Fig. 1

Scheme of the currently suggested BFIRev research methodology. The “Guidelines for Biomarker of Food Intake Reviews (BFIRev)” 4-step procedure is designed for listing candidate food or food group biomarkers (Table I) while also retrieving important information for biomarker validation, whenever it is available. BFIRev is shown here as a decision tree listing the most important steps. The questions in the diamonds should be assessed by at least two researchers independently