Aside from its use in paints, coatings, plastics, and paper, TiO2 is also utilized in a variety of other industrial applications. It is commonly found in cosmetics, sunscreens, and food products, where it serves as a safe and effective whitening agent. TiO2 is also used in the production of ceramics, glass, and textiles, where it enhances their appearance, durability, and resistance to fading.
Over the last several years, nanoparticles have come under scrutiny for adverse health effects. Nanoparticles are ultrafine particles between 1 to 100 nanometers in diameter. (To put this in perspective, the average human hair is around 80,000 nanometers thick.) Because of their size, which can be engineered and manipulated at the atomic or molecular level, nanoparticles exhibit unique physical, chemical, and biological properties. Titanium dioxide is one of the most commonly produced nanoparticles in the world.
In short, no, research demonstrates that E171 is safe when consumed in normal situations.
Moreover, how we're exposed to an ingredient matters significantly in terms of our health and potential toxicity.
Research shows that inhaling titanium dioxide particles in significant quantities over time can cause adverse health outcomes. Unless you work in an industrial setting, inhaling substantial amounts of titanium dioxide is highly unlikely.
Research supports that applying titanium dioxide to the skin in the form of sunscreens, makeup, and other topical products does not pose a health risk.
Overwhelmingly, research that's relevant to human exposure shows us that E171 is safe when ingested normally through foods and drugs (1,2).
Again, other research suggests that E171 could cause harm; however, those research processes did not design their studies to model how people are exposed to E171. Research that adds E171 to drinking water, utilizes direct injections, or gives research animals E171 through a feeding apparatus is not replicating typical human exposure, which occurs through food and medicine consumption.
Read more in-depth about the titanium dioxide risk at go.msu.edu/8Dp5.