title: Plasma Alkylresorcinols Reflect Gluten Intake and Distinguish between Gluten-Rich and Gluten-Poor Diets in a Population at Risk of Metabolic Syndrome.
abstract: BACKGROUND
  Many patients with celiac disease experience difficulties in adherence to a gluten-free diet. Methods for testing compliance to a gluten-free diet are costly and cumbersome. Thus, a simple biomarker of gluten intake is needed in a clinical setting and will be useful for epidemiologic studies investigating wider effects of gluten intake.
  
  
  OBJECTIVE
  The aim was to evaluate plasma total alkylresorcinol concentrations as a measure of gluten intake.
  
  
  METHODS
  In this randomized, controlled, crossover intervention study in 52 Danish adults with features of the metabolic syndrome, we compared 8 wk of a gluten-rich and gluten-poor diet separated by a washout period of ≥6 wk. We measured fasting plasma concentrations of alkylresorcinols to determine if they reflected differences in gluten intake as a secondary outcome of the original study. In addition, we investigated in 118 Danish adults the cross-sectional association between self-reported gluten intake and plasma alkylresorcinols in the same and a similar study at baseline. We used mixed-model ANCOVA for examining treatment effects, a classification tree to determine compliance to the gluten-poor diet, and linear regression models for examining baseline correlation between plasma alkylresorcinol concentrations and gluten intake.
  
  
  RESULTS
  Plasma total alkylresorcinols decreased more during the gluten-poor period (geometric mean: -124.8 nmol/L; 95% CI: -156.5, -93.0 nmol/L) than in the gluten-rich period (geometric mean: -31.8 nmol/L; 95% CI: -63.1, -0.4 nmol/L) (P < 0.001). On the basis of the plasma alkylresorcinol profile, we built a classification tree to objectively determine compliance and found an overall participant misclassification error of 3.9%. In the cross-sectional study we found a 5.6% (95% CI: 2.4%, 8.9%) increase in plasma total alkylresorcinols per 1-g increase in reported gluten intake (P < 0.001).
  
  
  CONCLUSIONS
  We propose the use of plasma alkylresorcinols to monitor compliance to a gluten-free diet as well as to help investigations into the possible effects of gluten in the wider population. This trial was registered at www.clinicaltrials.gov as NCT017119913 and NCT01731366.
authors.affiliation: Department of Nutrition, Exercise, and Sports, Faculty of Science, University of Copenhagen, Frederiksberg, Denmark; Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden; madslind@nexs.ku.dk.
authors.forename: Mads V
authors.identifier: http://orcid.org/0000-0002-4999-1218
authors.initials: MV
authors.lastname: Lind
authors.affiliation: The Novo Nordisk Foundation Center for Basic Metabolic Research, Section of Metabolic Genetics, Faculty of Health and Medical Sciences, and.
authors.forename: Mia L
authors.initials: ML
authors.lastname: Madsen
authors.affiliation: QD-Research Unit and Department of Gastroenterology, Herlev and Gentofte Hospital, University of Copenhagen, Copenhagen, Denmark; and.
authors.forename: Jüri J
authors.initials: JJ
authors.lastname: Rumessen
authors.affiliation: The Novo Nordisk Foundation Center for Basic Metabolic Research, Section of Metabolic Genetics, Faculty of Health and Medical Sciences, and Steno Diabetes Center, Gentofte, Denmark.
authors.forename: Henrik
authors.initials: H
authors.lastname: Vestergaard
authors.affiliation: The Novo Nordisk Foundation Center for Basic Metabolic Research, Section of Metabolic Genetics, Faculty of Health and Medical Sciences, and.
authors.forename: Rikke J
authors.initials: RJ
authors.lastname: Gøbel
authors.affiliation: The Novo Nordisk Foundation Center for Basic Metabolic Research, Section of Metabolic Genetics, Faculty of Health and Medical Sciences, and.
authors.forename: Torben
authors.initials: T
authors.lastname: Hansen
authors.affiliation: Department of Nutrition, Exercise, and Sports, Faculty of Science, University of Copenhagen, Frederiksberg, Denmark.
authors.forename: Lotte
authors.initials: L
authors.lastname: Lauritzen
authors.affiliation: The Novo Nordisk Foundation Center for Basic Metabolic Research, Section of Metabolic Genetics, Faculty of Health and Medical Sciences, and.
authors.forename: Oluf B
authors.initials: OB
authors.lastname: Pedersen
authors.affiliation: Department of Nutrition, Exercise, and Sports, Faculty of Science, University of Copenhagen, Frederiksberg, Denmark.
authors.forename: Mette
authors.initials: M
authors.lastname: Kristensen
authors.affiliation: Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden.
authors.forename: Alastair B
authors.identifier: http://orcid.org/0000-0002-9585-0141
authors.initials: AB
authors.lastname: Ross
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000378:metabolism; D001794:Blood Pressure; D015992:Body Mass Index; D002446:Celiac Disease / Q000097:blood / Q000178:diet therapy; D008076:Cholesterol, HDL / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood; D018592:Cross-Over Studies; D003430:Cross-Sectional Studies; D003718:Denmark; D055050:Diet, Gluten-Free; D002149:Energy Intake; D005260:Female; D005983:Glutens / Q000008:administration & dosage* / Q000097:blood; D006801:Humans; D016014:Linear Models; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood*; D008875:Middle Aged; D010349:Patient Compliance; D012118:Resorcinols / Q000097:blood*; D012307:Risk Factors; D057566:Self Report; D014280:Triglycerides / Q000097:blood; D055105:Waist Circumference; D055815:Young Adult
chemical_list: D015415:Biomarkers; D001786:Blood Glucose; D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D012118:Resorcinols; D014280:Triglycerides; D005983:Glutens
keywords: biomarkers; celiac disease; coeliac disease; gluten intolerance; gluten sensitivity; gluten-free diet; gluten-related disorders