Chemical isotope labeling liquid chromatography mass spectrometry for investigating acute dietary effects of cow milk consumption on human urine metabolome

Chemical isotope labeling liquid chromatography mass spectrometry for investigating acute dietary effects of cow milk consumption on human urine metabolome

Biomarker discovery has been increasingly important in the field of metabolomics for thedetection and understanding of diseases. Of the many biofluids available for metabolomics,urine is a preferred option as it is non-invasive to collect and contains a widerange of metabolites reflective of the health status of the testing individual. However, urinealso contains many exogenous metabolites which are introduced through various sourcessuch as diet. This complicates the data interpretation when searching the metabolome fordisease-related endogenous metabolites. Since diet is difficult to control, this work aims tostudy the acute effects of diet (particularly cow milk) consumption on the human urineamine/phenol submetabolome by utilizing differential chemical isotope labeling (CIL)liquid chromatography mass spectrometry (LC-MS). LC-MS analysis of 62 urine samplescollected before and after (1 hour and 2 hours) milk intake resulted in the detection of 4985metabolites with an average of 3815 ± 206 (n = 62) detected per sample. The work aims todifferentiate the exogenous “food” metabolites from the endogenous metabolite pool andto determine any dietary effects from milk intake on the human urine metabolome.