Plasma metabolomic biomarkers of mixed nuts exposure inversely correlate with severity of metabolic syndrome

SCOPE: To identify the most discriminant dietary biomarkers of nuts exposure in subjects with metabolic syndrome (MetS), and investigate the potential association between exposure and the severity of the MetS diagnostic traits. METHODS AND RESULTS: We applied the untargeted LC-ESI-qToF-MS-driven metabolomic workflow to explore the changes occurring in the plasma metabolome of MetS subjects following 12-week intake of mixed nuts (30 g/d) (nuts versus control groups). Urolithin A glucuronide was the most discriminative biomarker of nut exposure, showing the highest predictive capacity [ROC AUC = 89.6% (80.8-98.4)] despite the inter-individual variation expected for a host-microbial cometabolite. Furthermore, the detection of urolithin A glucuronide in plasma showed significant inverse correlation with basal abdominal adiposity (waist circumference: r = -0.550, p<0.01; waist-hip ratio: r = -0.409, p<0.05) and impaired glycemic control (fasting insuli & HOMA-IR: r = -0.417, p