For research published in 2022 study in the journal Food and Chemical Toxicology, scientists examined “the genotoxicity and the intracellular reactive oxygen species induction by physiologically relevant concentrations of three different TiO2 nanomaterials in Caco-2 and HT29-MTX-E12 intestinal cells, while considering the potential influence of the digestion process in the NMs’ physiochemical characteristics.” They found a “DNA-damaging effect dependent on the nanomaterial,” along with the micronucleus assay suggesting “effects on chromosomal integrity, an indicator of cancer risk, in the HT29-MTX-E12 cells, for all the tested TiO2 nanomaterials.” Researchers concluded that the results showcase “evidence of concern” regarding titanium dioxide used as a food additive.

It's also used in sunscreens as a UV filtering ingredient, helping to protect a person's skin by blocking absorption the ultraviolet light that can cause sunburn and cancer.

Prof. Matthew Wright, chair of EFSA’s working group on E171, noted: “Although the evidence for general toxic effects was not conclusive, on the basis of the new data and strengthened methods we could not rule out a concern for genotoxicity and consequently we could not establish a safe level for daily intake of the food additive.”