title: Normal distribution of urinary polyphenol excretion among Egyptian males 7-14 years old and changes following nutritional intervention with tomato juice (Lycopersicon esculentum).
abstract: BACKGROUND
  The urinary flavonoids are considered a reliable biomarker for the intake of polyphenol-rich foods.
  
  
  OBJECTIVE
  To assess the normal distribution of urinary polyphenol [PP] excretion among healthy male children and adolescents on a typical Egyptian diet. To follow up the impact of nutritional intervention with tomato juice on the urinary excretion of [PP].
  
  
  METHODS
  Forty-nine male subjects 7-14 years old collected a 24-h urine sample and filled a dietary record during a 7-day period. A daily serving of 230 g fresh tomato juice was followed for 18 days in a subgroup. Total urinary [PP] excretions were measured before and after termination of the intervention program. The total urinary [PP] was analyzed after a clean-up solid-phase extraction step by the Folin-Ciocalteu reagent in the 96 micro plates. The results were expressed as gallic acid equivalents (GAE).
  
  
  RESULTS
  The urinary [PP] excretion averaged 48.6+/-5.5 mg GAE/24 h, equivalent to 89.5+/-8.4 mg GAE/g creatinine. The mean urinary [PP] excretion increased significantly (P<0.05) following the intervention with tomato juice (287.4+/-64.3 mg GAE/g creatinine) compared with the respective mean baseline level (94.5+/-8.92 mg GAE/g creatinine).
  
  
  CONCLUSIONS
  Clinical laboratory reference limits for urinary polyphenols are presented for Egyptian male children and adolescents. Measuring the urinary polyphenol excretion proved a good biomarker for the dietary polyphenol intake and the results demonstrated that tomato [PP] was highly bioavailable in the human body.
authors.affiliation: Department of Nutrition and Food Science, National Research Center, 12311 Giza-Dokki, Elbohous Street, Egypt. egcairouw@yahoo.com
authors.forename: Laila
authors.initials: L
authors.lastname: Hussein
authors.forename: Alexander
authors.initials: A
authors.lastname: Medina
authors.forename: Ana
authors.initials: A
authors.lastname: Barrionnevo
authors.forename: Rosa M
authors.initials: RM
authors.lastname: Lammuela-Raventos
authors.forename: Cristina
authors.initials: C
authors.lastname: Andres-Lacueva
mesh_terms: D000293:Adolescent; D000975:Antioxidants / Q000378:metabolism*; D001628:Beverages; D015415:Biomarkers / Q000652:urine; D002648:Child; D003404:Creatinine / Q000652:urine; D004032:Diet; D004534:Egypt; D005419:Flavonoids / Q000652:urine*; D006801:Humans; D018551:Solanum lycopersicum / Q000737:chemistry*; D008297:Male; D010636:Phenols / Q000652:urine*; D059808:Polyphenols
chemical_list: D000975:Antioxidants; D015415:Biomarkers; D005419:Flavonoids; D010636:Phenols; D059808:Polyphenols; D003404:Creatinine