Relation of isoflavones and fiber intake in childhood to the timing of puberty.
BACKGROUND
It has been suggested that phytoestrogens and dietary fiber can affect puberty timing.


OBJECTIVE
We examined whether intake of isoflavone and fiber in healthy white children before their pubertal growth spurt [age at take-off (ATO)] was associated with puberty timing.


METHODS
Multivariate regression analyses were performed in 227 DONALD (DOrtmund Nutritional and Anthropometric Longitudinally Designed) Study participants with 3-d weighed dietary records and information on potential confounders at baseline (1 and 2 y before ATO). In a subsample (n = 111), urinary isoflavones were determined in 24-h urine samples by gas chromatography-mass spectrometry analysis. Puberty timing was examined by using ATO and chronologic ages at pubertal stage 2 for breast development (B2) or gonadal development, peak height velocity (PHV), and menarche or voice break.


RESULTS
Girls whose diet was in the highest dietary isoflavone tertile experienced Tanner stage 2 for breast development ap 0.7 y later and reached PHV ap 0.6 y later than did girls whose diet was in the lowest isoflavone tertile [age (95% CI) at B2: 10.7 y (10.4, 10.9 y) compared with 10.0 y ( 9.7, 10.3 y), respectively; P for trend = 0.04; age at PHV: 11.9 y (11.6, 12.2 y) compared with 11.3 y (11.0, 11.6 y), respectively; P for trend = 0.04; adjusted for body mass index z score and fiber intake]. In boys, dietary isoflavones were not associated with pubertal markers. Urinary isoflavone and dietary fiber intakes were not associated with pubertal markers.


CONCLUSIONS
Girls, but not boys, with higher prepubertal isoflavone intakes appear to enter puberty at a later age. Fiber intake in this sample of healthy white girls and boys was not relevant for puberty timing.
Cheng
Guo
G
Research Institute of Child Nutrition, Dortmund, Germany. cheng@fke-do.de
Remer
Thomas
T
Prinz-Langenohl
Reinhild
R
Blaszkewicz
Meinolf
M
Degen
Gisela H
GH
Buyken
Anette E
AE
D000367:Age Factors; D001827:Body Height / Q000502:physiology; D001940:Breast / Q000187:drug effects / Q000254:growth & development; D002648:Child; D004032:Diet; D015930:Diet Records; D004043:Dietary Fiber / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D007529:Isoflavones / Q000008:administration & dosage / Q000494:pharmacology* / Q000652:urine; D008137:Longitudinal Studies; D008297:Male; D008572:Menarche; D048789:Phytoestrogens / Q000008:administration & dosage / Q000494:pharmacology* / Q000652:urine; D011627:Puberty / Q000187:drug effects*; D012044:Regression Analysis; D012737:Sex Factors
D004043:Dietary Fiber; D007529:Isoflavones; D048789:Phytoestrogens