title: Sex differences in the endocrine system in response to protein intake early in life.
abstract: BACKGROUND
  Nutritional factors during a sensitive period can influence child development in a sex-related manner.
  
  
  OBJECTIVE
  Our aim was to investigate whether sex modulates the responses of relevant biochemical parameters and growth to different protein intakes early in life.
  
  
  METHODS
  In a randomized controlled trial, formula-fed infants were assigned to receive formula with higher protein (HP) or lower protein (LP) content. The main outcome measures were insulin-like growth factor (IGF)-1 axis parameters, weight, length, BMI, leptin, and C-peptide/creatinine ratio at 6 mo of age. Dietary intake during the first 6 mo of life was also assessed.
  
  
  RESULTS
  The IGF-1 axis response to HP feeding was modulated by sex. Total and free IGF-1 and IGF binding protein 3 concentrations were higher in girls than in boys. Compared with the LP diet, the HP diet was associated with higher IGF-1 and lower IGF binding protein 2 secretion. The response to this HP content formula tended to be stronger in girls than in boys. The HP diet was associated with a higher C-peptide/creatinine ratio. The leptin concentration was higher in girls than in boys and was correlated to the IGF-1 axis parameters. No interaction between sex and nutritional intervention was shown on growth.
  
  
  CONCLUSIONS
  Our findings show that the endocrine response to a high protein diet early in life may be modulated by sex. The IGF-1 axis of female infants shows a stronger response to the nutritional intervention than does that of male infants, but there is no enhanced effect on growth. This trial was registered at clinicaltrials.gov as NCT00338689.
authors.affiliation: From Universitat Rovira i Virgili, Tarragona, Spain.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Closa-Monasterolo
authors.forename: Natàlia
authors.initials: N
authors.lastname: Ferré
authors.forename: Verónica
authors.initials: V
authors.lastname: Luque
authors.forename: Marta
authors.initials: M
authors.lastname: Zaragoza-Jordana
authors.forename: Veit
authors.initials: V
authors.lastname: Grote
authors.forename: Martina
authors.initials: M
authors.lastname: Weber
authors.forename: Berthold
authors.initials: B
authors.lastname: Koletzko
authors.forename: Piotr
authors.initials: P
authors.lastname: Socha
authors.forename: Dariusz
authors.initials: D
authors.lastname: Gruszfeld
authors.forename: Roman
authors.initials: R
authors.lastname: Janas
authors.forename: Annick
authors.initials: A
authors.lastname: Xhonneux
authors.forename: Elena
authors.initials: E
authors.lastname: Dain
authors.forename: Silvia
authors.initials: S
authors.lastname: Scaglioni
authors.forename: Joaquin
authors.initials: J
authors.lastname: Escribano
mesh_terms: D001827:Body Height; D015992:Body Mass Index; D001835:Body Weight; D002657:Child Development; D003404:Creatinine / Q000032:analysis / Q000378:metabolism; D004044:Dietary Proteins / Q000008:administration & dosage*; D004311:Double-Blind Method; D004703:Endocrine System / Q000502:physiology*; D005260:Female; D006801:Humans; D007223:Infant; D041943:Infant Formula / Q000008:administration & dosage; D007227:Infant Nutritional Physiological Phenomena; D018971:Insulin-Like Growth Factor Binding Protein 2 / Q000032:analysis / Q000378:metabolism; D007334:Insulin-Like Growth Factor I / Q000032:analysis / Q000378:metabolism; D020738:Leptin / Q000032:analysis / Q000378:metabolism; D008297:Male; D009752:Nutritional Status; D012737:Sex Factors
chemical_list: D004044:Dietary Proteins; D018971:Insulin-Like Growth Factor Binding Protein 2; D020738:Leptin; D007334:Insulin-Like Growth Factor I; D003404:Creatinine