The Effect of Probiotic Intervention in Ameliorating the Altered Central Nervous System Functions in Neurological Disorders: A Review

Abstract

There has been a significant rise in the occurrence of various neurological ailments worldwide. The need to investigate newer and safer intervention therapies with prophylactic and/or therapeutic effects is well understood. Probiotics have recently been shown to hold promise as an intervention option that warrants future work. Probiotic strains have shown beneficial treatment outcomes as evidenced in various animal and human studies. Although numerous articles have highlighted the role of gut microbiota and its cross-talk with human brain in modulating Central Nervous System (CNS) physiology and neurochemistry, the present review solely focuses on the ability of externally administered probiotic strains (that may or may not be part of the already existing gut microflora of an average human) in ameliorating the altered CNS functions in patients. The review aims at giving a comprehensive analysis of the studies performed on animals and humans and discusses the findings in different neurological and psychiatric disorders (Anxiety, Major Depressive disorder, bipolar disorder, schizophrenia, autism spectrum disorder, cognitive impairmentsetc). The article also highlights different mechanisms through which the probiotic bacteria operate in improving neurologic manifestations or decreasing the incidence of neurological disorders. These underlying mechanisms include both direct as well as indirect pathways involving neural, hormonal and immunological pathways. The potential of probiotics as an important dietary modification as well as a useful intervention therapy with preventive and therapeutic value for the target population holds strong. However, future evaluation into formulation designing, selecting the best probiotic strain(s) for each specific disease and safety and tolerability aspects in patients needs to be considered.