Recently, another news related to food safety rushed to the hot search of major websites-US consumers filed a lawsuit against candy maker Mars in a California court, claiming that the skittles it produced contained excessive levels of titanium dioxide (E171). High, can lead to changes in human DNA.

What exactly is titanium dioxide in Skittles? Is it safe? Let's find out.

Almost the whitest substance in the world——

Widely used as a colorant

Titanium dioxide is also called titanium dioxide. In the chemical industry, it is a star product that does its part, and it can be seen everywhere in life. Titanium dioxide, as the name suggests, is the biggest feature of white. From an academic point of view, titanium dioxide has a very high refractive index (2.614), which can reflect visible light to the greatest extent. It is almost the whitest substance in the world, and has high stability and strong adhesion. Therefore, titanium dioxide is the most ideal substance for the production of white pigments, and it is also the one with the largest market share of all pigments.

In 2021, the global titanium dioxide market will exceed USD 20 billion. Among them, the application of paint, paper and plastic pigments occupies about 80% of its market. It is no exaggeration to say that in our daily life, wherever we see bright white, there is a "figure" of titanium dioxide. In addition, inks, fibers, rubber fillers, and food and cosmetic additives applications account for 8% of its market share.

In the application of titanium dioxide, food, medicine and daily chemical additives are directly related to the human body. Especially in food applications, it is commonly found in ice cream, chocolate, candy, cakes, creamers, spreads, condiments and other products.

In cosmetics and skin care products, titanium dioxide is often used as a pigment, sunscreen and thickener. As a sunscreen ingredient, titanium dioxide reduces the incidence of sunburn. In addition, titanium dioxide is also added to most toothpastes for coloring.

Research suggests that its nanoparticles are cytotoxic—

Many countries ban food applications

For a long time, titanium dioxide was considered by scientists to be a completely non-toxic substance. Therefore, many manufacturers use titanium dioxide as a food additive. However, some recent research results suggest that titanium dioxide may not be as safe as originally thought.

Titanium dioxide is classified by the International Agency for Research on Cancer (IARC) as a Category 2B carcinogen, that is, carcinogenicity has been found in animal experiments, but the evidence is not yet sufficient, and the evidence for carcinogenicity in humans is limited. However, in recent molecular biological studies of nanoscale titanium dioxide, the safety of nanoscale titanium dioxide has been questioned. Some studies suggest that titanium dioxide nanoparticles are cytotoxic, which can cause damage to the organelles of animal cells and lead to cell apoptosis. Other studies suggest that nanoscale titanium dioxide can significantly alter the intestinal flora of experimental mice, which in turn causes colonic inflammation and changes in liver protein expression, and is more harmful to obese individuals. Of course, its carcinogenic dose is usually a large dose that the human body cannot touch on a daily basis.

In fact, titanium dioxide is chemically very stable, and its composition itself does not cause cytotoxicity. The problem is the particle size of nano-sized titanium dioxide. Very small particles of many substances can have a similar effect.

According to the European Food Safety Authority (EFSA), the proportion of nano-sized titanium dioxide in titanium dioxide may be as high as 50%, and existing data and evaluation methods cannot rule out the concern that nanoparticles may cause genotoxicity, and thus cannot determine the safety of daily intake of food additives Level. In 2019, the French Food Safety Authority took the lead in issuing a ban on the production and import of food containing titanium dioxide in France. Earlier this year, the European Union also issued a ban on the use of titanium dioxide as a food additive, which came into effect on August 7 of the same year. Other countries and regions are following suit. At present, the Gulf countries, SADC countries and Switzerland have also followed the ban.

In my country, the "National Food Safety Standard - Standard for the Use of Food Additives" (GB2760-2014) stipulates that titanium dioxide can be used as a colorant, and the limited amount varies according to different types of food. For example, in candy, it is allowed to be used in moderation according to production needs; and in chocolate, it is specified as 2 g/kg.

No single substance has yet been found to be able to replace -

The transition period for the replacement of drugs and cosmetics is long

Following the EFSA ban on titanium dioxide, the European Medicines Agency (EMA) has also issued technical guidelines for the replacement or removal of titanium dioxide. But the EMA admits that no single substance has so far been found to provide the combination of properties unique to titanium dioxide. Possible substitutes include calcium carbonate, talc, and starch, but these have drawbacks. The EMA said that if titanium dioxide cannot be added to medicines, it will almost cause a large shortage of medicines, and cause these medicines to be discontinued or even withdrawn from the EU or European Economic Area market. Thus, unlike the food industry, titanium dioxide is temporarily kept on the list of permitted additives to allow its use as a colorant in pharmaceutical products in order to safeguard the supply of medicines. The EMA quality working group said there is currently no mechanism for regulators to prioritize products to be reformulated, and the transition period to replace titanium dioxide would take 10 years or even longer. Of course, Europe is accelerating the replacement process with the release of technical guidelines.

Not only that, titanium dioxide plays an important role in cosmetic formulation design and is currently the safest sunscreen additive. If titanium dioxide cannot be used, almost all types of sunscreen products need to be redesigned. However, in order to reduce the risk of skin cancer caused by long-term ultraviolet rays, national agencies led by the US Food and Drug Administration (FDA) still recommend sunscreen products containing titanium dioxide. The FDA believes that titanium dioxide particles, as a physical sunscreen, generally stay on the surface of the skin and will not be absorbed by the skin, so they have less impact on the human body. In fact, the only ingredients recommended by the FDA for sunscreens are titanium dioxide and zinc oxide. Currently, the FDA's maximum concentration limit for titanium dioxide in sunscreen cosmetics is 25%. At present, the EU continues to allow the use of titanium dioxide in sunscreen products, but stipulates that cosmetics must clearly label titanium dioxide particles smaller than 100 nanometers to ensure consumers have the right to know and choose.