The Gut Microbiota: A Functional Hub Linking Nutrition, Immunity, and Cardiovascular Health

: Cardiovascular diseases (CVD) are still among the main causes of illness and death worldwide. In recent years, research has started to look beyond the classic risk factors and has shown growing interest in the gut microbiota, which plays an important role in cardiovascular health. This review highlights how the intestinal microbiota acts as a link between diet, the immune system, and cardiovascular disease, focusing on underlying molecular mechanisms, new potential biomarkers, and clinical relevance. Many bioactive compounds, such as trimethylamine-N-oxide (TMAO) and short-chain fatty acids (SCFAs), are produced by the gut microbiota and can influence inflammation, endothelial function, and lipid metabolism. Chronic low-grade inflammatory state (due to bacterial endotoxins entrance in bloodstream when intestinal permeability increases) contributes to the development of atherosclerosis. Multi-omics technologies have helped to understand the functional role of the microbiota better and to identify dynamic biomarkers. These include plasma TMAO levels, the Firmicutes/Bacteroidetes ratio, SCFA patterns, and the presence of microbial species with pro- or anti-inflammatory effects. Such biomarkers may be useful for risk assessment, therapeutic monitoring, and the design of personalized dietary strategies. Overall, analyzing the gut microbiota and monitoring its changes through specific biomarkers supports a preventive medicine approach based on lifestyle interventions. This strategy has strong potential to improve public health outcomes while also contributing to more sustainable healthcare systems.