title: Isoflavones from soya foods are more bioavailable in children than adults.
abstract: The purpose of the present study was to determine whether children experience a higher systemic exposure to isoflavonoids when consuming a body weight-adjusted dose of soya compared with adults. Forty study participants were recruited from a local Waldorf school, including twenty-one children and nineteen adults. Participants collected a baseline urine sample and ate immediately thereafter a body weight-adjusted dose of soya nuts (15 g/54.4 kg equivalent to 0.615 (SD 0.036) mg total isoflavones/kg) followed by a 12 h urine collection. Nineteen children and eighteen adults completed the protocol correctly (fourteen child-parent pairs). Children, compared with adults, showed a statistically significant (P < 0.05 by unpaired t test) higher urinary isoflavone excretion rate for daidzein (+39%), genistein (+44%), all non-metabolites (daidzein + genistein + glycitein; +41%) and total isoflavonoids (+32%). Isoflavones are more bioavailable in children v. adults. Urine is an excellent medium to determine systemic isoflavone exposure in children due to its non-invasiveness and high compliance, in particular when collected overnight; it also allows evaluation of completeness of specimen collection.
authors.affiliation: Cancer Research Center of Hawai'i, Cancer Prevention and Control Program and Kapi'olani Medical Center for Women and Children, Honolulu, HI, USA.
authors.forename: Brunhild M
authors.initials: BM
authors.lastname: Halm
authors.forename: Leslie A
authors.initials: LA
authors.lastname: Ashburn
authors.forename: Adrian A
authors.initials: AA
authors.lastname: Franke
mesh_terms: D000293:Adolescent; D000328:Adult; D000375:Aging / Q000652:urine*; D001682:Biological Availability; D001835:Body Weight / Q000502:physiology; D002648:Child; D002664:Child Nutritional Physiological Phenomena / Q000502:physiology*; D002675:Child, Preschool; D005260:Female; D019833:Genistein / Q000008:administration & dosage / Q000737:chemistry / Q000652:urine; D006801:Humans; D007529:Isoflavones / Q000008:administration & dosage / Q000737:chemistry / Q000652:urine*; D008297:Male; D045730:Soy Foods / Q000032:analysis*
chemical_list: D007529:Isoflavones; C004742:daidzein; C086566:glycitein; D019833:Genistein