However, most dermatologists will warn their patients not to rely on mineral makeup alone in order to be protected by the sun’s rays. This is because there can be quite a bit of variation with mineral foundation – not only with how much we apply but how much titanium dioxide the foundation contains.

In addition to the toxic effects of TiO₂ NPs, discussed in previous chapters, these NPs have been also shown to promote photosynthesis and nitrogen metabolism, resulting in the enhanced growth of spinach. It increases the absorption of light and accelerates the transfer and transformation of the light energy. It was also found that treatment with nano-sized TiO₂ significantly increased the level of antioxidant enzymes, and decreased the ROS accumulation and malonyldialdehyde content in spinach chloroplasts under visible and UV irradiation. TiO₂ NPs also increased the superoxide dismutase activity of germinating soybean, enhanced its antioxidant ability, and promoted seed germination and seedling growth.

In a 2019 study published in the journal Nanotoxicology, researchers recreated the first phase of digestion in mice and fed them titanium dioxide, then examined whether accumulation occurred in the organs. Researchers wrote: “Significant accumulation of titanium was observed in the liver and intestine of E171-fed mice; in the latter a threefold increase in the number of TiO2 particles was also measured. Titanium accumulation in the liver was associated with necroinflammatory foci containing tissue monocytes/macrophages. Three days after the last dose, increased superoxide production and inflammation were observed in the stomach and intestine. Overall, [this] indicates that the risk for human health associated with dietary exposure to E171 needs to be carefully considered.”

For a substance that is relatively unknown to the public, it’s amazing how many everyday products TiO2 can be found in. Because of its many varied properties, our skin, cities, cars, homes, food and environment are made brighter, safer, more resilient and cleaner by TiO2. With a legacy of 100 years of safe commercial use, TiO2 is only going to become more vital as our environment faces greater challenges from a growing population.