title: δ(15)N and δ(13)C in hair from newborn infants and their mothers: a cohort study.
abstract: BACKGROUND
  Protein intake in fetal life or infancy may play a key role in determining early growth rate, a determinant of later health and disease. Previous work has indicated that hair isotopic composition is influenced by diet and protein intake.
  
  
  METHODS
  This study analyzes the isotopic composition of hair obtained from 239 mother/newborn pairs randomly selected within a larger cohort enrolled in a study of pre- and postnatal determinants of the child's development and health. The isotopic compositions in nitrogen (δ(15)N) and in carbon (δ(13)C) were determined by isotope ratio mass spectrometry.
  
  
  RESULTS
  Mother and newborn hair δ(15)N were tightly correlated (Pearson r = 0.88). The mean δ(15)N and δ(13)C values of hair from newborn infants were significantly higher than those for the mothers: 9.7 ± 0.7 vs. 8.8 ± 0.6‰ (P < 0.0001) for δ(15)N and -20.0 ± 0.4 vs. -20.4 ± 0.4‰ (P < 0.0001) for δ(13)C. Maternal hair δ(15)N at parturition was slightly and positively correlated with estimates of protein intake (r = 0.14, P = 0.04).
  
  
  CONCLUSIONS
  Hair δ(15)N of the fetus is both highly dependent on and systematically higher than that of the mother. Whether quantitative and qualitative protein intake, disease, or hormonal status alter hair δ(15)N at birth remains to be determined.
authors.affiliation: Pédiatrie Multidisciplinaire-Nutrition de l'Enfant, Centre Hospitalier Universitaire de Poitiers, Poitiers, France.
authors.forename: Arnaud
authors.initials: A
authors.lastname: de Luca
authors.forename: Nathalie
authors.initials: N
authors.lastname: Boisseau
authors.forename: Illa
authors.initials: I
authors.lastname: Tea
authors.forename: Isabelle
authors.initials: I
authors.lastname: Louvet
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Robins
authors.forename: Anne
authors.initials: A
authors.lastname: Forhan
authors.forename: Marie-Aline
authors.initials: MA
authors.lastname: Charles
authors.forename: Régis
authors.initials: R
authors.lastname: Hankard
mesh_terms: D000328:Adult; D002247:Carbon Isotopes / Q000032:analysis*; D015331:Cohort Studies; D005260:Female; D006197:Hair / Q000737:chemistry*; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D013058:Mass Spectrometry; D009587:Nitrogen Isotopes / Q000032:analysis*
chemical_list: D002247:Carbon Isotopes; D009587:Nitrogen Isotopes