At the present JECFA meeting, the committee considered additional toxicological studies relevant to the safety assessment of the chemical that investigated its toxicokinetics, acute toxicity, short-term toxicity, long-term toxicity and carcinogenicity, genotoxicity, and reproductive and developmental toxicity, as well as special studies addressing its short-term initiation/promotion potential for colon cancer. The experts acknowledged that a large number of toxicological studies have been conducted using test materials, including nanoparticles, having size distributions and physico-chemical properties not comparable to real-world uses of titanium dioxide as a food additive. The studies on non-representative materials were evaluated by JECFA, but the committee concluded that such studies are not relevant to the safety assessment of the additive.

Titanium dioxide nanoparticles have also been found in human placentae and in infant meconium, indicating its ability to be transferred from mother to fetus. 

Because of their small size, nanoparticles may have unique physical and chemical properties. These properties may cause them to interact with living systems differently than larger materials with the same chemical composition (also known as bulk materials).