Toxicological Impacts of Silica Nanoparticles in Food Systems

Silica nanoparticles are widely employed in the food industry as anti-caking agents, carriers for flavours and nutrients, and functional additives. Their nano-scale dimensions confer unique physicochemical properties but also raise concerns about unintended biological interactions. Oral exposure leads predominantly to passage through the gastrointestinal tract, with minimal systemic absorption; nonetheless, prolonged contact with the intestinal epithelium can alter barrier integrity and modulate local immune responses. A growing evidence base indicates that silica nanoparticles may perturb gut microbiota composition, with downstream effects on metabolic and immune homeostasis. Once ingested particles reach the gut-associated lymphoid tissues, they can interact with dendritic cells and macrophages, potentially triggering low-grade inflammatory signalling. In parallel, partial dissolution of particles yields silicic acid, which may be absorbed and eliminated via the kidneys. Chronic or high-dose exposure in animal models has occasionally produced histopathological changes in liver and spleen, suggesting dose-dependent accumulation and fibrotic processes. Overall, the toxicological impact of food-grade silica nanoparticles hinges on factors such as particle size, surface chemistry, aggregation state and interaction with food matrices, underlining the need for integrated assessments of exposure, bioavailability and immunotoxic potential.

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Toxicological Impacts of Silica Nanoparticles in Food Systems publication trend

The graph below shows the total number of articles in toxicological impacts of silica nanoparticles in food systems across all publications each year (not limited to Nature Index journals).

Technical terms

Amorphous silica nanoparticles: Non-crystalline silicon dioxide particles, typically 5–200 nm in diameter, used as food additives for anti-caking and delivery functions.

Gut microbiota: The diverse community of microorganisms residing in the gastrointestinal tract, essential for digestion, immune modulation and metabolic regulation.

Protein corona: A layer of biomolecules, primarily proteins, that adsorbs onto nanoparticle surfaces in biological fluids, altering particle identity and cellular interactions.

Kupffer cell: A specialised macrophage in the liver sinusoids responsible for clearance of particulates and modulation of hepatic immune responses.

Silicic acid: Soluble monomeric form of silicon (Si(OH)₄) released upon partial dissolution of silica nanoparticles, which may be absorbed and excreted renally.

References

1. Amorphous silica nanoparticles and the human gut microbiota: a relationship with multiple implications. Journal of Nanobiotechnology (2024).
2. Oral Excretion Kinetics of Food-Additive Silicon Dioxides and Their Effect on In Vivo Macrophage Activation. International Journal of Molecular Sciences (2024).
3. Critical review of the safety assessment of nano-structured silica additives in food. Journal of Nanobiotechnology (2016).
4. Interactions between Food Additive Silica Nanoparticles and Food Matrices. Frontiers in Microbiology (2017).
5. Sub-chronic toxicity study in rats orally exposed to nanostructured silica. Particle and Fibre Toxicology (2014).
6. The protein corona protects against size- and dose-dependent toxicity of amorphous silica nanoparticles. Beilstein Journal of Nanotechnology (2014).