Rocío Magali Gutiérrez-Romero

Extra virgin olive oil (EVOO) is a hallmark of the Mediterranean diet and an important dietary source of bioactive phenolic compounds, including hydroxytyrosol and tyrosol derivatives, which have been investigated in relation to cardiometabolic health. However, the potential metabolic effects of phenolic-rich EVOO in young healthy adults remain poorly characterized. In this randomized crossover trial, 28 healthy adults (29.0 ± 3.4 years) consumed either phenolic-rich EVOO or regular olive oil (OO) (0.7 g/kg/day) for 4 weeks. The cardiometabolic outcomes reported here were secondary endpoints of the trial. Anthropometric measurements, cardiometabolic biomarkers, and urinary phenolic metabolites were assessed at baseline and after each intervention period; selected phenolic metabolites were quantified in 24-h urine using targeted LC–HRMS. Treatment effects were evaluated using mixed-effects models. Compared with OO, EVOO markedly increased urinary hydroxytyrosol-glucuronide (GMR = 9.9; 95% CI: 2.0, 49.0; p = 0.005), together with other hydroxytyrosol- and tyrosol-derived metabolites, providing objective evidence of greater phenolic exposure during the EVOO intervention. Exploratory between-intervention differences favored EVOO for waist circumference (β = −2.21 cm; 95% CI: −3.37, −1.05), waist-related indices, and HbA1c (β = −0.13%; 95% CI: −0.25, −0.01). In exploratory analyses, increases in urinary hydroxytyrosol-glucuronide during EVOO intake were inversely correlated with changes in HbA1c (Spearman’s rho = −0.49, p = 0.011) and WHR (rho = −0.38, p = 0.048). Post hoc sensitivity analyses showed greater stability for the waist-circumference estimate than for HbA1c. Overall, phenolic-rich ‘Corbella’ EVOO substantially increased urinary phenolic metabolite exposure, whereas the observed cardiometabolic differences should be considered exploratory and hypothesis-generating and require confirmation in larger trials specifically powered for these outcomes.

Tomatoes are the major dietary source of lycopene, a carotenoid that crosses the blood–brain barrier and exerts antioxidant and anti-inflammatory effects. However, the impact of tomato consumption on cognitive function in healthy adults remains unclear. This study assessed the effects of concentrated tomato paste on cognitive performance and explored potential mechanisms, including brain-derived neurotrophic factor (BDNF) and functional brain connectivity. A randomized, two-period crossover trial (ClinicalTrials.gov: NCT05891977) was conducted in 47 healthy adults aged 40–55 years assigned to two 3-month interventions separated by a 1-month washout: (a) daily consumption of concentrated tomato paste (0.5 g/kg body weight) and (b) a lycopene-restricted control diet. Cognitive performance was evaluated using validated neuropsychological tests (d2-R, Face-Name Associative Memory Exam, Modified Wisconsin Card Sorting Test), alongside plasma lycopene and BDNF, and resting-state functional magnetic resonance imaging (fMRI). Forty-two participants completed the study. Tomato intake improved selective attention (concentration performance: +7.2 points; processing speed: +8.3 points) and associative memory (face-name matching: +0.8 points). Plasma BDNF showed a borderline increase with tomato intake (mean difference 15.2 ng/mL). Resting-state fMRI revealed changes in brain networks, including reduced connectivity in frontoparietal and auditory networks, contrasting with reductions in the dorsal attention network during the control period. These findings provide evidence that tomato consumption may support cognitive function and modulate brain connectivity in healthy middle-aged adults.

In this pilot substudy, EVOO intake was associated with higher urinary HT-glucuronide and occipital resting-state connectivity, with an intervention-dependent metabolite-connectivity interaction.

Walnuts (Juglans regia L.) are attracting increasing interest from consumers, industries, and the healthcare community due to their high content of bioactive compounds, including (poly)phenols, carotenoids, tocopherols, and omega-3 fatty acids. Despite the continued growth in global walnut production, the effective valorisation of walnut processing by-products remains a challenge. While most research has focused on the edible kernel, emerging evidence suggests that underutilised walnut fractions may also represent valuable sources of compounds with antioxidant and anti-inflammatory properties. This study aimed to characterise the bioactive compound profiles of green walnuts, defective walnuts, and walnut shells in comparison with commercial whole walnuts and kernels. Samples collected from an orchard located in Huesca (Spain) were homogenized and analysed in triplicate. Proximate composition was determined using official methods, the fatty acid profile was determined by GC-FID, the phenolic profile by UHPLC-ESI-MS/MS, and carotenoids and tocopherols by UPLC-DAD. Green walnuts contained exceptionally high concentrations of carotenoids, especially β-carotene (629.7 ± 39.4 mg kg⁻¹). Walnut shells were the richest source of phenolic compounds, notably ellagic acid (713.3 ± 7.6 mg kg⁻¹) and catechin (71.9 ± 1.2 mg kg⁻¹). Tocopherols were mainly concentrated in the kernel, dominated by γ-tocopherol (226.9 ± 8.1 mg kg⁻¹), while defective walnuts showed a compositional profile similar to commercial walnuts. This comparative analysis highlights the significant potential of walnut processing by-products as sources of nutritionally relevant bioactive compounds. These findings support their valorisation as functional ingredients for agro-food and cosmetic applications within a circular economy framework.