Scientists analyzed research that examined how titanium dioxide nanoparticles interact with the brain for a 2015 review published in Nanoscale Research Letters. The researchers wrote: “Once the TiO2 NPs are translocated into the central nervous system through [certain] pathways, they may accumulate in the brain regions. For their slow elimination rates, those NPs could remain in the brain zones for a long period, and the Ti contents would gradually increase with repeated exposure.” After reviewing dozens of studies, the scientists concluded: “Long-term or chronic exposure to TiO2 nanoparticles could potentially lead to the gradually increased Ti contents in the brain, which may eventually induce impairments on the neurons and glial cells and lead to CNS dysfunction as a consequence.”

Titanium dioxide is used a food colour (E171) and, as with all food colours, its technological function is to make food more visually appealing, to give colour to food that would otherwise be colourless, or to restore the original appearance of food. Titanium dioxide is also present in cosmetics, paints, and medicines.

Molecular weight: 412.23

In 2019, EFSA published a statement on the review of the risk related to the exposure to food additive titanium dioxide (E171) performed by the French Agency for Food, Environment and Occupational Health Safety (ANSES). In its statement, EFSA highlighted that the ANSES opinion reiterated the uncertainties and data gaps previously identified by EFSA and did not present findings that invalidated the Authority’s previous conclusions on the safety of titanium dioxide.