Resumen:
High dietary polyphenol intake is associated with reduced all-cause mortality and a lower incidence of cardiovascular events. However, the mechanisms involved are not fully understood. The aim of the present substudy of the PREvencion con DIetaMEDiterranea (Prevention with Mediterranean diet; PREDIMED) trial was to analyse the relationship between polyphenol intake measured by total urinary polyphenol excretion (TPE), and circulating inflammatory biomarkers and cardiovascular risk factors in elderly individuals. A substudy of 1139 high-risk participants was carried out within the PREDIMED trial. The subjects were randomly assigned to a low-fat control diet or to two Mediterranean diets, supplemented with either extravirgin olive oil or nuts. Dietary intake, anthropometric data, clinical and laboratory assessments, including inflammatory biomarkers, and urinary TPE were measured at baseline and after the one-year intervention. Participants in the highest tertile of changes in urinary TPE (T3) showed significantly lower plasma levels of inflammatory biomarkers [vascular cell adhesion molecule 1 (VCAM-1) (-9.47 ng ml-1), intercellular adhesion molecule 1 (-14.71 ng ml(-1)), interleukin 6 (-1.21 pg ml(-1)), tumour necrosis factor alpha (-7.05 pg ml(-1)) and monocyte chemotactic protein 1 (-3.36 pg ml(-1))] than those inthe lowest tertile (T1, P < 0.02; all). A significant inverse correlation existed between urinary TPE and the plasma concentration of\ VCAM-1 (r = -0.301; P < 0.001). In addition, systolic and diastolic blood pressure (BP) decreased and plasma high-density lipoprotein cholesterol increased in parallel with increasing urinary TPE (T3 vs. T1) (P < 0.005 and P = 0.004, respectively). Increases in polyphenol intake measured as urinary TPE are associated with decreased inflammatory biomarkers, suggesting a dose-dependent anti-inflammatory effect of polyphenols. In addition, high polyphenol intake improves cardiovascular risk factors-mainly BP and the lipid profile.