The effects of probiotic supplementation on cerebral cognitive function: a systematic review

Alzheimer’s disease (AD) stands as a formidable challenge within the realm of neurodegenerative disorders, characterized by its inexorable progression and the profound cognitive impairments it engenders. Despite decades of research, the management of AD remains in a conundrum, with currently available treatments offering only modest symptomatic relief and none that can definitively alter the course of the disease. This investigation seeks to provide a concise overview of the influence of probiotics on the cognitive aspects of AD, drawing upon a compilation of conducted studies. The study was conducted by means of comprehensive searches in MEDLINE, Pubmed, and Google Scholar databases spanning from January 2015 to December 2020. The composition of this review adhered to the guidelines outlined by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. The evaluation of eligibility criteria was guided by the Population, Intervention, Comparator, Outcome, and Study Design (PICOS) framework, a methodology that was systematically applied to each identified research entry. Upon the implementation of the search protocol, a total of five articles that satisfied the predetermined inclusion criteria were incorporated into this review. Among these, four encompassed randomized controlled trials (RCTs), while the fifth pertained to an explorative interventional study. AD stands as a progressive neurodegenerative affliction of considerable clinical import. Through the assessment of diverse investigations, compelling evidence has emerged affirming that probiotic microorganisms, acting via the intricate gut–brain axis signaling pathway, harbor the capacity to ameliorate cognitive function in AD. The collective findings across all the studies unequivocally indicate a notable enhancement in cognitive function subsequent to the administration of probiotic supplementation (p < 0.05). While not all domains of cognitive function exhibit amelioration in response to probiotic supplementation, the consideration of incorporating probiotics within the therapeutic schema for AD warrants deliberation as a strategy to enhance cognitive performance. Despite the intricate pathophysiology of AD, probiotic supplementation exerts a discernible influence on cognitive well-being. Notably, the symbiotic interplay between the gut and the brain, elucidated through the intricate gut–brain axis, emerges as a conduit through which probiotics could potentially modulate cognitive function.