By Jimmy Downs

Monday May 27, 2013 (foodconsumer.org) -- Zinc oxide is commonly used in dietary supplements as a source of zinc.  Many studies have shown this nanoparticle is toxic to cells.  A study in Biomedical and Environmental Sciences confirmed that zinc oxide is the most toxic nanoparticle, compared with titanium dioxide, silicon dioxide and aluminum oxide.

X. Q. Zhang and colleagues from Southeast University in Nanjing, China conducted the study and found all tested nanoparticles including zinc oxide, titanium dioxide, silicon dioxide and aluminum oxide caused cellular mitochondrial dysfunction, morphological modifications and apoptosis in cultured human fetal lung fibroblasts.  The toxic effect was dose dependent, meaning that high concentrations led to high toxicity.

The researchers found zinc oxide was the most toxic nanoparticles, compared with other three types.

Zinc oxide, titanium dioxide, silicon dioxide are commonly used in processed foods and dietary supplements. Zinc oxide and titanium dioxide are also commonly used in sunscreens and cosmetic products.

Although nanoparticles like zinc oxide, titanium dioxide and silicon dioxide have never been adequately tested for its safety, they are commonly used in processed foods, dietary supplements and cosmetic products.