Gut Brain Axis and Neurodegenerative Diseases. Nutritional Interventions Targeting Gut Microbiome: A Systematic Review

The Microbiota-gut–brain axis (GBA) comprises a bidirectional communication between the gut and brain. Many neurodegenerative disorders (NDDs), such as Alzheimer’s disease (AD), Parkinson’s disease (PD), and Multiple sclerosis (MS) are characterized by a disfunction of the GBA, indicating a possible implication role in disease patho-genesis. This systematic review was performed according to PRISMA guidelines, mainly using the key words gut–brain axis, gut microbiota, gut dysbiosis, neurodegenerative disorders, prebiotics and probiotics. The most recent scientific articles were searched from the Pubmed, Scopus, and Google Scholar databases. The main components and communication pathways of the GBA were discussed in this study and the aim was to investigate if therapeutic approaches, through dietary intervention targeting the gut microbiota, can ameliorate NDDs. The gut microbiota is a significant constituent of the GBA, and an unbalanced microbiota, known as dysbiosis, has been associated with GBA perturbation and neurodegeneration. In most of the studies discussed, manipulation of microbial composition through nutritional intervention, probiotic and prebiotic supplementation, has shown encouraging outcomes. More research is essential for the full understanding of the mechanisms studied.