perrin, Berthold Koletzko, European Childhood Obesity Trial Study Group, Annick Xhonneux, Anna Stolarczyk, Jerzy Socha, Roman Janas, Ewa Pietraszek, Sabine Verwied-Jorky, Sonia Schiess, Ingrid Pawellek, Uschi Handel, Iris Hannibal, Michaela Fritsch, Helfried Groebe, Anna Reith, Renate Hofmann, Pascale Poncelet, Verónica Luque Moreno, Georgina Méndez Riera, Marta Zaragoza-Jordana, Natalia Ferrè, Carlo Agostoni, Fiammetta Vecchi, Piotr Socha, Veit Grote, Dariusz Gruszfeld, Roman Janas, Hans Demmelmair, Ricardo Closa-Monasterolo, Joaquín Escribano Subías, Silvia Scaglioni, Elvira Verduci, Elena Dain, Jean-Paul Langhendries, Emmanuel Perrin, Berthold Koletzko, European Childhood Obesity Trial Study Group, Annick Xhonneux, Anna Stolarczyk, Jerzy Socha, Roman Janas, Ewa Pietraszek, Sabine Verwied-Jorky, Sonia Schiess, Ingrid Pawellek, Uschi Handel, Iris Hannibal, Michaela Fritsch, Helfried Groebe, Anna Reith, Renate Hofmann, Pascale Poncelet, Verónica Luque Moreno, Georgina Méndez Riera, Marta Zaragoza-Jordana, Natalia Ferrè, Carlo Agostoni, Fiammetta Vecchi
Abstract
Background: Protein intake in early infancy has been suggested to be an important risk factor for later obesity, but information on potential mechanisms is very limited.
Objective: This study examined the influence of protein intake in infancy on serum amino acids, insulin, and the insulin-like growth factor I (IGF-I) axis and its possible relation to growth in the first 2 y of life.
Design: In a multicenter European study, 1138 healthy, formula-fed infants were randomly assigned to receive cow-milk-based infant and follow-on formulas with lower protein (LP; 1.77 and 2.2 g protein/100 kcal) or higher protein (HP; 2.9 and 4.4 g protein/100 kcal) contents for the first year. Biochemical variables were measured at age 6 mo in 339 infants receiving LP formula and 333 infants receiving HP formula and in 237 breastfed infants.
Results: Essential amino acids, especially branched-chain amino acids, IGF-I, and urinary C-peptide:creatinine ratio, were significantly (P < 0.001) higher in the HP group than in the LP group, whereas IGF-binding protein (IGF-BP) 2 was lower and IGF-BP3 did not differ significantly. The median IGF-I total serum concentration was 48.4 ng/mL (25th, 75th percentile: 27.2, 81.8 ng/mL) in the HP group and 34.7 ng/mL (17.7, 57.5 ng/mL) in the LP group; the urine C-peptide:creatinine ratios were 140.6 ng/mg (80.0, 203.8 ng/mg) and 107.3 ng/mg (65.2, 194.7 ng/mg), respectively. Most essential amino acids, IGF-I, C-peptide, and urea increased significantly in both the LP and HP groups compared with the breastfed group. Total IGF-I was significantly associated with growth until 6 mo but not thereafter.
Conclusions: HP intake stimulates the IGF-I axis and insulin release in infancy. IGF-I enhances growth during the first 6 mo of life. This trial was registered at clinicaltrials.gov as NCT00338689.
Source: PubMed