EFSA found it could not rule out genotoxicity. Regulation (EU) 2022/63 then removed E171 from the EU list of authorised food additives. That sounds simple. The documents are less simple.
In the EFSA 2021 opinion, under "conclusions," there is a sentence with no half-measures: "it is not possible to exclude the grounds for concern regarding genotoxicity." And that sentence ended the authorisation of an additive used for decades in food.
On 6 May 2021 the European Food Safety Authority published scientific opinion 6585 on titanium dioxide. It did not prove that E171 causes cancer in humans. But it could not exclude a genotoxic concern. When a food additive has that kind of unresolved uncertainty, the precautionary principle becomes decisive. Less than a year later, Regulation (EU) 2022/63 deleted titanium dioxide from the Union list of authorised food additives. End of story? Not quite. The regulation includes transition dates and a separate unresolved question for medicines.
What the EFSA Opinion Really Says
The reference document is the opinion of the Panel on Food Additives and Flavourings published in EFSA Journal in 2021 (19(5):6585). For the first time, the assessment applied the EFSA 2018 guidance on nanotechnologies. The result was unexpected.
The additive E171 — the white pigment used in sweets, chewing gum, sauces and bakery products — contains a fraction of particles in the nanometric range, with sizes below 100 nanometres. Intestinal absorption of these particles is low, but the opinion stresses that they can accumulate in the body. If they accumulate, the safety margin becomes harder to establish.
The decisive sentence is this: "taking into account all available scientific studies and data, the Panel concluded that titanium dioxide can no longer be considered safe as a food additive". The reason was not a demonstrated human cancer effect. It was the inability to exclude genotoxic concerns. Without an established Acceptable Daily Intake, the additive was left without a safety net.
Studies on Cells and Animals
EFSA did not work in a vacuum. It weighed studies published in peer-reviewed journals, and some of them make uncomfortable reading.
In 2017, Dorier et al. exposed human intestinal Caco-2 cells to E171 for repeated periods (Nanotoxicology, DOI: 10.1080/17435390.2017.1349203). They found accumulation of reactive oxygen species, downregulation of antioxidant enzymes and oxidative DNA damage measured by Comet Assay. The effect appeared more intense with commercial E171 than with synthetic nanoparticles. The matrix of the actual additive, in short, is not the same as the pure substance in a laboratory.
Proquin et al., in 2019 in Scientific Reports (DOI: 10.1038/s41598-019-54675-0), added another piece of the puzzle: exposure to E171 altered the intestinal cell transcriptome and increased the number of colorectal tumours in a murine model. That is animal and cellular evidence, not a direct human verdict.
Finally, Bautista-Pérez et al. in 2024 (International Journal of Molecular Sciences, DOI: 10.3390/ijms25115881) fed Wistar rats with E171 for 90 days and reported multi-organ damage. Again: useful evidence for toxicological plausibility, not proof of the same effect in people at normal dietary exposure.
None of these studies is a large-scale epidemiological study in humans. So the question "does E171 cause cancer in humans?" still has no definitive answer. But the regulatory question was different: can safety as a food additive be established with enough confidence? EFSA answered no.
The Regulation That Removed It From Food
On 14 January 2022 the European Commission adopted Regulation (EU) 2022/63. Foods produced under the old rules before 7 February 2022 could continue to be placed on the market until 7 August 2022 and remain on shelves until their minimum durability date or use-by date. After that transition, E171 was no longer authorised as a food additive in the EU.
The regulation has one important unresolved area: medicines. It deleted E171 from food additive authorisations but kept a separate discussion open for medicinal products, where titanium dioxide has been used as a colouring and opacifying agent. The regulation asked the pharmaceutical sector to accelerate alternatives and foresaw a review after three years.
That is the real nuance. For food, the authorisation was withdrawn. For medicines, the replacement problem was treated separately. This is not a clean loophole in which any imported sweet with E171 is automatically legal on an Italian shelf. A food placed on the EU market still has to comply with EU food additive rules. The practical risk is different: older stock, products bought outside the EU, online cross-border sales, or labels that are not checked carefully.
How to Check If a Product Still Contains E171
If you want to check what you are buying, the ingredient list is the first document to open. Look for "titanium dioxide", "biossido di titanio" or the code "E171". It usually appears among the colourings, towards the end of the list.
Then check the context. If it is a food sold in the EU after the transition period, E171 should not appear as an authorised food additive. If it appears on a product bought online from outside the EU, or on old stock with a long shelf life, the label deserves more attention. The same caution applies to supplements and borderline products, where classification can be less obvious to a consumer.
Be careful with medicines too: the food ban does not cover them in the same way. If a tablet contains titanium dioxide, that is not automatically a food-law violation. It is a different regulatory track.
Conclusion
EFSA did not prove that E171 harms humans. It said something narrower and more important for regulation: safety as a food additive could no longer be established because genotoxicity concerns could not be ruled out. The European Union chose the precautionary principle and removed E171 from food additive authorisations.
I opened the documents so you do not have to. The question, now, is not whether one sentence on a label should panic you. It is whether the data are enough for your own threshold. The only way to know what you are buying is still to read the label — or have it read by someone with no interest in hiding anything from you.
Cited sources
- EFSA Panel on Food Additives and Flavourings, "Safety assessment of titanium dioxide (E171) as a food additive", EFSA Journal, 2021, 19(5):6585.
- Commission Regulation (EU) 2022/63 of 14 January 2022 amending Annexes II and III to Regulation (EC) No 1333/2008 as regards titanium dioxide (E171).
- Dorier M. et al., Nanotoxicology, 2017. DOI: 10.1080/17435390.2017.1349203.
- Proquin H. et al., Scientific Reports, 2019. DOI: 10.1038/s41598-019-54675-0.
- Bautista-Pérez R. et al., International Journal of Molecular Sciences, 2024. DOI: 10.3390/ijms25115881.
