Discovery and Validation of Banana Intake Biomarkers Using Untargeted Metabolomics in Human Intervention and Cross-sectional Studies

Background:Banana is one of the most widely consumed fruits in the world. However, information regarding its healtheffects is scarce. Biomarkers of banana intake would allow a more accurate assessment of its consumption in nutritionstudies.Objectives:Using an untargeted metabolomics approach, we aimed to identify the banana-derived metabolites presentin urine after consumption, including new candidate biomarkers of banana intake.Methods:A randomized controlled study with a crossover design was performed on 12 healthy subjects (6 men, 6women, mean±SD age: 30.0±4.9 y; mean±SD BMI: 22.5±2.3 kg/m2). Subjects underwent 2 dietary interventions:1) 250 mL control drink (Fresubin 2 kcal fiber, neutral flavor; Fresenius Kabi), and2) 240 g banana+150 mL control drink.Twenty-four-hour urine samples were collected and analyzed with ultra-performance liquid chromatography coupled to aquadrupole time-of-flight MS and 2-dimensional GC-MS. The discovered biomarkers were confirmed in a cross-sectionalstudy [KarMeN (Karlsruhe Metabolomics and Nutrition study)] in which 78 subjects (mean BMI: 22.8; mean age: 47y) were selected reflecting high intake (126–378 g/d), low intake (47.3–94.5 g/d), and nonconsumption of banana. Theconfirmed biomarkers were examined singly or in combinations, for established criteria of validation for biomarkers offood intake.Results:We identified 33 potentially bioactive banana metabolites, of which 5 metabolites, methoxyeugenolglucuronide (MEUG-GLUC), dopamine sulfate (DOP-S), salsolinol sulfate, xanthurenic acid, and 6-hydroxy-1-methyl-1,2,3,4-tetrahydro-β-carboline sulfate, were confirmed as candidate intake biomarkers. We demonstrated that thecombination of MEUG-GLUC and DOP-S performed best in predicting banana intake in high (AUCtest=0.92) and low(AUCtest=0.87) consumers. The new biomarkers met key criteria establishing their current applicability in nutrition andhealth research for assessing the occurrence of banana intake.Conclusions:Our metabolomics study in healthy men and women revealed new putative bioactive metabolites ofbanana and a combined biomarker of intake. These findings will help to better decipher the health effects of banana infuture focused studies. This study was registered at clinicaltrials.gov as NCT03581955 and with the Ethical Committeefor the Protection of Human Subjects Sud-Est 6 as CPP AU 1251, IDRCB 2016-A0013–48; the KarMeN study wasregistered with the German Clinical Trials Register (DRKS00004890). Details about the study can be obtained from https://www.drks.de.J Nutr2019;149:1701–1713