Because of its ability to absorb UV light, it's particularly useful as an ingredient in sunscreens — while its light-scattering properties are great for applications that require white opacity and brightness, such as in paint and paper.

1345-05-7

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).

From studies deemed relevant, the experts found that titanium dioxide as a food additive is poorly absorbed by the gastrointestinal tract of mice and rats, with no adverse effects observed in short-term studies in rodents receiving titanium dioxide in their diets. No observed adverse effect levels (NOAELs) of 15,000 milligrams per kilogram of bodyweight (mg/kg BW) per day and 5,000 mg/kg BW per day—the highest doses tested—were established for mice and rats, respectively.

Well asides from making you re-think that M & M addiction (chocolate coated in Titanium Dioxide…..anyone?!)