The global population of elderly aged > 60 is growing faster than all other younger age groups. Although it is interpreted by some as the unstoppable success story of global life expectancy, in reality, extended lifespan has also become a cause for concern especially with regard to the inevitable increased burden of late-life diseases, worsened quality of life and increased incidence of dementia and neurocognitive disorders amongst others. It is now known that gut microbiota homeostasis is crucial for healthy aging. The composition of gut microbiota changes over time and aging is characterised by a frail gut. Recent growing body of evidence on the Gut-Brain Axis has further linked potential factors of neurodegeneration to altered composition of gut microbiota. The fact that there are many neurons connecting the central nervous system (CNS) to the enteric nervous system (ENS) of the GIT (also known as the second brain) raises the possibility that changes in the microbiota may have diagnostic value, and thereby serve as a basis to design therapeutic approaches against neurological and neurodegenerative disorders.