title: Plasma phospholipid pentadecanoic acid, EPA, and DHA, and the frequency of dairy and fish product intake in young children.
abstract: BACKGROUND
  There is a lack of studies comparing dietary assessment methods with the biomarkers of fatty acids in children.
  
  
  OBJECTIVE
  The objective was to evaluate the suitability of a food frequency questionnaire (FFQ) to rank young children according to their intake of dairy and fish products by comparing food frequency estimates to the plasma phospholipid fatty acids pentadecanoic acid, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA).
  
  
  METHODS
  Cross-sectional data for the present study were derived from the prospective cohort 'Environmental Triggers of Type 1 Diabetes Study'. Infants were recruited from the Norwegian general population during 2001-2007. One hundred and ten (age 3-10 years) children had sufficient volumes of plasma and FFQ filled in within 2 months from blood sampling and were included in this evaluation study. The quantitative determination of plasma phospholipid fatty acids was done by fatty acid methyl ester analysis. The association between the frequency of dairy and fish product intake and the plasma phospholipid fatty acids was assessed by a Spearman correlation analysis and by investigating whether participants were classified into the same quartiles of distribution.
  
  
  RESULTS
  Significant correlations were found between pentadecanoic acid and the intake frequency of total dairy products (r=0.29), total fat dairy products (r=0.39), and cheese products (r=0.36). EPA and DHA were significantly correlated with the intake frequency of oily fish (r=0.26 and 0.37, respectively) and cod liver/fish oil supplements (r=0.47 for EPA and r=0.50 DHA). To a large extent, the FFQ was able to classify individuals into the same quartile as the relevant fatty acid biomarker.
  
  
  CONCLUSIONS
  The present study suggests that, when using the plasma phospholipid fatty acids pentadecanoic acid, EPA, and DHA as biomarkers, the FFQ used in young children showed a moderate capability to rank the intake frequency of dairy products with a high-fat content and cod liver/fish oil supplements.
authors.affiliation: Department of Pediatric Research, Oslo University Hospital, Rikshospitalet, Oslo, Norway.|Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.|Division of Epidemiology, Norwegian Institute of Public Health, Oslo, Norway; n.a.lund@medisin.uio.no.
authors.forename: Nicolai A
authors.initials: NA
authors.lastname: Lund-Blix
authors.affiliation: Department of Pediatric Research, Oslo University Hospital, Rikshospitalet, Oslo, Norway.
authors.forename: Kjersti S
authors.initials: KS
authors.lastname: Rønningen
authors.affiliation: Division of Epidemiology, Norwegian Institute of Public Health, Oslo, Norway.
authors.forename: Håkon
authors.initials: H
authors.lastname: Bøås
authors.affiliation: Division of Epidemiology, Norwegian Institute of Public Health, Oslo, Norway.
authors.forename: German
authors.initials: G
authors.lastname: Tapia
authors.affiliation: Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.
authors.forename: Lene F
authors.initials: LF
authors.lastname: Andersen
keywords: biomarkers; dietary assessment; fatty acids; food frequency questionnaire; plasma phospholipids