In food, titanium dioxide is often used as an artificial color additive. Tasha Stoiber, senior scientist at the consumer health nonprofit Environmental Working Group, says titanium dioxide can generally be thought of as a paint primer – it often goes on a hard-shelled candy like Skittles before the color is added to give it a uniform shine.

The National Cancer Institute tested TiO₂ for possible carcinogenicity by the oral route of exposure by feeding rats and mice with TiO₂ (size not specified) at doses 25,000 or 50,000 ppm TiO₂ for 103 weeks. They concluded that TiO₂ was not carcinogenic.Also, the study with rats fed diets containing up to 5 % TiO₂ coated mica for 130 weeks showed no treatment-related carcinogenicity. Since the size and other TiO₂ properties were not specified or determined, we cannot generalize this conclusion and we have to take into account other possible outcomes of this scenario in different exposure conditions (other size/crystalline structure of TiO₂ etc.).