Previous work by INRAE (Institut national de recherche pour l’agriculture, l’alimentation et l’environnement - French National Research Institute for Agriculture, Food and the Environment) had already shown that titanium dioxide passes into the bloodstream and is accompanied by toxic effects in the intestine. One of its recent studies, conducted in collaboration with the LNA (Laboratoire National de Métrologie et d’Essais - National Laboratory of Metrology and Testing), now shows that its nanoparticles can pass directly through the mucous membranes of the mouth. This puts toothpastes in particular in the firing line.
In its press release, INRAE recalls that previous work on animal models has shown that titanium dioxide (TiO2) nanoparticles can cause the appearance of precancerous cells in the colon, among other effects in the body. Once ingested, the nanoparticles accumulate in the liver and spleen after absorption from the intestine, but also in the placenta, eventually contaminating the foetus. On the basis of the precautionary principle, the use of E171 in food has been banned in France from 2020 and in Europe from 2022. However, the researchers wondered whether there were other routes for these nanoparticles to travel.
To answer this question, scientists from INRAE, in collaboration with the LNE, studied the absorption of TiO2 by the mucous membranes of the oral cavity.
They first studied their passage in the mouth of pigs (histologically very similar to that of humans), then the effect of the nanoparticles on human oral cells in culture. Under these conditions, respectively in vivo and in vitro, the tests showed that they are indeed rapidly absorbed. Once passed, they damage the DNA of the cells by subjecting them to oxidative stress, affecting the survival of the growing cells, an effect that can affect the renewal of …
