The gut microbiome has received a great deal of attention in recent years, spurred by the ability to accurately and cheaply assess the composition of the gut microbiome, specific species and their proportions, via 16S rRNA sequencing. Researchers have demonstrated that the composition of the gut microbiome shifts with age to favor species that generate chronic inflammation at the expense of species producing beneficial metabolites needed for tissue function. Researchers are also turning these tools to the oral microbiome, a distinct set of populations that might also contribute to aspects of aging in various ways.
In today's open access review paper, the authors make the point that the oral microbiome and gut microbiome are not entirely independent of one another. Microbes and metabolites can move between the two via a number of pathways. The paper restricts its context of age-related disease to frailty and sarcopenia, but many of the points made can equally be applied to other common age-related conditions. The chronic inflammation of aging in particular is disruptive to tissue structure and function throughout the body, an important mechanism driving the pathology of many age-related conditions.
The Oral-Gut Microbiota Axis as a Mediator of Frailty and Sarcopenia
Traditionally studied in isolation, the oral and gut microbiota are now being recognized as interconnected through anatomical and physiological pathways forming a dynamic "oral-gut microbiota axis". Both oral and gut microbiota undergo changes with aging, characterized by a decline in microbial diversity and a shift toward potentially harmful species. Interactions between oral and gut microbiota occur mainly through three pathways namely the enteral, the bloodstream and the fecal-oral routes. Alterations in the oral-gut microbiota axis contribute to chronic low-grade inflammation (i.e., "inflammaging") and mitochondrial dysfunction, key mechanisms underlying frailty and sarcopenia.
Microbial metabolites, such as short-chain fatty acids and modified bile acids, appear to play an emerging role in influencing microbial homeostasis and muscle metabolism. Furthermore, poor oral health associated with microbial dysbiosis may contribute to altered eating patterns that negatively impact gut microbiota eubiosis, further exacerbating muscle decline and the degree of frailty. Strategies aimed at modulating the microbiota, such as healthy dietary patterns with reduced consumption of ultra-processed foods, refined carbohydrates and alcohol, ensuring an adequate protein intake combined with physical exercise, as well as supplementation with prebiotics, probiotics, and omega-3 polyunsaturated fatty acids, are increasingly recognized as promising interventions to improve both oral and gut microbiota health, with beneficial effects on frailty and sarcopenia.
A better understanding of the oral-gut microbiota axis offers promising insights into nutritional interventions and therapeutic strategies for the age-related muscle decline, frailty, and systemic health maintenance.
View the full article at FightAging
