The evidence also suggests that the toxicity of TiO2 particles may be reduced when eaten as part of the diet. This is because proteins and other molecules in a person's diet can bind to the TiO2 particles. This binding alters the physical and chemical properties of the particles, which influences how they interact with cells, tissues and organs.
JECFA previously assessed titanium dioxide at its 13th meeting, at which time the expert committee assigned a “not specified” ADI for the additive due to an absence of significant absorption and a lack of toxicological effects in the available experimental animal and human studies. Since its original evaluation by JECFA, titanium dioxide has become a public point of contention, with its ban being introduced (and then subsequently withdrawn) in California legislation in 2023, a legal battle playing out in the EU over the additive’s ban and classification as a carcinogen in 2022, and the European Food Safety Authority (EFSA) calling titanium dioxide unsafe. However, supporters of titanium dioxide say that claims about its dangers are founded in unreliable studies, and some recent research has supported its safety as a food additive.