Excerpt: Objective biomarkers of dietary intake provide a means of assessing diet that is not dependent on study participant recall or reporting… subjective measures that can be considerable sources of bias in studies of diet and health…. Validated biomarkers exist for a number of specific nutrients… such as blood or urine concentrations for minerals and vitamins, doubly labeled water for energy, or 24-h urinary nitrogen for protein. While some nutrients may provide reasonable assessment of foods or food groups…, there is generally a lack of biomarkers for assessing whole-food or dietary pattern exposures. As considered at a recent US National Institutes of Health organized workshop, omics approaches may provide an opportunity to expand biomarker development beyond single nutrients commonly measured in blood and urine….