Self-reported dietary supplement use is confirmed by biological markers in the Norwegian Mother and Child Cohort Study (MoBa)

Background/ Aims: 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 nonsupplement users and to validate self- reported intake of dietary supplements in mid pregnancy. Method: 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 nonsupplement 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) 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). Conclusion: The biochemical indicators examined in this study confirmed differences in self- reported micronutrient intake between supplement and nonsupplement users for vitamin D, beta- carotene, folate, n - 3 fatty acids, flavonoids and iodine. Copyright (c) 2007 S. Karger AG, Basel