NATURE'S PHARMACY: PHYTOCHEMICALS AND PROBIOTICS AS THE GUARDIANS OF GUT WELLNESS AND IMMUNOLOGICAL HEALTH.

Recent studies have highlighted the significant role of dietary phytochemicals and probiotics in promoting a healthy gut microbiota and modulating immune responses. The human gut microbiota plays a pivotal role in health and disease. Diet is a key modulator of gut microbiota composition and function, which then influences immune and other systems. Phytochemicals, contribute to the health benefits associated with a plant-based diet, include polyphenols, carotenoids, glucosinolates, saponins, phytosterols and other. Adittionaly, dietary fibers, which serve as prebiotics enhance antioxidant activity, anti-inflammatory effects, cancer prevention, cardiovascular health and immune support. Understanding mechanisms of how certain compounds in diet influence human physiology is crucial for elucidating the link between diet, gut health and the development of various chronic diseases. This study aims to comprehensively investigate the intricate interplay between dietary phytochemicals and probiotics in modulating the composition and functionality of the gut microbiota, thereby investigating their pivotal role as guardians of gut wellness and immunological health within the framework of human physiology and the pathogenesis of chronic diseases. This research endeavors to provide valuable insights into the potential therapeutic strategies and ultimately prevent the onset or progression of chronic diseases associated with dysbiosis and immune dysregulation. A systematic review was conducted utilizing PubMed, Scopus and Web of Science databases. Eligible studies included dietary intervention trials, observational cohorts and cross-sectional analyses. Data extraction covered study design, demographics, interventions, microbiota analyses, immunological assays and statistical methods, while quality assessment ensured reliability. Plant-based diet abundant in fruits, vegetables, whole, non-gluten grains, nuts, seeds and legumes ensures a broad intake of these beneficial phytochemicals. Polyphenols have been shown to exhibit prebiotic-like effects and promote the growth of beneficial gut bacteria. These bacteria produce metabolites that enhance gut barrier function and reduce inflammation. Dietary fibers are fermented by gut bacteria into short-chain fatty acids (SCFAs), which have immunomodulatory properties. One SCFA, butyrate has been shown to enhance the differentiation of regulatory T cells (Tregs) and inhibit the production of pro-inflammatory cytokines, thus contributing to an anti-inflammatory immune environment. Specific probiotic strains, such as Lactobacillus rhamnosus and Bifidobacterium longum, have been demonstrated to reduce Th17 cell populations, thereby ameliorating symptoms in autoimmune diseases. Furthermore, they lower the production of pro-inflammatory cytokines and enhancing anti-inflammatory responses. On the other side, diet based on animal products has been observed to alter the balance of gut bacteria, often favoring a pro-inflammatory microbial environment. Animal-based foods, particularly those high in saturated fats, heme iron and certain proteins, can promote a pro-inflammatory gut microbiota. The metabolites produced from these compounds can damage the gut barrier, increase intestinal permeability and trigger systemic inflammation. Incorporating a diverse range of phytochemical-rich foods into the diet can provide numerous immune-boosting properties and help prevent chronic diseases. By promoting the growth of beneficial bacteria through the intake of these phytochemicals and dietary fibers, a diet rich in plant-based foods supports gut health and immune function. Understanding these mechanisms highlights the crucial role of dietary choices in maintaining gut health, reducing inflammation and preventing inflammation-related diseases. Thus, prioritizing a variety of fruits, vegetables, nuts, seeds, and whole grains can significantly contribute to overall well-being and long-term health. [ABSTRACT FROM AUTHOR]