title: Twenty-four-hour urinary water-soluble vitamin levels correlate with their intakes in free-living Japanese schoolchildren.
abstract: OBJECTIVE
  To examine the association between 24 h urinary water-soluble vitamin levels and their intakes in free-living Japanese schoolchildren.
  
  
  METHODS
  All foods consumed for four consecutive days were recorded accurately by a weighed food record. A single 24 h urine sample was collected on the fourth day, and the urinary levels of water-soluble vitamins were measured.
  
  
  METHODS
  An elementary school in Inazawa City, Japan.
  
  
  METHODS
  A total of 114 healthy, free-living, Japanese elementary-school children aged 10-12 years.
  
  
  RESULTS
  The urinary level of each water-soluble vitamin was correlated positively to its mean intake in the past 2-4 d (vitamin B1: r = 0·42, P < 0·001; vitamin B2: r = 0·43, P < 0·001; vitamin B6: r = 0·49, P < 0·001; niacin: r = 0·32, P < 0·001; niacin equivalents: r = 0·32, P < 0·001; pantothenic acid: r = 0·32, P < 0·001; folic acid: r = 0·27, P < 0·01; vitamin C: r = 0·39, P < 0.001), except for vitamin B12 (r = 0·10, P = NS). Estimated mean intakes of water-soluble vitamins calculated using urinary levels and recovery rates were 97-102 % of their 3 d mean intake, except for vitamin B12 (79 %).
  
  
  CONCLUSIONS
  The results show that urinary levels of water-soluble vitamins, except for vitamin B12, reflected their recent intakes in free-living Japanese schoolchildren and could be used as a potential biomarker to estimate mean vitamin intake.
authors.affiliation: Department of Food Science and Nutrition, School of Human Cultures, The University of Shiga Prefecture, 2500 Hassaka, Hikone, Shiga 522-8533, Japan.
authors.forename: Tomiko
authors.initials: T
authors.lastname: Tsuji
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Fukuwatari
authors.forename: Satoshi
authors.initials: S
authors.lastname: Sasaki
authors.forename: Katsumi
authors.initials: K
authors.lastname: Shibata
mesh_terms: D015415:Biomarkers / Q000652:urine; D002648:Child; D003430:Cross-Sectional Studies; D015930:Diet Records; D005260:Female; D006801:Humans; D007564:Japan; D008297:Male; D012574:Schools; D012995:Solubility; D013334:Students; D016482:Urinalysis / Q000706:statistics & numerical data*; D014815:Vitamins / Q000008:administration & dosage* / Q000652:urine*
chemical_list: D015415:Biomarkers; D014815:Vitamins