Probiotic Bacteria and Their Impacts on Gut Microbiota and Digestive Health: Mechanisms and Applications

Abstract

The human gut microbiota, a complex and dynamic microbial community dominated
by Bacteroidetes and Firmicutes, plays a fundamental role in maintaining host health through metabolic, protective,
and immunological functions. Probiotic bacteria, particularly Lactobacillus and Bifidobacterium species, have
emerged as critical modulators of gut homeostasis, exerting beneficial effects through multiple mechanisms,
including pathogen inhibition, immune system regulation, and enhancement of intestinal barrier integrity. Beyond
their biological significance, probiotics have found extensive applications in food biotechnology for fermentation
and preservation, as well as in clinical settings for managing gastrointestinal disorders, including antibiotic
associated diarrhea, irritable bowel syndrome, and lactose intolerance. This review synthesizes current knowledge
on the mechanistic basis of probiotic action, evaluates evidence for their health benefits, and discusses their industrial
and therapeutic applications. Key findings highlight strain-specific effects, the importance of viability and dosage,
and the need for personalized approaches due to inter-individual microbiota variability. Despite promising outcomes,
challenges remain in standardization, safety assessment, and the development of next-generation probiotics. The
present review concludes by emphasizing the potential of probiotics as versatile bio-therapeutic agents while
underscoring the necessity for further research to optimize their efficacy and expand their applications in precision
medicine.