Titanium dioxide (E 171), a dangerous bleaching and dulling additive, is also absorbed through the mucous membranes of the oral cavity. This is shown by a French study (Vignard et al., 2023) published in Nanotoxicology, from which the dangerous nature of toothpastes, drugs and cosmetics containing this substance is revealed. (1)
The dangerousness of the additive E 171
Authorized in 1969 as a food additive, E 171 has been widely used in candies, chewing gum, ice cream, soft drinks, sauces, as well as in almost all dietary supplements. (2)
The scientific community has repeatedly indicated that the nanoparticles of which the titanium dioxide additive is composed, once ingested, accumulate in the liver and spleen after their absorption from the intestines, but also in the placenta, to the point of contaminating the fetus. Experiments in animal models have also shown that they can cause precancerous cells to appear in the colon.
In light of so much evidence, the use of titanium dioxide in foods and supplements has been banned in France since 2020 and throughout the European Union only in 2022. (3,4) However, this dangerous additive remains to this day authorized in cosmetics, toothpastes and drugs.
Titanium dioxide, the new study
So far, research had shown the danger of E 171 following intestinal absorption of the molecule in experiments with rodents, whose keratinized mouths do not absorb the nanoparticles.
Instead, the new study focused on absorption by the mucous membranes of the oral cavity of pigs, whose tissue is very close to human tissue histologically.
French scientists from INRAE(Institut national de recherche pour l’agriculture, l’alimentation et l’environnement) in collaboration with the LNE laboratory(National Metrology and Testing Laboratory, Paris) thus studied the risk in vivo and in vitro:
– first evaluated the passage of E 171 nanoparticles through the oral mucosa of pigs,
– Then they observed the effect of nanoparticles on human oral cells cultured in vitro.
The results of the tests
In tests, in vivo and in vitro, titanium dioxide nanoparticles have
– rapidly crossed the oral mucosa to reach the bloodstream,
– damaged the DNA of the epithelial cells that line the hollow organs (the inside of the mouth, the wall of the intestine, etc.) and act as a biological barrier against what we ingest.
Therefore, the results of the study indicate that the ban on the use of E 171 in foods and supplements is insufficient. Human exposure also occurs through all products that come into contact with the oral mucosa, so toothpastes, lipsticks and other cosmetics, including powdered if inhaled.
The wait for a drug ban
Drugs are another large area of population exposure to titanium dioxide nanoparticles. In fact, the dangerous additive is widely used as an opacifier useful for stabilizing active ingredients.
The European Commission’s decision on titanium dioxide in drugs is expected in 2025 and will take into account the evaluation report commissioned from theEuropean Medicines Agency (EMA) for April 2024.
Marta Strinati
Notes
(1) Julien Vignard, Aurelie Pettes-Duler, Eric Gaultier, Christel Cartier, Laurent Weingarten, Antje Biesemeier, Tatjana Taubitz, Philippe Pinton, Cecilia Bebeacua, Laurent Devoille, Jacques Dupuy, Elisa Boutet-Robinet, Nicolas Feltin, Isabelle P. Oswald, Fabrice H. Pierre, Bruno Lamas, Gladys Mirey & Eric Houdeau (2023) Food-grade titanium dioxide translocates across the buccal mucosa in pigs and induces genotoxicity in an in vitro model of human oral epithelium. Nanotoxicology, 17:4, 289-309, https://doi.org/10.1080/17435390.2023.2210664
(2) Marta Strinati. Titanium dioxide in foods. GIFT (Great Italian Food Trade). 25.8.17
(3) Marta Strinati. Stop titanium dioxide, interview with Francesco Cubadda, ISS expert. GIFT (Great Italian Food Trade). 8.5.21
(4) Dario Dongo. Titanium dioxide in foods and supplements, stop from 7.2.22. GIFT (Great Italian Food Trade). 21.1.22
Professional journalist since January 1995, he has worked for newspapers (Il Messaggero, Paese Sera, La Stampa) and periodicals (NumeroUno, Il Salvagente). She is the author of journalistic surveys on food, she has published the book "Reading labels to know what we eat".
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