Unveiling Postbiotics: Advancing Definitions, Mechanisms and Their Impact on Health and Other Functional Applications

The field of microbiome science has seen rapid advancements, with probiotics, prebiotics, and postbiotics emerging as critical means for modulating gut health and systemic well-being. Among these, postbiotics represent a novel paradigm, defined as preparations of inanimate microorganisms and/or their bioactive components that confer health benefits to the host. Postbiotics offer distinct advantages over probiotics, including enhanced safety, stability, and ease of integration into functional foods, pharmaceuticals, and therapeutics. Despite their potential, the field of postbiotics is still nascent, with significant gaps in understanding their mechanisms of action, clinical efficacy, and regulatory frameworks. This review aims to provide a comprehensive synthesis of the current state of postbiotic research, focusing on their definitions, health benefits, and challenges in adoption. First, we address the historical evolution and terminological ambiguities surrounding postbiotics, highlighting the inconsistencies that complicate scientific communication and commercialization. Second, we explore their bioactive properties, mechanisms of action, and potential applications in areas such as gut health, immune modulation, metabolic regulation, and disease prevention. Third, we critically evaluate the limitations in commercializing postbiotic-based products and propose directions for future research, emphasizing the need for standardized production protocols and robust clinical trials. By integrating insights into recent advancements and identifying research gaps, this review seeks to clarify the conceptual and practical challenges associated with postbiotics and emphasize standardization as a crucial step in addressing postbiotic-related regulatory and research challenges. Through their unique combination of bioactivity, safety, and versatility, postbiotics have the potential to transform both microbiome science and public health. This work aims to inform researchers, clinicians, and industry stakeholders while laying the groundwork for the development of innovative postbiotic-based interventions. HIGHLIGHTSThis review explores the emerging field of postbiotics defined as bioactive compounds from inanimate microorganisms and their potential health benefits. Postbiotics stand out for their enhanced stability and safety compared to probiotics, offering applications in gut health, immune modulation, metabolic regulation, and disease prevention. The review addresses terminological ambiguities, mechanisms of action, and regulatory challenges while proposing directions for future research. It highlights the potential of postbiotics in areas like clinical therapies, functional foods, and sustainable production systems. By integrating recent advancements, the paper aims to guide stakeholders in harnessing the transformative potential of postbiotics in science and public health. GRAPHICAL ABSTRACT