Fecal Bacteria as an Addition to the Lineup of Objective Dietary Biomarkers

Objective biomarkers of dietary intake provide a means of assessing diet that is not dependent on study participant recall or reporting (1, 2), subjective measures that can be considerable sources of bias in studies of diet and health (3, 4). Validated biomarkers exist for a number of specific nutrients (1, 5), such as blood or urine concentrations for minerals and vitamins, doubly labeled water for energy, or 24-h urinary nitrogen for protein.