Optical brightener with health risk
Titanium dioxide is a color pigment which has the highest covering power of all white pigments. It is chemically stable and considered non-toxic.
In medicine, it is used as a pure optical colorant with the INCI (International Nomenclature of Cosmetic Ingredients) designation CI 77891 for tablets, creams, cosmetics and in sunscreens as a mineral UV filter.
As a coloring food additive E171 , it is added, for example, to candies, chewing gum, toothpaste, mozzarella and as a white color pigment in confectionery and coatings. 90% of titanium dioxide is used in industry for the production of paints, coatings, paper and plastics.
Titanium dioxide is formed from titanium, the fourth most common metal in the world. When it reacts with oxygen, titanium dioxide (TiO2) is formed. Since pure titanium hardly occurs on earth, it has to be extracted from titanium iron ore in an energy-intensive and cost-intensive process. The manufacturing process therefore leads to the emission of greenhouse gases and is climate relevant. In Germany alone, around 550,000 metric tons of titanium dioxide are produced each year as microparticles (particles larger than 100 nm) or nanoparticles (particles smaller than 100 nm). This corresponds to a total share of 10% of the world market. Nano titanium dioxides are among the most frequently produced nanoparticles.
Uptake of titanium dioxide through the skin
In 2010, a study concluded that the uptake of nanoparticles through the skin is determined by the particle size and that this depends on the state of health of the skin. On the other hand, no statement has yet been made on the uptake of titanium dioxide particles through tattoos.
Uptake of titanium dioxide via the gastrointestinal tract
In a 2016 study by the University Hospital of Zurich, it was shown in a mouse model that titanium dioxide (nano) particles as food additive E171 below 100 nm led to an increase in further inflammation and damage to the intestinal mucosa in mice with inflammatory bowel disease. The Zurich scientists therefore recommended that patients with intestinal inflammation avoid foods containing titanium dioxide. French researchers also showed in rats in 2017 that ingestion of E171 in nanoparticle form can cause intestinal inflammation and continues to damage the immune system.
No appropriate studies are yet available on the carcinogenic potential of titanium dioxide (nano) particles after oral exposure. However, because titanium dioxide takes a long time to degrade in tissues, it has the potential to accumulate, leading to the assumption that tumors may result from accumulation. The European Chemicals Agency (ECHA) database therefore lists titanium dioxide as a possible carcinogen.
According to the German Federal Institute for Risk Assessment (BfR), it is currently not possible to assess whether the European Food Safety Authority's (EFSA) assessment of E171 can also be applied to titanium dioxide particles (CI 77891) in toothpaste used as cosmetic products and has therefore recommended further investigations.
Uptake of titanium dioxide via the lungs
The Scientific Committee on Consumer Safety (SCCS) states that based on current data and the possible classification of titanium dioxide under the CLP Regulation as a category 2 carcinogen (inhalation), the use of titanium dioxide in powder form in externals is not safe for general consumers if inhaled.
In sunscreens, titanium dioxide (nano) particles are added to prevent the whitening effect as mineral UV protection. Already defined nanoparticle forms that could lead to exposure to the lungs are not allowed here. However, a final assessment of exposure to nanoparticles and the resulting necessary amendment to the EU Cosmetics Regulation is still pending. By September 9, 2021 solid and liquid cosmetic products as well as sprays containing at least 1% titanium dioxide throughout the EU will have to be separately labeled with warnings. However, there will be no ban.
Ban on titanium dioxide in food in Europe
As of May 6, 2021, EFSA no longer considers the use of titanium dioxide as a food additive to be safe, as it is not possible to invalidate the possible genotoxic effect caused by titanium dioxide (nano) particles after reviewing more than 200 topic-relevant in vitro and in vivo studies in animals. Also, the studies do not allow a conclusion on a correlation between certain properties of titanium dioxide (nano) particles (size, texture) and the outcome of the genotoxicity studies. It is not possible to define an acceptable daily intake level. The French food safety agency ANSES also criticizes the lack of data to declare the substance as clearly safe.
As a consequence, France has therefore become the first EU member to ban titanium dioxide as a food additive from January 1, 2020. Switzerland will follow with a ban at the end of 2021. However, titanium dioxide will continue to be permitted in products such as cosmetics, sunscreens and medicines.
Titanium dioxide is an additive that is not essential and bears no relation to the potential risks. It is used exclusively to increase the visual appeal of a product and is thus merely a marketing tool.
For health and climate-related reasons, it is therefore recommended that titanium dioxide should not be added to medicines, skin care creams or groceries.
© Dr. med. Dipl. Biol. Susanne Saha 08/2021
Update from 16.10.2021:
On October 8, 2021, the EU Member States agreed to the European Commission's proposal to ban the use of titanium dioxide (E171) as an additive in food from 2022.
Update from 04.02.2022:
The European Union (EU) has adopted the ban on the use of titanium dioxide as a food additive (E171). It will come into force from February 7, 2022, and will be binding from August 7, 2022. Manufacturers will be required to replace titanium dioxide in medicines with excipients within the next three years. Before April 1st, 2024, the European Medicines Agency (EMA) will carry out a further evaluation of titanium dioxide.