Effects of Probiotics on Gut Health and the Gut–X Axis

Gut health is a multidimensional construct involving epithelial barrier integrity, immune balance, microbial stability, and metabolic homeostasis. Disruption of these tightly coordinated elements is increasingly linked to chronic metabolic, inflammatory, and neuroimmune diseases, raising critical questions about the prevention and modulation of gut dysfunction. Mechanistically characterized probiotics can enhance gut health by strengthening epithelial defenses, shaping mucosal and systemic immune responses, and producing metabolites that engage host signaling pathways. Importantly, probiotic effects are highly strain-specific and context-dependent, highlighting the necessity of moving beyond generic probiotic concepts toward evidence-based, mechanism-driven evaluations.The broadened gut–X axis paradigm has expanded the investigative horizon of probiotic research beyond the intestine. In addition to the gut–brain axis, emerging evidence supports critical roles for probiotics in regulating gut–liver, gut–adipose, gut–muscle, gut–lung, gut–skin, and gut–reproductive tract communication. Mechanistic research has revealed that probiotics can modulate inter-organ signaling via bile acid pathways, neuroendocrine modulation, immune crosstalk, and energy metabolism, offering novel avenues for disease prevention and health optimization. However, translating these findings into effective, evidence-based strategies remains challenging, especially given the complexity of host–microbe interactions and inter-individual variability in response to probiotics.This Research Topic of Frontiers in Nutrition, entitled “Effects of Probiotics on Gut Health and the Gut–X Axis,” aims to showcase high-quality research that elucidates the mechanistic links between probiotic interventions, gut homeostasis, and inter-organ communication. We welcome original research and critical reviews addressing probiotics, next-generation probiotics, synbiotics, postbiotics, and defined microbial effector molecules, with particular emphasis on studies integrating molecular mechanisms with physiological and nutritional outcomes. Contributions employing advanced experimental models, multi-omics approaches, and translational perspectives are especially encouraged.To gather further insights into these complex interactions, we welcome articles addressing, but not limited to, the following themes:• Epithelial barrier modulation and immune regulation by probiotics• Metabolic and signaling effects of probiotics and postbiotics• Probiotic influence on gut–brain, gut–liver, and additional gut–X axes• Mechanism-based next-generation probiotics and synbiotics• Advanced experimental and omics approaches in probiotic research• Translational and clinical perspectives linking mechanisms to outcome Topic editors: Zhengyuan Zhai, Zhu ZHANG, Ming Zhang, Chun-Feng Guo Source: https://www.frontiersin.org/research-topics/77423/effects-of-probiotics-on-gut-health-and-the-gut-x-axis