Urinary polyphenol signature of the Mediterranean diet is associated with lower cardiovascular disease risk: the PREDIMED trial

Background: The Mediterranean diet (MedDiet) is strongly associated with lower cardiovascular disease (CVD) risk and is particularly rich in polyphenols, bioactive compounds with potential cardioprotective effects. However, the specific phenolic compounds underlying these benefits remain unclear. The objective of this study was to develop a urinary multi-metabolite signature of phenolic compounds reflecting MedDiet adherence and to evaluate its prospective association with CVD risk. Methods: In a case–cohort nested study within the PREDIMED trial, we measured 62 phenolic metabolites in spot urine by liquid chromatography–high‐resolution mass spectrometry at baseline and after 1 year in 1180 individuals: 653 incident CVD cases (stroke, myocardial infarction, CVD death, or heart failure) and a random subcohort of 603 participants (76 overlapping cases). We applied elastic net regression to derive a urinary multi-metabolite signature prospectively associated with MedDiet adherence, measured by the validated 14-item Mediterranean Diet Adherence Screener (MEDAS). Multivariable Cox models were used to estimate hazard ratios (HRs) of CVD by levels of the multi-metabolite signature. Results: The urinary multi-metabolite signature, comprising eight phenolic compounds selected by elastic net regression, was inversely associated with CVD risk in a dose–response pattern (HR per SD = 0.80 (0.68–0.94); HR Q4 vs Q1 = 0.48 (0.30–0.78); p-trend = 0.002). The metabolites included in the signature were derived from foods typical of the MedDiet, particularly virgin olive oil, wine, nuts, fruits, and vegetables. After 1 year, MedDiet interventions significantly increased urolithin A metabolites (derived from walnuts) compared to the control group. Conclusions: We identified a urinary multi-metabolite signature of MedDiet adherence that is prospectively associated with lower CVD incidence. These findings support that polyphenols derived from the MedDiet showed inverse associations with cardiovascular outcomes. Trial registration: The study was registered with the International Standard Randomized Controlled Trial Number (ISRCTN) 35739639.