title: Infant diet, gender and the normative development of vagal tone and heart period during the first two years of life.
abstract: Relationships between early postnatal diet and the development of cardiac regulation were studied using resting vagal tone and heart period measures obtained quarterly during infancy and at 2years in 158 breast-fed, 159 milk formula-fed, and 148 soy formula-fed infants. Both measures increased across time for all groups. Heart period was greater in boys than in girls-particularly in soy-fed infants. Higher vagal tone in girls than in boys was not strongly influenced by diet. At 1 and 2years measures differed among boys (soy-fed>breast-fed) but not among girls. Earlier slowing in breast-fed than in formula-fed infants in the rate of increase in vagal tone during infancy suggests that the timing of this developmental shift is sensitive to early infant diet. Finally, the findings do not indicate atypical development of cardiac activity in soy-fed infants that might be associated with estrogenic compounds in this formula.
authors.affiliation: Arkansas Children's Nutrition Center, 15 Children's Way, Little Rock, AR 72202, USA; Department of Pediatrics, University of Arkansas for Medical Sciences, 4301 W. Markham St., Little Rock, AR 72205, USA. Electronic address: pivikterry@uams.edu.
authors.forename: R T
authors.initials: RT
authors.lastname: Pivik
authors.forename: Aline
authors.initials: A
authors.lastname: Andres
authors.forename: Kevin B
authors.initials: KB
authors.lastname: Tennal
authors.forename: Yuyuan
authors.initials: Y
authors.lastname: Gu
authors.forename: Narain
authors.initials: N
authors.lastname: Armbya
authors.forename: Mario A
authors.initials: MA
authors.lastname: Cleves
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Badger
mesh_terms: D000367:Age Factors; D000704:Analysis of Variance; D002657:Child Development / Q000502:physiology*; D002675:Child, Preschool; D005260:Female; D006321:Heart / Q000254:growth & development*; D006801:Humans; D007223:Infant; D041943:Infant Formula / Q000008:administration & dosage*; D007227:Infant Nutritional Physiological Phenomena / Q000502:physiology*; D008137:Longitudinal Studies; D008297:Male; D012727:Sex Characteristics; D041942:Soy Milk / Q000008:administration & dosage; D014630:Vagus Nerve / Q000502:physiology*
keywords: Development; Gender; Heart period; Infant diet; Soy; Vagal tone