Titanium dioxide has many purposes in both food and product development.

Separately, concerns have been raised about titanium dioxide impacting one's genetic code. This can be traced to a 2009 study which found that titanium dioxide nanoparticles caused DNA damage and genetic instability in mice. A 2022 study published in Food and Chemical Toxicology also raised concerns about the DNA-damaging effects of titanium dioxide as a food additive. The study noted that results evidenced a DNA-damaging effect, and added that there may also be impacts to chromosomal integrity, an indicator of cancer risk.

Both P25TiO₂NPs (with or without vitamin B2) were not found beyond the epidermis in 99% of the analyzed TEM images (Fig. 8). This is coherent with previous findings showing that nanoparticles greater than 50 nm can not penetrate the skin, even in vivo models with movement, stretching, and friction [54]. However, in one of the zones, a few nanoparticles were observed inside a hair follicle. This could be due to the follicle exposure after the localized rupture of this physical barrier when rats were shaved in order to clean the area for cream topical administration. This finding suggests that nanoparticle-based sunscreen should not be applied on recently shaved or harmed skin, in order to avoid nanoparticle skin penetration.

Alterations in gut microbiota

Health Canada's Food Directorate recently completed a “state of the science” report on titanium dioxide (TiO₂) as a food additive. Food-grade TiO₂ is a white powder made up of small particles that has been permitted in Canada and internationally for many years as a food additive to whiten or brighten foods. Food-grade TiO₂ has long been considered safe in Canada and in other countries when eaten as part of the diet.

Key Points/Overview

Production

Following six months of phasing out the additive, titanium dioxide will be completely banned in the European Union starting August 7. France had previously banned the use of titanium dioxide in food starting in January 2020.

Titanium dioxide (TiO₂) is considered as an inert and safe material and has been used in many applications for decades. However, with the development of nanotechnologies TiO₂ nanoparticles, with numerous novel and useful properties, are increasingly manufactured and used. Therefore increased human and environmental exposure can be expected, which has put TiO₂ nanoparticles under toxicological scrutiny. Mechanistic toxicological studies show that TiO₂ nanoparticles predominantly cause adverse effects via induction of oxidative stress resulting in cell damage, genotoxicity, inflammation, immune response etc. The extent and type of damage strongly depends on physical and chemical characteristics of TiO₂ nanoparticles, which govern their bioavailability and reactivity. Based on the experimental evidence from animal inhalation studies TiO₂ nanoparticles are classified as “possible carcinogenic to humans” by the International Agency for Research on Cancer and as occupational carcinogen by the National Institute for Occupational Safety and Health. The studies on dermal exposure to TiO₂ nanoparticles, which is in humans substantial through the use of sunscreens, generally indicate negligible transdermal penetration; however data are needed on long-term exposure and potential adverse effects of photo-oxidation products. Although TiO₂ is permitted as an additive (E171) in food and pharmaceutical products we do not have reliable data on its absorption, distribution, excretion and toxicity on oral exposure. TiO₂ may also enter environment, and while it exerts low acute toxicity to aquatic organisms, upon long-term exposure it induces a range of sub-lethal effects.