Most food-grade titanium dioxide is around 200–300 nanometers (nm) in diameter. This size allows for ideal light scattering, resulting in the best color (1Trusted Source).
A few non-dietary studies have reported adverse effects in the gastrointestinal tract of laboratory animals given food-grade TiO2. However, these same effects were not seen when the same or higher doses of food-grade TiO2 were administered in the animals' diet. Dietary studies best reflect how humans are exposed to TiO2 from food. Thus, the Food Directorate placed the most emphasis on the results of these studies in the state of the science report.
The EU expert panel did not identify an immediate health concern linked to TiO2 when used as a food additive. However, due mainly to uncertainties concerning the safety of TiO2 nanoparticles, the panel concluded that TiO2 as a food additive (E171) could no longer be considered safe.
Numerous studies have linked titanium dioxide to genotoxicity and cytotoxicity. Genotoxicity refers to a chemical’s potential to cause DNA damage, which can, in turn, lead to cancer. Cytotoxicity is a general term that refers to a characteristic of being harmful to cells.
Assessment of biocompatibility
Neutral White, 26 per cent zinc sulphide, 66 per cent barium sulphate, 5 per cent infusorial earth, 3 per cent whiting.
Skin-penetration studies
R-996: