A 2023 study published in the journal Particle and Fibre Toxicology set out to examine the impact of titanium dioxide nanoparticles in mice “on the course and prognosis of ulcerative colitis,” by creating an ulcerative colitis disease model. Researchers found that the titanium dioxide nanoparticles significantly increased the severity of colitis. They also “decreased the body weight, increased the disease activity index and colonic mucosa damage index scores, shortened the colonic length, increased the inflammatory infiltration in the colon.” Researchers concluded: “Oral intake of TiO2 nanoparticles could affect the course of acute colitis in exacerbating the development of ulcerative colitis, prolonging the ulcerative colitis course and inhibiting ulcerative colitis recovery.”

A legal additive in the United States, titanium dioxide is used in everything from food to consumer goods and the U.S. Food and Drug Administration says regulated use of the product as a color additive in food is safe within certain restrictions.

Most notably, a European Food Safety Authority safety assessment published in May 2021 pointed to genotoxicity concerns, as suggested by previous research. Genotoxicity is the ability of chemicals to damage genetic information such as DNA, which may lead to cancer.

Assessment of skin penetration and biohazard in vivo

Infrared spectra were performed (from 400 to 4000 cm⁻¹) in vitamins@P25TiO₂NPs samples and the vitamins alone as controls, employing a Nicolet AVATAR 360 Fourier transform infrared spectrophotometer.

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.”

Because of its unique properties, titanium dioxide is widely used and is well known in nanoscience and nanotechnology. Titanium dioxide was one of the first materials to be used in nanotechnology products. However, the potential toxicity of titanium dioxide nanoparticles is a controversial subject. Many cosmetic companies use titanium dioxide nanoparticles. Because of its bright whiteness, it is used in products such as paints, coatings, papers, inks, toothpaste, face powder, and food colouring.