Zinc-polysaccharide complexes as next-generation nutrients: A comprehensive review of preparation, structural characterization, gastrointestinal fate, and biological activities

This systematic review comprehensively examined zinc-polysaccharide complexes (ZPCs) as a significant breakthrough in traditional inorganic zinc supplementation. This review details the preparation processes through chemical synthesis and innovative microbial conversion methods. Structural characterization using multiple techniques revealed the key coordination mechanisms and the resulting physicochemical transformations. Crucially, this review discusses how the physicochemical properties dictate the zinc-binding capacity. We critically analyze the “protection-release” mechanism within the gastrointestinal tract, where polysaccharides act as pH-responsive carriers to prevent zinc precipitation and enhance mucosal permeation. Furthermore, ZPCs exhibit broad-spectrum enhanced bioactivity, including potent antioxidant, anti-inflammatory, antibacterial, immunomodulatory, intestinal barrier protective, hypoglycemic, and antitumor effects, with synergistic benefits often surpassing those of the individual components. While promising for uses in functional foods and biomedicine, the review identifies critical challenges regarding precise coordination chemistry and long-term toxicity. These insights aim to guide future research and industrial applications involved in developing these advanced zinc delivery systems.