title: Self-reported dietary supplement use is confirmed by biological markers in the Norwegian Mother and Child Cohort Study (MoBa).
abstract: OBJECTIVE
  A food frequency questionnaire (FFQ) and a database for dietary supplements were developed for use in the Norwegian Mother and Child Cohort Study (MoBa). The aim of the present study was to investigate the relation between reported use and biomarkers in supplement and non-supplement users and to validate self-reported intake of dietary supplements in mid pregnancy.
  
  
  METHODS
  120 women were recruited from MoBa, and 119 subjects completed the MoBa FFQ and a 4-day weighed food diary. Information on supplement use was collected by both methods. Venous blood specimens and 24-hour urine samples were obtained for measurement of dietary biomarkers.
  
  
  RESULTS
  Biomarker concentration/excretion and intake differed significantly between supplement and non-supplement users for vitamin D, carotenoids, folate, the n-6/n-3 fatty acid ratio and iodine (p < 0.05 for all variables). Flavonoid excretion was higher in flavonoid-supplement users (p < 0.05). Significant correlations between total dietary intake (food and supplements) and biomarker concentration/excretion were found for vitamin D (r = 0.45, p < 0.001), folate (r = 0.26, p = 0.005), the n-6/n-3 fatty acid ratio (r = 0.36, p < 0.001) and iodine (r = 0.42, p < 0.001).
  
  
  CONCLUSIONS
  The biochemical indicators examined in this study confirmed differences in self-reported micronutrient intake between supplement and non-supplement users for vitamin D, beta-carotene, folate, n-3 fatty acids, flavonoids and iodine.
authors.affiliation: Division of Environmental Medicine, Department of Food Toxicology, Norwegian Institute of Public Health, Oslo, Norway. anne.lise.brantsaeter@fhi.no
authors.forename: Anne Lise
authors.initials: AL
authors.lastname: Brantsaeter
authors.forename: Margaretha
authors.initials: M
authors.lastname: Haugen
authors.forename: Tor-Arne
authors.initials: TA
authors.lastname: Hagve
authors.forename: Lage
authors.initials: L
authors.lastname: Aksnes
authors.forename: Salka E
authors.initials: SE
authors.lastname: Rasmussen
authors.forename: Kåre
authors.initials: K
authors.lastname: Julshamn
authors.forename: Jan
authors.initials: J
authors.lastname: Alexander
authors.forename: Helle Margrete
authors.initials: HM
authors.lastname: Meltzer
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood / Q000652:urine; D015331:Cohort Studies; D015930:Diet Records; D004034:Diet Surveys; D019587:Dietary Supplements / Q000706:statistics & numerical data*; D005231:Fatty Acids, Unsaturated / Q000008:administration & dosage* / Q000097:blood / Q000652:urine; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage* / Q000097:blood / Q000652:urine; D006801:Humans; D007455:Iodine / Q000008:administration & dosage / Q000097:blood / Q000652:urine*; D009664:Norway; D011247:Pregnancy; D011446:Prospective Studies; D012650:Self Disclosure; D011795:Surveys and Questionnaires; D014807:Vitamin D / Q000008:administration & dosage* / Q000097:blood / Q000652:urine; D014815:Vitamins / Q000008:administration & dosage / Q000097:blood / Q000652:urine
chemical_list: D015415:Biomarkers; D005231:Fatty Acids, Unsaturated; D014815:Vitamins; D014807:Vitamin D; D005492:Folic Acid; D007455:Iodine