The evidence of recent years derived from the study of the commensal microbes dwelling in the gastrointestinal tract makes it clear that the composition of this gut microbiome is influential on long term health, likely to a similar degree as exercise and diet. Further, the balance of microbial populations shifts with age in unfavorable ways. Inflammatory populations increase, contributing to the chronic inflammation of aging, while beneficial populations decrease, reducing the supply of metabolites necessary for normal tissue function.
While today's open access paper is ostensibly focused on the connections between gut microbiome and brain, the authors do discuss direct links between age-related changes in the gut microbiome and a range of conditions in the rest of the body, including cardiovascular disease and cancer. All of this lends weight to efforts to restructure the aged gut microbiome, rebalance the distribution of population numbers to youthful levels, and thus reduce its contribution to degenerative aging.
We know that rejuvenation of the gut microbiome is possible and we know that it can last for a long time following a single intervention, as fecal microbiota transplantation from a young donor to an old recipient is fairly well studied in animal models. It does restore a more youthful microbiome, and as a consequence improves health and lengthens life. It will likely be challenging to establish the use of fecal microbiota transpantation more broadly than is presently the case in human medicine, as too many unknowns are involved in a donor microbiome, but there are other options on the table that do not suffer from those issues, such as flagellin immunization or the transplantation of synthetic microbiomes with well-vetted component microbes.
There is a growing body of evidence that the interaction between various microbial organisms and the human host can affect various physical and even mental health conditions. Bidirectional communication occurs between the brain and the gut microbiome, referred to as the brain-gut-microbiome axis. During aging, changes occur to the gut microbiome due to various events and factors such as the mode of delivery at birth, exposure to medications (e.g., antibiotics), environmental exposures, diet, and host genetics. Connections to the brain-gut-microbiome axis through different systems also change during aging, leading to the development of chronic diseases.
Disruption of the gut microbiome, known as dysbiosis, can lead to a reduction in beneficial bacteria and a corresponding increase in more harmful or even pathogenic bacteria. This imbalance may predispose or contribute to the development of various health conditions and illnesses. Targeted treatment of the gut microbiome and the brain-gut-microbiome axis may assist in the overall management of these various ailments.
The purpose of this review is to describe the changes that occur in the gut microbiome throughout life, and to highlight the risk factors for microbial dysbiosis. We discuss the different health conditions experienced at various stages of life, and how dysbiosis may contribute to the clinical presentation of these diseases. Modulation of the gut microbiome and the brain-gut-microbiome axis may therefore be beneficial in the management of various ailments. This review also explores how various therapeutics may be used to target the gut microbiome. Gut biotics and microbial metabolites such as short chain fatty acids may serve as additional forms of treatment. Overall, the targeting of gut health may be an important strategy in the treatment of different medical conditions, with nutritional modulation of the brain-gut-microbiome axis also representing a novel strategy.
View the full article at FightAging
