Comparative Impact of Bacterial and Yeast Probiotic Strains in Functional Foods: Mechanisms, Efficacy and Applications

Abstract

This review systematically examines four principal probiotic groups in the context of functional food applications: Lactobacillus, represented by L. rhamnosus GG (LGG), which enhances epithelial barrier integrity via SpaCBA pili-mediated adhesion and secreted proteins Msp1/p75 and Msp2/p40 that activate EGFR-Akt signaling to attenuate cytokine-induced apoptosis; Bifidobacterium, which mediates ecosystem-level colonic regulation through acetate-driven cross-feeding with butyrate-producing taxa and strain-specific immunomodulation including NF-κB suppression and IL-10 induction; Streptococcus thermophilus, whose high β-galactosidase activity directly hydrolyzes lactose during intestinal transit, with clinical evidence confirming viability-dependent reduction in breath-hydrogen excretion and elevation of plasma butyrate; and Saccharomyces boulardii, a eukaryotic probiotic resilient to many antibiotics that mediates rapid, transient anti-diarrheal effects through serine protease-mediated toxin degradation, mucosal IgA stimulation, and MAP kinase-dependent suppression of pro-inflammatory mediators, with clinical trials confirming significant reductions in antibiotic-associated diarrhea incidence across adult and pediatric populations. Translational trends toward postbiotics and personalized nutrition are highlighted, alongside persistent challenges including heterogeneity in strain annotation and dosing, variability in host responses, and the paucity of long-term safety data. Three priority directions are identified: systematic clinical validation of strain-specific effects and dose–response relationships; development of standardized pipelines for personalized probiotic recommendations integrating microbiome diagnostics with rigorous clinical evidence; and cautious exploration of engineered probiotic chassis and metabolite-based products with explicit assessment of technical feasibility, regulatory pathways and safety.