Nutritional Regulation of Cardiac Metabolism and Function: Molecular and Epigenetic Mechanisms and Their Role in Cardiovascular Disease Prevention

<b>Background</b>: Cardiovascular diseases (CVDs) remain the leading cause of mortality worldwide and are strongly influenced by dietary habits. Beyond caloric intake, nutrients act as molecular signals that regulate cardiac metabolism, mitochondrial function, inflammation, and epigenetic remodeling. <b>Objectives:</b> This review aims to synthesize current evidence on how dietary patterns and specific nutritional interventions regulate cardiac metabolism and function through interconnected molecular and epigenetic mechanisms, highlighting their relevance for cardiovascular disease prevention. <b>Methods:</b> A narrative review of the literature was conducted using PubMed, Scopus, and Web of Science, focusing on studies published between 2006 and 2025. Experimental, translational, and clinical studies addressing diet-induced modulation of cardiac metabolic pathways, oxidative and inflammatory signaling, epigenetic regulation, and gut microbiota-derived metabolites were included. <b>Results:</b> The analyzed literature consistently shows that unbalanced diets rich in saturated fats and refined carbohydrates impair cardiac metabolic flexibility by disrupting key nutrient-sensing pathways, including AMP-activated protein kinase (AMPK), proliferator-activated receptor alpha (PPARα), mammalian target of rapamycin (mTOR), and sirtuin 1/peroxisome proliferator-activated receptor gamma coactivator 1-alpha (SIRT1/PGC-1α), leading to mitochondrial dysfunction, oxidative stress, chronic inflammation, and maladaptive remodeling. In contrast, cardioprotective dietary patterns, such as caloric restriction (CR), intermittent fasting (IF), and Mediterranean and plant-based diets, enhance mitochondrial efficiency, redox balance, and metabolic adaptability. These effects are mediated by coordinated activation of AMPK-SIRT1 signaling, suppression of mTOR over-activation, modulation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and nuclear factor erythroid 2-related factor 2 (Nrf2) pathways, and favorable epigenetic remodeling involving DNA methylation, histone modifications, and non-coding RNAs. Emerging evidence also highlights the central role of gut microbiota-derived metabolites, particularly short-chain fatty acids, in linking diet to epigenetic and metabolic regulation of cardiac function. <b>Conclusions:</b> Diet quality emerges as a key determinant of cardiac metabolic health, acting through integrated molecular, epigenetic, and microbiota-mediated mechanisms. Targeted nutritional strategies can induce long-lasting cardioprotective metabolic and epigenetic adaptations, supporting the concept of diet as a modifiable molecular intervention. These findings provide a mechanistic rationale for integrating personalized nutrition into cardiovascular prevention and precision cardiology, complementing standard pharmacological therapies.