Kinetics of metabolite appearance and disappearance in plasma • Kinetics are metabolite specific • Influenced by host genotype • Does concentration fall to zero? • Impact of repeated exposure?
Biomarkers of food intake • follow-up feeding studies (shorter and longer) • Impact of gut microflora • Use of an external marker • Use of stable isotopes to indentify food specific biomarker • Panels or single biomarkers • Quantification (how much orange juice) • Dietary patterns: panel of markers (PHN) • Biofluids: urine and blood; most practical
metabotypes: • How to distinguish? • Numbers necessary to perform. • How many metabotypes? • Genotype: importance: need genotype metabolomic studies to put
Run-in diet: - necessary, improves the repeatability of the study - Length will depend on study in question
Concluding Remarks - Exactly what you do will depend on the study and questions to be answered