Microbiota for Healthy Ageing: The State of Art

Human microbiota is composed by trillions of bacteria which play a crucial role in host health maintenance and disease pathogenesis and whose composition is unique in each person. Environmental conditions and dietary habits can modulate the shape of microbiota that, in turn, may contribute to mediate the effect of dietary components on health status. The development of a stable and diverse gut microbiota is essential for various host physiologic functions such as immunoregulation, pathogen prevention, energy harvest, and metabolism. Changes in microbial composition are often associated to the presence of common metabolic diseases such as obesity, type 2 diabetes, lipid disorders, metabolic syndrome. Gut microbiota composition is unique in each person and changes with age. While in adult’s microbiota is generally characterized by high biodiversity, in the elderly it becomes compositionally unstable and less diverse, a condition known as dysbiosis. Dysbiosis is often linked to deterioration of the immune system, to a state of low-grade inflammation and might be causally related to sarcopenia. Several gut bacterial species can ferment dietary fibers and produce short-chain fatty acids which exert beneficial effects on muscle mass during aging. Recently some phenolic compounds, as well as their microbic biotransformation metabolites have been shown to promote growth of specific microbial species known to be associated with an improved health status. Future studies are required to expand knowledges on implications of specific bioactive compounds and bacterial metabolites on age-related diseases. Moreover, an understanding of the role of specific micro-organisms colonizing other human body districts on host physiology should be taken in consideration.