CAS registration number: 1345-05-7

≥ 5 % of standard sample

Variations of titanium dioxide are added to enhance the whiteness of paint, plastics, and paper products, though these variations differ from the food-grade ones for things we eat (1Trusted Source, 2Trusted Source).

As mentioned above, these oxide NPs are harmful in part because both anatase and rutile forms are semiconductors and produce ROS. Particularly, P25 kind has band-gap energies estimated of 3.2 and 3.0 eV, equivalent to radiation wavelengths of approximately 388 and 414 nm, respectively. Irradiation at these wavelengths or below produces a separation of charge, resulting in a hole in the valence band and a free electron in the conduction band, due to the electron movement from the valence to conduction bands. These hole–electron pairs generate ROS when they interact with H₂O or O₂ [43,44]. It was described that they can cause an increase in ROS levels after exposure to UV-visible light [45]. The NBT assay in the studied samples showed that bare P25TiO₂NPs produce a large amount of ROS, which is drastically reduced by functionalization with vitamin B2 (Fig. 5). This vitamin, also known as riboflavin, was discovered in 1872 as a yellow fluorescent pigment, [46] but its function as an essential vitamin for humans was established more than sixty years later, and its antioxidant capacity was not studied until the end of the XX century [47,48]. This antioxidant role in cells is partially explained because the glutathione reductase enzyme (GR) requires it for good functionality. This enzyme is the one in charge of the conversion of oxidized glutathione to its reduced form which acts as a powerful inner antioxidant and can quench the ROS [49,50]. The cost of this action is that the glutathione is converted to the oxidized form and needs to be recovered by the GR. Consequently, the cells need more vitamin B2. Another glutathione action is the protection against hydroperoxide. This activity is also mediated by riboflavin. Therefore, local delivery of this vitamin seems to significantly help the cells in their fight to keep the oxidative balance, once they are exposed to high levels of ROS.

Ultimately, most experts advise moderation, as titanium dioxide is typically found in processed foods that come with their own health risks.

Conclusion

It's also worth noting that even prior to the EU decision, France had already outlawed titanium dioxide in food back in January 2020.

ZnSO4 – BaS ➔ BaSO4*ZnS

Flavoring Agents

Although the evidence for general toxic effects was not conclusive, on the basis of the new data and strengthened methods we could not rule out a concern for genotoxicity and consequently we could not establish a safe level for daily intake of the food additive, commented Matthew Wright, member of the EFSA's Food Additives and Flavourings Panel in a press statement.

On absorption of UV light, photo-generated titanium dioxide particles create singlet oxygen, superoxide anions (O2-) and hydroxyl radicals (OH-) that are potent free radicals (1,2). Irradiated particles of titanium dioxide can induce oxidative damage to DNA (2) which can lead to the development of mutant cells and skin cancers (3,4,5,6) and lipid peroxidation of essential functions on the cell membrane (7).