title: Diet-induced changes in iron and n-3 fatty acid status and associations with cognitive performance in 8-11-year-old Danish children: secondary analyses of the Optimal Well-Being, Development and Health for Danish Children through a Healthy New Nordic Diet School Meal Study.
abstract: Fe and n-3 long-chain PUFA (n-3 LCPUFA) have both been associated with cognition, but evidence remains inconclusive in well-nourished school-aged children. In the Optimal Well-Being, Development and Health for Danish Children through a Healthy New Nordic Diet (OPUS) School Meal Study, the 3-month intervention increased reading performance, inattention, impulsivity and dietary intake of fish and Fe. This study investigated whether the intervention influenced n-3 LCPUFA and Fe status and, if so, explored how these changes correlated with the changes in cognitive performance. The study was a cluster-randomised cross-over trial comparing school meals with packed lunch (control). At baseline and after each treatment, we measured serum ferritin, whole-blood n-3 LCPUFA and Hb, and performance in reading, mathematics and d2-test of attention. Data were analysed using mixed models (n 726) and principal component analysis of test performances (n 644), which showed two main patterns: 'school performance' and 'reading comprehension'. The latter indicated that children with good reading comprehension were also more inattentive and impulsive (i.e. higher d2-test error%). The intervention improved 'school performance' (P=0·015), 'reading comprehension' (P=0·043) and EPA+DHA status 0·21 (95% CI 0·15, 0·27) w/w % (P<0·001), but it did not affect serum ferritin or Hb. At baseline, having small Fe stores was associated with poorer 'school performance' in girls, but with better 'reading comprehension' in both boys and girls. Both baseline EPA+DHA status and the intervention-induced increase in EPA+DHA status was positively associated with 'school performance', suggesting that n-3 LCPUFA could potentially explain approximately 20 % of the intervention effect. These exploratory associations indicate that increased fish intake might explain some of the increase in reading performance and inattention in the study.
authors.affiliation: 1Department of Nutrition Exercise and Sports,University of Copenhagen,Rolighedsvej 26,1958 Frederiksberg C,Denmark.
authors.forename: Louise Bergmann
authors.initials: LB
authors.lastname: Sørensen
authors.affiliation: 1Department of Nutrition Exercise and Sports,University of Copenhagen,Rolighedsvej 26,1958 Frederiksberg C,Denmark.
authors.forename: Camilla Trab
authors.initials: CT
authors.lastname: Damsgaard
authors.affiliation: 1Department of Nutrition Exercise and Sports,University of Copenhagen,Rolighedsvej 26,1958 Frederiksberg C,Denmark.
authors.forename: Stine-Mathilde
authors.initials: SM
authors.lastname: Dalskov
authors.affiliation: 1Department of Nutrition Exercise and Sports,University of Copenhagen,Rolighedsvej 26,1958 Frederiksberg C,Denmark.
authors.forename: Rikke Agnete
authors.initials: RA
authors.lastname: Petersen
authors.affiliation: 2Centre for Strategic Research in Education and Competence,Aarhus University,Tuborgvej 164,2400 København NV,Denmark.
authors.forename: Niels
authors.initials: N
authors.lastname: Egelund
authors.affiliation: 2Centre for Strategic Research in Education and Competence,Aarhus University,Tuborgvej 164,2400 København NV,Denmark.
authors.forename: Camilla Brørup
authors.initials: CB
authors.lastname: Dyssegaard
authors.affiliation: 3Department of Kinesiology,University of Waterloo,200 University Avenue West,Waterloo, ON,Canada N2L 3G1.
authors.forename: Ken D
authors.initials: KD
authors.lastname: Stark
authors.affiliation: 4Division of Nutrition,The National Food Institute,Technical University of Denmark,Mørkhøj Bygade 19,2860 Søborg,Denmark.
authors.forename: Rikke
authors.initials: R
authors.lastname: Andersen
authors.affiliation: 4Division of Nutrition,The National Food Institute,Technical University of Denmark,Mørkhøj Bygade 19,2860 Søborg,Denmark.
authors.forename: Inge
authors.initials: I
authors.lastname: Tetens
authors.affiliation: 1Department of Nutrition Exercise and Sports,University of Copenhagen,Rolighedsvej 26,1958 Frederiksberg C,Denmark.
authors.forename: Arne
authors.initials: A
authors.lastname: Astrup
authors.affiliation: 1Department of Nutrition Exercise and Sports,University of Copenhagen,Rolighedsvej 26,1958 Frederiksberg C,Denmark.
authors.forename: Kim Fleisher
authors.initials: KF
authors.lastname: Michaelsen
authors.affiliation: 1Department of Nutrition Exercise and Sports,University of Copenhagen,Rolighedsvej 26,1958 Frederiksberg C,Denmark.
authors.forename: Lotte
authors.initials: L
authors.lastname: Lauritzen
mesh_terms: D000818:Animals; D002648:Child; D003071:Cognition / Q000502:physiology*; D018592:Cross-Over Studies; D003718:Denmark; D004032:Diet; D004521:Educational Measurement; D015525:Fatty Acids, Omega-3 / Q000097:blood*; D005260:Female; D005293:Ferritins / Q000097:blood; D005399:Fishes; D005522:Food Services; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D007501:Iron / Q000378:metabolism*; D019266:Iron, Dietary / Q000008:administration & dosage; D062409:Lunch; D008297:Male; D008433:Mathematics; D009752:Nutritional Status; D011932:Reading; D012574:Schools
chemical_list: D015525:Fatty Acids, Omega-3; D006454:Hemoglobins; D019266:Iron, Dietary; D005293:Ferritins; D007501:Iron
keywords:     n-3 PUFA; CP concentration performance; CRP C-reactive protein; Cognitive performance; ID Fe deficiency; IDA ID with anaemia; Iron; PCA principal component analysis; RCT randomised controlled trial; School meals; School performance; n-3 LCPUFA n-3 long-chain PUFA