Validation of biomarkers of food intake-critical assessment of candidate biomarkers

FoodBAll is a project funded by the BioNH call (grant number 529051002) under the Joint Programming Initiative, "A Healthy Diet for a Healthy Life." The project is funded nationally by the respective Research Councils; the work was funded in part by a grant from the Danish Innovation Foundation (#4203-00002B) and a Semper Ardens grant from the Carlsberg Foundation to LOD; a postdoc grant from the University of Rome La Sapienza ("Borsa di studio per la frequenza di corsi o attivita di perfezionamento all'estero" erogata ai sensi della legge 398/89) to GP; the Swiss National Science Foundation (40HD40_160618) in the frame of the national research program "Healthy nutrition and sustainable food protection" (NRP69) to GV; a grant from the China Scholarship Council (201506350127) to QG; a grant from Science Foundation Ireland (SFI 14/JPI-HDHL/B3076) and ERC (647783) to LB; a grant from the Canadian Institutes of Health Research (CIHR) to DSW; a grant from the Agence Nationale de la Recherche (#ANR-14-HDHL-0002-02) to CM; a grant from the Spanish National Grants from the Ministry of Economy and Competitiveness (MINECO) (PCIN-2014-133-MINECO Spain), an award of 2014SGR1566 from the Generalitat de Catalunya's Agency AGAUR, and fundings from CIBERFES (co-funded by the FEDER Program from EU) to CAL; a grant from the Italian Ministry of Agriculture, Food and Forestry Policies (MiPAAF) within the JPI-HDHL (MIUR D.M. 115/2013) to HA.

anglais. Biomarkers of food intake (BFIs) are a promising tool for limiting misclassification in nutrition research where more subjective dietary assessment instruments are used. They may also be used to assess compliance to dietary guidelines or to a dietary intervention. Biomarkers therefore hold promise for direct and objective measurement of food intake. However, the number of comprehensively validated biomarkers of food intake is limited to just a few. Many new candidate biomarkers emerge from metabolic profiling studies and from advances in food chemistry. Furthermore, candidate food intake biomarkers may also be identified based on extensive literature reviews such as described in the guidelines for Biomarker of Food Intake Reviews (BFIRev). To systematically and critically assess the validity of candidate biomarkers of food intake, it is necessary to outline and streamline an optimal and reproducible validation process. A consensus-based procedure was used to provide and evaluate a set of the most important criteria for systematic validation of BFIs. As a result, a validation procedure was developed including eight criteria, plausibility, dose-response, time-response, robustness, reliability, stability, analytical performance, and inter-laboratory reproducibility. The validation has a dual purpose: (1) to estimate the current level of validation of candidate biomarkers of food intake based on an objective and systematic approach and (2) to pinpoint which additional studies are needed to provide full validation of each candidate biomarker of food intake. This position paper on biomarker of food intake validation outlines the second step of the BFIRev procedure but may also be used as such for validation of new candidate biomarkers identified, e.g., in food metabolomic studies.