The etiology of prostate cancer (PCa) remains uncertain, and the role of diet is unclear. We aimed to evaluate the role of diet, through dietary patterns, on PCa, considering tumor aggressiveness and extension. The CAPLIFE study is a population-based case-control study including a total of 428 incident PCa cases and 393 controls aged 40–80 years. Dietary information was collected through a validated food frequency questionnaire. Three dietary patterns were identified through principal component analysis: “Mediterranean,” “Western,” and “Unhealthy,” which were categorized into tertiles according to the control group cutoff points. Tumor aggressiveness and extension was determined. Logistic regression models were used to assess the association between dietary patterns and PCa. High adherence to an unhealthy dietary pattern was associated with higher odds of PCa, OR_T3vsT1 = 1.52 (95% CI 1.02–2.27), especially for cases with ISUP 1–2 and localized PCa tumors. This association was not observed with a Western or Mediterranean pattern. In conclusion, adherence to an unhealthy diet appears to be associated with higher odds of PCa, especially for cases with ISUP 1–2 and localized PCa tumors.

Background: COVID-19, caused by SARS-CoV-2, exhibits highly variable severity, from mild symptoms to respiratory failure and multiorgan dysfunction. Traditional risk factors incompletely explain this heterogeneity, highlighting the potential role of gut microbiota and host metabolomics in modulating immune responses. Methods: Thus, this study investigates how gut microbiota variations are associated with plasma metabolite profiles in COVID-19, exploring relationships between microbial and metabolic signatures and disease severity and potential therapeutic targets. In a prospective cohort of 55 patients, stool and plasma samples were analyzed using 16S rRNA sequencing and untargeted LC-HRMS metabolomics. Results: Severe COVID-19 was associated with reduced microbial diversity and enrichment of pro-inflammatory taxa, including Prevotella, Alistipes, Dialister, and Lachnoclostridium, whereas mild cases showed higher abundance of protective commensals such as Bacteroides, Faecalibacterium, and Blautia. Metabolomic profiling revealed alterations in bile acids, unsaturated fatty acids, tryptophan, and inositol phosphate pathways. Notably, linoleate levels were elevated in severe cases, showing correlations with pro-inflammatory microbes, while acylcarnitines and inositol derivatives were enriched in mild disease. Predictive functional analysis suggested that severe-associated microbes showed enhanced amino acid catabolism, oxidative glucose metabolism, and xenobiotic degradation, which may be linked to host inflammation. Conclusions: These findings highlight associations between gut microbiota composition, microbial metabolism, and circulating metabolites in COVID-19 severity. Identified microbial and metabolomic signatures may represent potential candidates to be considered biomarkers and therapeutic targets to modulate disease progression.