Discovery of Intake Biomarkers of Lentils, Chickpeas and White Beans by Untargeted LC‐MS Metabolomics in Serum and Urine

SCOPE: To identify reliable biomarkers of food intake (BFIs) of pulses. METHODS AND RESULTS: A randomized crossover postprandial intervention study was conducted on 11 volunteers who consumed lentils, chickpeas and white beans. Urine and serum samples were collected at distinct postprandial time points up to 48 h, and analyzed by LC-HR-MS untargeted metabolomics. Hypaphorine, trigonelline, several small peptides and polyphenol-derived metabolites proved to be the most discriminating urinary metabolites. Two arginine-related compounds, dopamine sulfate and epicatechin metabolites, with their microbial derivatives, were identified only after intake of lentils, whereas protocatechuic acid was identified only after consumption of chickpeas. Urinary hydroxyjasmonic and hydroxydihydrojasmonic acids, as well as serum pipecolic acid and methylcysteine, were found after white bean consumption. Most of the metabolites identified in the postprandial study were replicated as discriminants in 24 h urine samples, demonstrating that in this case the use of a single, noninvasive sample was suitable for revealing the consumption of pulses. CONCLUSIONS: The results of the present untargeted metabolomics work revealed a broad list of metabolites that are candidates for use as biomarkers of pulse intake. Further studies are needed to validate these BFIs and to find the best combinations of them to boost their specificity.