Functional foods and dietary matrices for metabolic improvement: an integrative review of mechanisms, evidence, and future directions

Metabolic disorders, including obesity, insulin resistance, dyslipidemia, and metabolic syndrome, represent a major global health burden. This challenge underscores the need for preventive and adjunct strategies that are effective, scalable, and sustainable. Functional foods consumed within dietary matrices rather than as isolated constituents are increasingly investigated for metabolic improvement because the matrix dictates digestion kinetics, bioaccessibility, and downstream molecular signaling. This integrative review connects matrix-based functional food interventions with molecular determinants of response heterogeneity to bridge the gap between food development and clinical nutrition. Evidence is synthesized across whole foods and formulated products such as fiber-rich legumes, nuts, berries, olive oil, and fermented dairy, as well as key bioactive classes including polyphenols, peptides, and dietary fibers. Experimental and clinical studies indicate that functional foods and their matrices modulate glucose and lipid metabolism, inflammatory signaling, oxidative stress, and host-microbiome interactions. Interindividual variability is increasingly linked to genetic and epigenetic factors such as single-nucleotide polymorphisms, DNA methylation, histone modifications, and microRNA regulation. These determinants help clarify heterogeneity in outcomes, while advances in computational modeling, network pharmacology, and multi-omics integration enable network-level identification of molecular targets. Key challenges include limited trial standardization, short intervention periods, and uncertainty in bioavailability within real-world diets. Future research should prioritize individualized and matrix-aware nutritional strategies supported by robust study designs and validation across diverse populations. Ultimately, these advancements are required to strengthen causal inference and improve therapeutic outcomes in the management of metabolic diseases. Functional foods rich in bioactive compounds improve metabolic health by modulating gut microbiota, enhancing insulin sensitivity, regulating lipid and glucose metabolism, and reducing inflammation. Advances in mechanistic insight and clinical evidence support their role in metabolic improvement, while future directions highlight precision nutrition, nutrigenomics, and AI-driven strategies for personalized and sustainable metabolic health interventions. • Functional foods improve metabolism via insulin, lipid, inflammatory, and gut pathways. • Genetic and epigenetic variation contributes to heterogeneity in dietary responses. • Biomarkers can help distinguish responders from nonresponders to interventions. • Precision nutrition enables matrix-aware functional food strategies for metabolic health.