Consumir mucha proteína mejora el crecimiento durante los seis primeros meses de vida

Título original : Milk protein intake, the metabolic-endocrine response, and growth in infancy: data from a randomized clinical trial

Autores : Socha, P (Socha, Piotr)1; Grote, V (Grote, Veit)2,3; Gruszfeld, D (Gruszfeld, Dariusz)1; Janas, R (Janas, Roman)1; Demmelmair, H (Demmelmair, Hans)2; Closa-Monasterolo, R (Closa-Monasterolo, Ricardo)4; Subias, JE (Escribano Subias, Joaquin)4; Scaglioni, S (Scaglioni, Silvia)5; Verduci, E (Verduci, Elvira)5; Dain, E (Dain, Elena)6; Langhendries, JP (Langhendries, Jean-Paul)7; Perrin, E (Perrin, Emmanuel)8; Koletzko, B (Koletzko, Berthold)2

Resumen :
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. Am J Clin Nutr 2011;94(suppl):1776S-84S.

Direcciones :
1. Childrens Mem Hlth Inst, Warsaw, Poland
2. Univ Munich, Med Ctr, Dr von Hauner Childrens Hosp, Munich, Germany
3. Univ Munich, Inst Social Pediat & Adolescent Med, Munich, Germany
4. Univ Rovira & Virgili, IISPV, Tarragona, Spain
5. Univ Milan, Dept Pediat, Milan, Italy
6. Univ Libre Bruxelles, Dept Pediat, Brussels, Belgium
7. CHC St Vincent, Liege, Belgium
8. Danone Res Ctr Specialized Nutr, Schiphol, Netherlands