But in the U.S., titanium dioxide is found all over the grocery shelves. Candy like Skittles, Starbursts, and Jell-O, gum like Trident White peppermint gum and Mentos Freshmint Gum, cake products like Duncan Hines Creamy Vanilla Frosting, and Nabisco Chips Ahoy! cookies are just a few of the myriad food items that contain the additive.

TiO₂ comes in many different forms. However, only a few of these forms are considered food-grade (acceptable to be added to food). Many studies that raised concern about the safety of TiO₂, including the concern for genotoxicity, used forms of TiO₂ that are not considered acceptable for use in food and have different properties than food-grade TiO₂. Other studies did use food-grade TiO₂, but took steps to break the material down into smaller particles than what would normally be found in food.

Recently, Yanagisawa et al. reported that the transdermal exposure (mimicking skin-barrier dysfunction or defect) of NC/Nga mice to TiO₂ NPs (15, 50, or 100 nm), in combination with allergen, aggravated atopic dermatitis-like lesions through a T-helper type 2 (Th2) dominant immune response. The study also indicated that TiO₂ NPs can play a role in the initiation and/or progression of skin diseases, since histamine was released, even in the absence of allergen.