title: Twenty-four-hour urinary thiamine as a biomarker for the assessment of thiamine intake.
abstract: OBJECTIVE
  To investigate 24-h urinary thiamine as a potential biomarker for thiamine intake for use in validation studies to assess the validity of dietary intake data collected by self-reporting dietary methods.
  
  
  METHODS
  Seven male and six female healthy participants living for 30 days in a metabolic suite under strictly controlled conditions consuming their usual diet as assessed beforehand from four consecutive 7-day food diaries kept at home. During the 30-day study, all 24-h urine specimens were collected, validated for their completeness and analysed for thiamine.
  
  
  RESULTS
  Thirty-day mean (+/-s.d.) calculated thiamine intake was 2.22+/-0.55 mg/day. Thirty-day mean (+/-s.d.) urinary excretion of thiamine was 526.5+/-193.0 microg/day (24.7+/-8.10% of intake). There was a highly significant correlation between individuals' 30-day means of thiamine intake and their mean excretion level (r=0.720; P=0.006), where 1 mg of thiamine intake predicted 268.2 microg of thiamine in urine. The correlations between intake and excretion remained significant when measurement from a single 24-h urine collection was used (r=0.56).
  
  
  CONCLUSIONS
  Twenty-four-hour urinary thiamine can be used as a concentration biomarker for thiamine intake in dietary validation studies.
authors.affiliation: MRC Dunn Human Nutrition Unit, University of Cambridge, Cambridge, UK.
authors.forename: N
authors.initials: N
authors.lastname: Tasevska
authors.forename: S A
authors.initials: SA
authors.lastname: Runswick
authors.forename: A
authors.initials: A
authors.lastname: McTaggart
authors.forename: S A
authors.initials: SA
authors.lastname: Bingham
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000652:urine; D004032:Diet; D015930:Diet Records; D005260:Female; D005504:Food Analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D015596:Nutrition Assessment; D013831:Thiamine / Q000008:administration & dosage / Q000652:urine*; D055815:Young Adult
chemical_list: D015415:Biomarkers; D013831:Thiamine