Orthosilicic acid in functional foods: bioavailability, metabolism, and potential in degenerative disease prevention

Orthosilicic acid (OSA), the principal bioavailable form of silicon, is emerging as a vital functional food ingredient. This review synthesizes current evidence on OSA's dietary sources, bioavailability, metabolic fate, and biological mechanisms. Given that OSA's natural bioavailability varies, stabilized delivery systems-such as choline-stabilized OSA and monomethylsilanetriol-and novel biofortification strategies are critical for optimizing its physiological benefits. Major findings indicate that OSA targets connective tissues to promote bone health by stimulating osteoblastic activity and inhibiting osteoclasts. Additionally, preclinical studies suggest that OSA has the potential to enhance collagen synthesis, support vascular repair, and exert anti-inflammatory and neuroprotective effects. Despite processing stability challenges, OSA holds significant promise. Future research should elucidate its combined roles, particularly within the proposed bone-vascular-immune axis. This review critically evaluates the bioavailability gaps and proposes the "Bone-Vascular-Immune Axis" as a novel theoretical framework for future functional food development.