title: A dietary biomarker approach captures compliance and cardiometabolic effects of a healthy Nordic diet in individuals with metabolic syndrome.
abstract: Assessment of compliance with dietary interventions is necessary to understand the observed magnitude of the health effects of the diet per se. To avoid reporting bias, different dietary biomarkers (DBs) could be used instead of self-reported data. However, few studies investigated a combination of DBs to assess compliance and its influence on cardiometabolic risk factors. The objectives of this study were to use a combination of DBs to assess compliance and to investigate how a healthy Nordic diet (ND) influences cardiometabolic risk factors in participants with high apparent compliance compared with the whole study population. From a recently conducted isocaloric randomized trial, SYSDIET (Systems Biology in Controlled Dietary Interventions and Cohort Studies), in 166 individuals with metabolic syndrome, several DBs were assessed to reflect different key components of the ND: canola oil (serum phospholipid α-linolenic acid), fatty fish [eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)], vegetables (plasma β-carotene), and whole grains (plasma alkylresorcinols). High-fat dairy intake (expectedly low in the ND) was reflected by serum pentadecanoic acid. All participants with biomarker data (n = 154) were included in the analyses. Biomarkers were combined by using a biomarker rank score (DB score) and principal component analysis (PCA). The DB score was then used to assess compliance. During the intervention, median concentrations of alkylresorcinols, α-linolenic acid, EPA, and DHA were >25% higher in the ND individuals than in the controls (P < 0.05), whereas median concentrations of pentadecanoic acid were 14% higher in controls (P < 0.05). Median DB score was 57% higher in the ND than in controls (P < 0.001) during the intervention, and participants were ranked similarly by DB score and PCA score. Overall, estimates of group difference in cardiometabolic effects generally appeared to be greater among compliant participants than in the whole study population (e.g., estimates of treatment effects on blood pressure and lipoproteins were ∼1.5- to 2-fold greater in the most compliant participants), suggesting that poor compliance attenuated the dietary effects. With adequate consideration of their limitations, DB combinations (e.g., DB score) could be useful for assessing compliance in intervention studies investigating cardiometabolic effects of healthy dietary patterns. The study was registered at clinicaltrials.gov as NCT00992641.
authors: Department of Public Health and Caring Sciences, Clinical Nutrition and Metabolism, Uppsala University, Uppsala, Sweden.
authors: Matti
authors: M
authors: Marklund
authors: Unit for Nutrition Research, Landspitali, The National University of Iceland, Reykjavík, Iceland Faculty of Food Science and Nutrition and School of Health Sciences, University of Iceland, Reykjavík, Iceland.
authors: Ola K
authors: OK
authors: Magnusdottir
authors: Department of Public Health and Caring Sciences, Clinical Nutrition and Metabolism, Uppsala University, Uppsala, Sweden.
authors: Fredrik
authors: F
authors: Rosqvist
authors: Biomedical Nutrition, Pure and Applied Biochemistry, Lund University, Lund, Sweden.
authors: Lieselotte
authors: L
authors: Cloetens
authors: Department of Food Science, BioCenter, Swedish University of Agricultural Sciences, Uppsala, Sweden.
authors: Rikard
authors: R
authors: Landberg
authors: Institute of Public Health and Clinical Nutrition, University of Eastern Finland, Kuopio, Finland VTT Technical Research Centre of Finland, Espoo, Finland.
authors: Marjukka
authors: M
authors: Kolehmainen
authors: Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark.
authors: Lea
authors: L
authors: Brader
authors: Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark.
authors: Kjeld
authors: K
authors: Hermansen
authors: Institute of Public Health and Clinical Nutrition, University of Eastern Finland, Kuopio, Finland VTT Technical Research Centre of Finland, Espoo, Finland.
authors: Kaisa S
authors: KS
authors: Poutanen
authors: Institute of Biomedicine, Department of Physiology and Medical Research Center Oulu and.
authors: Karl-Heinz
authors: KH
authors: Herzig
authors: Institute of Clinical Medicine, Department of Internal Medicine, Biocenter Oulu, University of Oulu, Oulu, Finland Department of Internal Medicine, Oulu University Hospital, Oulu, Finland.
authors: Janne
authors: J
authors: Hukkanen
authors: Institute of Clinical Medicine, Department of Internal Medicine, Biocenter Oulu, University of Oulu, Oulu, Finland Department of Internal Medicine, Oulu University Hospital, Oulu, Finland.
authors: Markku J
authors: MJ
authors: Savolainen
authors: Department of Nutrition, Exercise, and Sports, University of Copenhagen, Frederiksberg, Denmark.
authors: Lars O
authors: LO
authors: Dragsted
authors: Institute of Public Health and Clinical Nutrition, University of Eastern Finland, Kuopio, Finland Institute of Clinical Medicine, Internal Medicine and.
authors: Ursula
authors: U
authors: Schwab
authors: Institute of Public Health and Clinical Nutrition, University of Eastern Finland, Kuopio, Finland.
authors: Jussi
authors: J
authors: Paananen
authors: Institute of Public Health and Clinical Nutrition, University of Eastern Finland, Kuopio, Finland Research Unit, Kuopio University Hospital, Kuopio, Finland.
authors: Matti
authors: M
authors: Uusitupa
authors: Biomedical Nutrition, Pure and Applied Biochemistry, Lund University, Lund, Sweden.
authors: Björn
authors: B
authors: Åkesson
authors: Unit for Nutrition Research, Landspitali, The National University of Iceland, Reykjavík, Iceland Faculty of Food Science and Nutrition and School of Health Sciences, University of Iceland, Reykjavík, Iceland.
authors: Inga
authors: I
authors: Thorsdottir
authors: Department of Public Health and Caring Sciences, Clinical Nutrition and Metabolism, Uppsala University, Uppsala, Sweden ulf.riserus@pubcare.uu.se.
authors: Ulf
authors: U
authors: Risérus
mesh_terms: D001053:Apolipoproteins / Q000097:blood; D015415:Biomarkers / Q000097:blood*; D001794:Blood Pressure; D015992:Body Mass Index; D002318:Cardiovascular Diseases / Q000097:blood / Q000150:complications / Q000517:prevention & control*; D002784:Cholesterol / Q000097:blood; D004032:Diet; D004281:Docosahexaenoic Acids / Q000097:blood; D002523:Edible Grain / Q000737:chemistry; D015118:Eicosapentaenoic Acid / Q000097:blood; D005227:Fatty Acids / Q000097:blood; D005229:Fatty Acids, Monounsaturated / Q000737:chemistry; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood* / Q000150:complications / Q000178:diet therapy*; D008875:Middle Aged; D010349:Patient Compliance; D010743:Phospholipids / Q000097:blood; D000074262:Rapeseed Oil; D014280:Triglycerides / Q000097:blood; D014675:Vegetables / Q000737:chemistry; D017962:alpha-Linolenic Acid / Q000097:blood; D019207:beta Carotene / Q000097:blood
chemical_list: D001053:Apolipoproteins; D015415:Biomarkers; D005227:Fatty Acids; D005229:Fatty Acids, Monounsaturated; D010743:Phospholipids; D000074262:Rapeseed Oil; D014280:Triglycerides; D019207:beta Carotene; D017962:alpha-Linolenic Acid; D004281:Docosahexaenoic Acids; D002784:Cholesterol; D015118:Eicosapentaenoic Acid; C117025:pentadecanoic acid