ABSTRACT
This chapter gives an overview of current knowledge on dietary biomarkers, used as indicators of dietary exposures in place or as a complement to dietary questionnaires. It discusses critical parameters to be considered for validation of dietary biomarkers, with a particular focus on biomarker reproducibility over time. Dietary biomarkers are bio-chemical indicators of dietary exposures measured in blood, urine, and other biospecimens through various analytical methods. Two main types of dietary biomarkers with different applications can be distinguished: recovery biomarkers and concentration biomarkers. A fraction of the dietary biomarkers measured in blood or urine were found to correlate with the consumption of specific foods and have eventually been used as biomarkers of food intake. The chapter describes new opportunities to measure dietary biomarkers in alternative biospecimens such as hair, nails, and teeth, and reviews recent advances in the application of metabolomics to identify novel dietary biomarkers.
