Stop titanium dioxide, interview with Francesco Cubadda, ISS expert

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After years of institutional warnings and silences, on 6.5.21 EFSA finally put titanium dioxide on the index. The final shove against the genotoxic dye came thanks to a combination of three factors: a review of a purely recent assessment-the one EFSA had conducted in 2016 highlighting knowledge gaps-the adoption of nanospecific risk guidance, and the availability of a large body of scientific data.

‘This is the first time that, the guidance of EFSA’s Scientific Committee on Nanotechnology is applied to the safety assessment of food additives and experts who assess the risk related to nanoparticles are also involved. A forward-looking choice of EFSA’, comments Francesco Cubadda, coordinator of the working group on the safety assessment of nanotechnology in the food sector at the Istituto Superiore di Sanità (ISS) and an expert involved in the titanium dioxide assessment, who analyzes the salient aspects of the case.

Dr. Cubadda, the scientific community has been highlighting the toxicity of titanium dioxide for many years. At first glance, it seems that the European Commission has given the food industry time to change additive…

Titanium dioxide has ended up at the center of an international controversy. As is always the case in these cases, each side in the game has its own point of view. Titanium dioxide manufacturers for example have always maintained that the material is not harmful, even in the eyes of the food industry. This is not surprising. In fact, EFSA is a scientific body that conducts risk assessments based on mandates. This reassessment took place when the European Commission mandated EFSA to carry it out. The Executive could no longer stall because France had banned titanium dioxide with a national standard and the European Parliament had taken sides. There were scientific opinions from member countries, France and the Netherlands especially, pointing out major risks.

What role did the ISS play?

ISS has been at the forefront of producing scientific evidence. The working group I coordinate played a role in producing toxicity and exposure data on titanium dioxide, which were also used in this latest assessment. ISS is also one of six centers recognized by the European Commission as expert centers that have developed new analytical methods for nanomaterials in food, most recently on titanium dioxide itself.

Dr. Cubadda, can you summarize the toxicity of titanium dioxide?

Titanium dioxide is a material composed of insoluble particles, which are poorly absorbed by the intestines, but eliminated very slowly. They accumulate in different organs, liver and spleen especially. It has ability to produce effects on the central nervous system, that is, to act as a neurotoxicant. It also has inflammatory effects, on the immune system, and induces changes in the colon and rectum that can evolve, over time, into cancer. The decisive aspect in the evaluation, however, was genotoxicity.

Genotoxicity, the risk of DNA damage, had not emerged in the literature so far?

Thousands of jobs were used as a starting point in the evaluation. After careful selection, a few dozen with quality data were identified. And several of these papers showed non-negligible effects, studies conducted with even particles of similar size to those in the food additive showing genotoxic effects without the possibility of identifying a threshold for them. Obviously, a food additive intended to be ingested daily cannot be genotoxic. In this particular case, it was determined to be unsafe for food use, including dietary supplements.

Now what will happen?

Now the European Commission will propose that member states remove it from foods. The question of other uses that result in oral exposure, such as use in pharmaceuticals, remains open. Most white medication tablets contain titanium dioxide. Use in toothpastes can also result in ingestion of the substance, although exposure levels are lower.

Titanium dioxide is also widely used in cosmetics, especially in sunscreens. Are there any risks?

In sunscreens, titanium dioxide is entirely nanomaterial. The purpose is to have a transparent layer, so the particle size is much smaller compared to the food additive. In this case, however, there is no risk because the skin barrier is very efficient in preventing systemic exposure. The only caution is to avoid contact with injured skin, altered by injury or burns, as well as lips.

Are you satisfied with how the titanium dioxide assessment ended?

As a researcher, I appreciate the robustness of the evaluation framework put in place by EFSA. Then, this assessment resolves controversies that had generated fears among European citizens, attracted media attention, and fueled political tensions. It was necessary to put together all the evidence that had emerged over the years and come to a conclusion. There is a win-win for everyone, primarily for citizens who see their health protected.

Marta Strinati

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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".