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Unveiling the Effects of Exposure to Titanium Dioxide Nanoparticles

​Researchers from INRA, CEA-INAC, and their partners have studied the effects of oral exposure to titanium dioxide, an additive in common foodstuffs (E171), including sweets. They provide the first evidence in animals that E171 penetrates the intestinal wall, thus entering the organism, and can create immune system disorders and induce pre-cancerous lesions in the colon.
Published on 20 January 2017
​Used in various fields (e.g., cosmetics, sunscreens, paints, building materials), titanium dioxide is a common additive in the food industry (known as E171 in Europe) for its whitening and opacifying properties. It is used in candy, chocolate products, biscuits, and chewing gums, as well as in food supplements. It is also found in some toothpaste and pharmaceutical products. Although it is composed of micro- and nanoparticles, E171 is not labeled as a "nanomaterial" since its nanoparticle content does not exceed 50% (it usually ranges between 10 and 40%).

Titanium dioxide crosses the intestinal barrier and passes into the bloodstream

The researchers orally administered E171 to rats at a dose of 10 mg per kilogram of body weight per day, which is close to human exposure. They showed, for the first time in vivo, that the titanium dioxide is absorbed through the intestine and passes into the bloodstream. The scientists found titanium dioxide particles in the animals' liver. In the spleen, which is representative of systemic immunity, exposure to E171 increases the ability of immune cells to produce pro-inflammatory cytokines when activated in vitro.

Chronic oral exposure to titanium dioxide initiates and promotes the early stages of colorectal carcinogenesis

The researchers subjected the rats to chronic oral exposure to titanium dioxide in drinking water over 100 days. In a group of rats that had previously been treated with an experimental carcinogen, exposure led to an increase in the size of the preneoplastic lesions. In a group of healthy rats exposed to the E171 additive, 4 out of 11 animals spontaneously developed preneoplastic lesions on the intestinal epithelium. The animals that had not been exposed showed no abnormalities by the end of the 100 days. These results indicate that E171 has an initiating as well as promotional effect on the early stages of colorectal carcinogenesis in animals.

This result was the subject of a press release.

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