In addition to pigments and sunscreens, titanium dioxide is also used in the production of paper, food products, and pharmaceuticals. In the paper industry, titanium dioxide is added to paper coatings to improve brightness, smoothness, and printability. In the food industry, titanium dioxide is used as a whitening agent in products such as candies, chewing gum, and icing. In the pharmaceutical industry, titanium dioxide is used as a coloring agent in tablets and capsules.

Specification:

In a 2017 study published in Scientific Reports, researchers exposed rats to human-relevant levels of E171 to examine the effects of intestinal inflammation and carcinogenesis. They saw that “a 100-day E171 treatment promoted colon microinflammation and initiated preneoplastic lesions while also fostering the growth of aberrant crypt foci in a chemically induced carcinogenesis model.” They continued: “Stimulation of immune cells isolated from Peyer’s Patches [which are clusters of lymphoid follicles found in the intestine] showed a decrease in Thelper (Th)-1 IFN-γ secretion, while splenic Th1/Th17 inflammatory responses sharply increased,” researchers wrote. “A 100-day titanium dioxide treatment promoted colon microinflammation and initiated preneoplastic lesions.” The scientists concluded: “These data should be considered for risk assessments of the susceptibility to Th17-driven autoimmune diseases and to colorectal cancer in humans exposed to TiO2 from dietary sources.”

Relative to a lot of other things that people should be concerned about, titanium dioxide in my mind, is really low on the list. I would be more worried about some substitutes that people are using for titanium dioxide that don't have decades of research associated with it, said Westerhoff.