A Comprehensive Review of the Triangular Relationship Among Diet, Gut Microbiota, and Aging

Aging is a complex biological process influenced by internal and external factors, with diet and gut microbiota emerging as pivotal, interconnected modulators. This review explores their triangular relationship, emphasizing how they dynamically interact to shape health across the lifespan. Aging involves notable shifts in gut microbiota, including reduced diversity, increased pro-inflammatory taxa, and impaired production of key metabolites, like short-chain fatty acids. These changes contribute to systemic inflammation, immune-senescence, and age-related conditions, such as cognitive decline and metabolic disorders. Diet, particularly Mediterranean and plant-based patterns, plays a critical role in modulating gut microbiota by enhancing beneficial microbes and their metabolic functions. In contrast, Western-style diets rich in saturated fats and processed foods promote dysbiosis and accelerate aging. The review synthesizes evidence from human studies, animal models, and interventions to show how microbiota mediates diet-driven effects on aging. It also explores the role of specific nutrients, fiber, omega-3 fatty acids, and polyphenols in influencing microbial and host aging biology. Emerging therapies, including probiotics, prebiotics, and precision nutrition, show promise for promoting healthy aging by restoring microbial balance. However, gaps remain, including the need for long-term, age-specific studies, standardized microbiome protocols, and integrated omics approaches to support targeted longevity strategies.