Arabinogalactan as a prebiotic: physiological effects, mechanisms of action, and clinical application potential

This literature review presents current data on the role of prebiotic fibers in the regulation of gut microbiota composition, host metabolism, and immune homeostasis. Dietary fiber is not digested in the human gastrointestinal tract, but, entering the large intestine, serves as a prebiotic substrate for symbiotic microbiota. Today, there is no doubt about the important role of symbiotic microorganisms in the normal functioning of various systems of the human body. Particular emphasis is placed on short-chain fatty acids – the principal microbial fermentation products of dietary fibers – that serve as key mediators between symbiotic microbiota and host immune responses. The mechanisms by which these metabolites modulate immune cell populations, including T lymphocytes, macrophages, dendritic cells, and NK cells, are described, alongside their effects on intestinal barrier function and systemic immunity. Special focus is given to larch arabinogalactan, a well-studied natural polysaccharide with established prebiotic and immunomodulatory properties. Its structural characteristics, metabolic fate in the colon, biological activity, and clinical relevance are reviewed. The article also summarizes findings from Russian and international studies supporting the safety and efficacy of arabinogalactan and its potential applications in functional nutrition, preventive medicine, and pharmaceutical formulations.