From studies deemed relevant, the experts found that titanium dioxide as a food additive is poorly absorbed by the gastrointestinal tract of mice and rats, with no adverse effects observed in short-term studies in rodents receiving titanium dioxide in their diets. No observed adverse effect levels (NOAELs) of 15,000 milligrams per kilogram of bodyweight (mg/kg BW) per day and 5,000 mg/kg BW per day—the highest doses tested—were established for mice and rats, respectively.

Most notably, a European Food Safety Authority safety assessment published in May 2021 pointed to genotoxicity concerns, as suggested by previous research. Genotoxicity is the ability of chemicals to damage genetic information such as DNA, which may lead to cancer.

Fig. 3. Cell survival measured on samples of MSSA with bare and functionalized P25TiO₂NPs after 6 h of irradiation. A: P25TiO₂NPs, B:vitaminB2@P25TiO₂NPs, C: vitaminC@P25TiO₂NPs in concentrations of 0.2 μg/mL (red) and 0.2 mg/mL (blue). p <0.05.