Dietary (poly)phenols intake and cardiometabolic health in adolescents from Spain

[eng] The rising of cardiometabolic risk factors like obesity, higher blood pressure, and alteration in the metabolism of lipids and glucose during adolescence increase the risk of type 2 diabetes mellitus and cardiovascular diseases (CVD) and all-cause mortality in adulthood. Several observational studies and clinical trials conducted in adults have shown the role of (poly)phenols on cardiometabolic health parameters, even with the low risk of CVD mortality. In adolescents, there are few studies about (poly)phenols and cardiometabolic health, one of them is the HELENA study. Additionally, the diversity and the complexity of (poly)phenols lead to difficulties in their dietary estimation in epidemiological studies. Most of the studies evaluated dietary (poly)phenols in adolescents based on dietary tools and rarely used biomarkers in biological samples. This thesis aimed to study the role of dietary (poly)phenol, estimated by different approaches, on cardiometabolic health parameters in a cohort of 1326 adolescents aged 11 to 14 years old enrolled at baseline in the SI! Program for secondary schools in Spain. Overall, our findings suggested that among adolescents: i) dietary (poly)phenols estimated by food frequency questionnaire are related to some and greater cardiometabolic and adiposity parameters, ii) Total (poly)phenol in urine analyzed by the Folin-Ciocalteu spectrophotometric method and used as a marker of (poly)phenol intake, was inversely associated with blood pressure and lipid profile, and with better or healthier cardiovascular health., iii) A novel and accurate analytical method to identify and quantify 54 urinary phenolic metabolic (mainly microbial phenolic metabolites) even aglycones and phase II metabolites through liquid chromatography coupled to mass spectrometry was developed and some microbial phenolic metabolites like lignans (enterodiol, enterolactone, and their derivatives) and urolithins (A and B and their derivatives) were identified as candidate markers of whole grains and nuts intake, respectively, iv) some phenolic metabolites are related with better cardiometabolic health and with lower probability of presenting metabolic syndrome. The results of this thesis suggest that higher dietary (poly)phenol measure through food frequency questionaries or in urine were associated with better cardiometabolic health and its parameters like body weight/composition, blood pressure, blood glucose, and lipid profile; in adolescents from a Span