Ultimately, most experts advise moderation, as titanium dioxide is typically found in processed foods that come with their own health risks.

Why does the exposure route matter, and what's the risk? 

Titanium dioxide is a naturally-occurring mineral found in the earth’s crust. Because of its white color, opaqueness, and ability to refract light, the ingredient is often used as a pigment, brightener, and opacifier, which is an ingredient that makes a formulation more opaque. Titanium dioxide is also a UV filter and so is an effective active ingredient in sunscreens. It’s often used in cosmetic loose and pressed powders, especially “mineral powder” cosmetics, in addition to other cosmetics, lotions, toothpaste, and soap.

“Unlike some other chemicals used in food, titanium dioxide has no nutritive, preservative, or food safety function—its use is purely cosmetic,” said CSPI principal scientist for additives and supplements, Thomas Galligan. “The prospect of titanium dioxide nanoparticles damaging DNA is concerning enough for us to recommend consumers avoid foods that have it.” 

Conclusion

There are many uses of titanium dioxide that we don't know about because they were made exempt from being on the package in 1977, said Faber, who added that nothing much has changed since – other than the FDA approving some other uses of the color additive, such as expanding the use of mica-based pearlescent pigments (prepared from titanium dioxide) as color additives in distilled spirits over recent years.

Faber argued there hasn't been enough change in these federal regulations in the decades following the FDA's approval of titanium dioxide – especially as others increasingly point to potential health consequences.