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.

A few non-dietary studies have reported adverse effects in the gastrointestinal tract of laboratory animals given food-grade TiO₂. However, these same effects were not seen when the same or higher doses of food-grade TiO₂ were administered in the animals' diet. Dietary studies best reflect how humans are exposed to TiO₂ from food. Thus, the Food Directorate placed the most emphasis on the results of these studies in the state of the science report.