Probiotics in Human Health: Current Evidence, Mechanism of Action, and Future Perspectives

Probiotics are widely recognized for their potential to promote human health through diverse mechanisms that influence host physiology and microbial ecology. This review synthesizes current evidence on the biological functions, mechanisms of action, and therapeutic applications of probiotics. A comprehensive narrative literature review was conducted, with 143 records identified, screened, and assessed for eligibility before inclusion in the final analysis. The available evidence indicates that probiotics exert their beneficial effects through modulation of gut microbiota composition, enhancement of intestinal barrier integrity, competitive exclusion of pathogens, production of antimicrobial metabolites, and regulation of innate and adaptive immune responses. Clinical and experimental studies further suggest potential benefits in the prevention or management of antibiotic-associated diarrhea, lactose intolerance, allergic diseases, hypercholesterolemia, colorectal cancer, neurological disorders, and heavy metal toxicity. Despite promising findings, probiotic efficacy remains strain-specific and influenced by host characteristics, dosage, and treatment duration. Challenges related to strain selection, safety assessment, and standardization continue to limit broader clinical application. Overall, this narrative review provides an integrated overview of current knowledge on probiotic functionality, highlights emerging therapeutic opportunities, and identifies key research gaps that should be addressed to support evidence-based probiotic use.