Metabolic fingerprinting associated with legume consumption: discovery of food intake biomarkers by untargeted LCMS metabolomics

Consumption of legumes has been associated with beneficial effects on human health. To go in depth to the protective effects of these foods, biomarkers of intake are needed. However, only a few number of studies dealing with this topic have been already published and therefore there are not still reliable biomarkers to monitor legumes intake, particularly for pulses. The aim of this study was to identify dietary biomarkers related to an acute nutritional intervention with lentils, chickpeas and white beans, as well as to monitor their kinetics following 48h after the intake of these foods. We conducted a randomised, placebo-controlled, crossover study. Participants were healthy volunteers who ingested a single dose of the test meals (lentils, chickpeas and white beans) or control meal (pasta). Two pools of the collected urinary samples were produced: one pool with the samples of each subject after eating each food during the first 6 hours, and another pool covering the first 24 hours after each intervention. These samples were analysed by LCMS untargeted metabolomics. Results showed a high number of metabolites which urinary excretions allowed the discrimination between the different treatments, which could be potential biomarkers of legume intake. Several dipeptides and polyphenol-derived metabolites demonstrated to be the most discriminating urinary compounds following the consumption of the different types of legumes, being some of them common for all the three types of legumes, and other ones particular of one of them.