The FDA first approved the use of titanium dioxide in food in 1966, following its 1960 removal (along with the removal of other color additives) from the agency's original Generally Recognized as Safe list. In 1977, titanium dioxide joined the list of color additives that are exempt from certification, which means titanium dioxide doesn't have to be listed on the packaging of every product it's used in, Faber noted.

The aim of this work was to examine particularly the Degussa P25 titanium dioxide nanoparticles (P25TiO₂NPs) because they are among the most employed ones in cosmetics. In fact, all kinds of titanium dioxide nanoparticles (TiO₂NPs) have gained widespread commercialization over recent decades. This white pigment (TiO₂NPs) is used in a broad range of applications, including food, personal care products (toothpaste, lotions, sunscreens, face creams), drugs, plastics, ceramics, and paints. The original source is abundant in Earth as a chemically inert amphoteric oxide, which is thermally stable, corrosion-resistant, and water-insoluble. This oxide is found in three different forms: rutile (the most stable and substantial form), brookite (rhombohedral), and anatase (tetragonal as rutile), of these, both rutile and anatase are of significant commercial importance in a wide range of applications [3]. Additionally, the nano-sized oxide exhibits interesting physical properties, one of them is the ability to act as semiconducting material under UV exposure. In fact, TiO₂NPs are the most well-known and useful photocatalytic material, because of their relatively low price and photo-stability [4]. Although, this photoactivity could also cause undesired molecular damage in biological tissues and needs to be urgently assessed, due to their worldwide use. However, not all nanosized titanium dioxide have the same behavior. In 2007, Rampaul A and Parkin I questioned: “whether the anatase/rutile crystal form of titanium dioxide with an organosilane or dimethicone coat, a common titania type identified in sunscreens, is appropriate to use in sunscreen lotions” [5]. They also suggested that with further study, other types of functionalized titanium dioxide could potentially be safer alternatives. Later, Damiani found that the anatase form of TiO₂NPs was the more photoactive one, and stated that it should be avoided for sunscreen formulations, in agreement with Barker and Branch (2008) [6,7].

Avoiding exposure

While the FDA maintains that the regulated use of titanium dioxide is safe, the European Food Safety Authority and some other experts warn of potential, serious health risks.

Of the products that include the additive in their labels, Thea Bourianne, senior manager at data consultant Label Insights, told Food Navigator USA in May 2021 that more than 11,000 products in the company's database of U.S. food and beverage products listed titanium dioxide as an ingredient. Non-chocolate candy led those numbers at 32%. Cupcakes and snack cakes made up 14%, followed by cookies at 8%, coated pretzels and trail mix at 7%, baking decorations at 6%, gum and mints at 4% and ice cream at 2%.