Overwhelmingly, research that’s relevant to human eating patterns shows us that E171 is safe when ingested normally through foods and drugs (1,2).

In 2019, EFSA published a statement on the review of the risk related to the exposure to food additive titanium dioxide (E171) performed by the French Agency for Food, Environment and Occupational Health Safety (ANSES). In its statement, EFSA highlighted that the ANSES opinion reiterated the uncertainties and data gaps previously identified by EFSA and did not present findings that invalidated the Authority’s previous conclusions on the safety of titanium dioxide.

The skin of an adult person is, in most places, covered with a relatively thick (∼10 μm) barrier of keratinised dead cells. One of the main questions is still whether TiO₂ NPs are able to penetrate into the deeper layers of the skin. The majority of studies suggest that TiO₂ NPs, neither uncoated nor coated (SiO₂, Al₂O₃ and SiO₂/Al₂O₃) of different crystalline structures, penetrate normal animal or human skin. However, in most of these studies the exposures were short term (up to 48 h); only few long-term or repeated exposure studies have been published. Wu et al.83 have shown that dermal application of nano-TiO₂ of different crystal structures and sizes (4–90 nm) to pig ears for 30 days did not result in penetration of NPs beyond deep epidermis. On the other hand, in the same study the authors reported dermal penetration of TiO₂ NPs with subsequent appearance of lesions in multiple organs in hairless mice, that were dermal exposed to nano-TiO₂ for 60 days. However, the relevance of this study for human exposure is not conclusive because hairless mice skin has abnormal hair follicles, and mice stratum corneum has higher lipid content than human stratum corneum, which may contribute to different penetration. Recently Sadrieh et al. performed a 4 week dermal exposure to three different TiO₂ particles (uncoated submicron-sized, uncoated nano-sized and coated nano-sized) in 5 % sunscreen formulation with minipigs. They found elevated titanium levels in epidermis, dermis and in inguinal lymph nodes, but not in precapsular and submandibular lymph nodes and in liver. With the energy dispersive X-ray spectrometry and transmission electron microscopy (TEM) analysis the authors confirmed presence of few TiO₂ particles in dermis and calculated that uncoated nano-sized TiO₂ particles observed in dermis represented only 0.00008 % of the total applied amount of TiO₂ particles. Based on the same assumptions used by the authors in their calculations it can be calculated that the total number of particles applied was 1.8 × 10¹³ /cm² and of these 1.4 x10⁷/cm² penetrated. The surface area of skin in humans is around 1.8 m²  and for sun protection the cream is applied over whole body, which would mean that 4 week usage of such cream with 5 % TiO₂ would result in penetration of totally 2.6 × 10¹⁰ particles. Although Sadrieh et al.concluded that there was no significant penetration of TiO₂ NPs through intact normal epidermis, the results are not completely confirmative.

The FDA has not updated its general guidance on safety assessments since 2007. Within that time, there has been a significant increase in research on the confluence of toxicology, nanotechnology and human health. The EU updates its guidance regularly with new science available to offer proper safety assessments, with its most recent update published in 2021.

zinc oxide content, %

In a lawsuit filed last week, a consumer alleged that Skittles were unfit for human consumption because the rainbow candy contained a known toxin – an artificial color additive called titanium dioxide.

The Evolution and Impact of Anatase Titanium Dioxide Manufacturers

Total content (as ZnS add ZnSO4)

In conclusion, titanium dioxide plays a crucial role in the rubber industry by improving the quality, performance, and appearance of rubber products. Its unique combination of properties makes it a valuable additive in rubber formulations, offering benefits such as enhanced durability, UV resistance, and processing efficiency. With its versatility and effectiveness, titanium dioxide continues to be a preferred choice for rubber manufacturers looking to create high-quality and environmentally friendly rubber products.

The disadvantage of Titanium Dioxide is that it's not cosmetically elegant, meaning it's a white, unspreadable mess. Sunscreens containing Titanium Dioxide are often hard to spread on the skin and they leave a disturbing whitish tint. The cosmetic industry is, of course, really trying to solve this problem and the best solution so far is using nanoparticles. The itsy-bitsy Nano-sized particles improve both spreadability and reduce the whitish tint a lot, but unfortunately, it also introduces new health concerns. 

In a study published in the journal Environmental Toxicology and Pharmacology in 2020, researchers examined the effects of food additives titanium dioxide and silica on the intestinal tract by grouping and feeding mice three different food-grade particles — micro-TiO2, nano-TiO2, and nano-SiO2.  With all three groups, researchers observed changes in the gut microbiota, particularly mucus-associated bacteria. Furthermore, all three groups experienced inflammatory damage to the intestine, but the nano-TiO2 displayed the most pronounced changes. The researchers wrote: “Our results suggest that the toxic effects on the intestine were due to reduced intestinal mucus barrier function and an increase in metabolite lipopolysaccharides which activated the expression of inflammatory factors downstream. In mice exposed to nano-TiO2, the intestinal PKC/TLR4/NF-κB signaling pathway was activated. These findings will raise awareness of toxicities associated with the use of food-grade TiO2 and SiO2.”

Wegman’s puts titanium dioxide in its Original Macaroni and Cheese. Campbell’s Healthy Request Chunky Chicken Corn Chowder has it, as does Food Club’s Chunky New England Clam Chowder. Marzetti uses the color agent to brighten its Cream Cheese Fruit Dip. Dairy products usually don’t need titanium dioxide to look white, but Kroger has decided to add titanium dioxide to its Fat Free Half-and-Half. And titanium dioxide isn’t only in especially white or brightly colored foods: Little Debbie adds it to Fudge Rounds and many other products. According to the Food Scores database maintained by Environmental Working Group, more than 1,800 brand-name food products have titanium dioxide on their ingredients list. That said, it can still lurk as an unspecified “artificial color,” or labels might simply say “color added.”

Below 10% substitution, 1 kg of TiO2 should be replaced by 1 kg of Lithopone 30%.  

Most food-grade titanium dioxide is around 200–300 nanometers (nm) in diameter. This size allows for ideal light scattering, resulting in the best color (1Trusted Source).

Because of the uncertainty of the impacts of nanoparticles, Made Safe exercises the precautionary principle, meaning we avoid nanoparticles until more extensive scientific testing proves their safety.

Digestive System Exposure