Plasma Alkylresorcinol Concentrations as a Novel Measure of Compliance to a Gluten‐Free Diet

Abstract

BackgroundMany celiac disease (CD) patients experience difficulties in adherence to a gluten‐free diet. Methods for testing compliance to a gluten‐free diet are costly and cumbersome.ObjectiveA simple biomarker of gluten intake is needed in a clinical setting and will be useful for epidemiological studies investigating wider effects of gluten intake. The aim was to evaluate plasma total alkylresorcinols (AR) concentrations as a measure of gluten intake.DesignThis randomized, controlled, cross‐over intervention study in 52 Danish adults with features of the metabolic syndrome compared eight weeks gluten‐rich and gluten‐poor diet separated by a wash‐out period of at least six weeks. We measured fasting plasma concentrations of AR to determine if they reflected differences in gluten intake. Additionally, we investigated in 118 Danish adults the cross‐sectional association between self‐reported gluten intake and plasma AR in this and a similar study at baseline.ResultsTotal plasma AR decreased more during the gluten‐poor period compared to the gluten‐rich period −124.8 (−156.5; −93.0) vs. −31.8 (−63.1; −0.4) nmol/L, respectively, p<0.001. Based on the plasma AR‐profile we built a classification tree to objectively determine compliance and found an overall misclassification error of participants of 3.9%. The cross‐sectional study showed a 5.6% (2.4; 8.9) increase in total plasma AR per 1 g‐increase in reported gluten intake (p<0.001).ConclusionWe propose plasma AR as a new tool to monitor compliance to a gluten‐free diet to support clinical work with CD, as well as to help investigations on the possible effects of gluten in the wider population.Support or Funding InformationFunded by the Innovation Fund Denmark, grant no. 0603‐00487B (11‐116163). Some intervention products were sponsored by Kohberg, Lantmännen, AXA, Wasa, Urtekram, Finax, and Doves Farm. MVL is part sponsored by Cereal Partners Worldwide with an unrestricted grant. The study sponsors played no role in the design, methods, data‐management and analysis or in the decision to publish.