Uses and benefits
Titanium dioxide has many uses in food and product development.
Due to its light-scattering properties, a small amount of titanium dioxide is added to certain foods to enhance its whiteness or opacity. Most food-grade titanium dioxide has a diameter of about 200-300 nanometers (nm). This size allows ideal light scattering, resulting in the best color. To be added to food, this additive must be 99% pure. However, this leaves room for a small amount of potential pollutants such as lead, arsenic or mercury. The most common foods containing titanium dioxide are chewing gum, candies, pastries, chocolate, coffee creamer and cake decorations.
Food preservation and packaging
Titanium dioxide is added to some food packaging to maintain the shelf life of the product. Packaging containing this additive has been shown to reduce the amount of ethylene in the fruit, thereby delaying the ripening process and extending the shelf life. In addition, this packaging has been shown to have antibacterial and photocatalytic activity, the latter reducing ultraviolet (UV) exposure.
Titanium dioxide is widely used as a color enhancer in cosmetics and over-the-counter products such as lipsticks, sunscreens, toothpastes, creams and powders. It usually comes in the form of nano-titanium dioxide, which is much smaller than the food-grade version. It is particularly useful in sunscreens because it has impressive UV resistance and helps prevent the sun's UVA and UVB rays from reaching your skin. However, because it is photosensitive-which means it can stimulate the production of free radicals-it is usually coated with silica or alumina to prevent potential cell damage without reducing its UV protection. Although cosmetics are not suitable for consumption, there are concerns that the titanium dioxide in lipstick and toothpaste may be swallowed or absorbed through the skin.
In recent decades, people's concerns about the risks of titanium dioxide consumption have increased day by day.
Group 2B carcinogen
The US Food and Drug Administration (FDA) classifies titanium dioxide as generally recognized as safe. In other words, the International Agency for Research on Cancer (IARC) has classified it as a Group 2B carcinogen-a substance that may cause cancer but lacks sufficient animal and human research. This has raised concerns about its safety in food. This classification is given because some animal studies have found that inhalation of titanium dioxide dust may cause the development of lung tumors. However, IARC concluded that foods containing this additive do not pose this risk. Therefore, today, they only recommend limiting the inhalation of titanium dioxide in industries with high dust exposure (such as the paper industry).
There are some concerns about the skin and intestinal absorption of titanium dioxide nanoparticles with a diameter of less than 100 nm.
Some small test tube studies have shown that these nanoparticles are absorbed by intestinal cells and may cause oxidative stress and cancer growth. However, other studies have found limited effects. In addition, a 2019 study pointed out that food-grade titanium dioxide is larger, not nanoparticles. Therefore, the author concluded that any titanium dioxide in food is difficult to absorb and does not pose a risk to human health. Finally, studies have shown that titanium dioxide nanoparticles do not pass through the first layer of the skin-the stratum corneum-and are not carcinogenic.
Some studies on rats have observed accumulation of titanium dioxide in the liver, spleen and kidneys. That said, most studies use higher doses than you would normally consume, so it is difficult to know whether these effects will occur in humans. A 2016 review by the European Food Safety Agency concluded that the absorption rate of titanium dioxide is extremely low, and any absorbed particles are mostly excreted through feces. However, they did find that a small amount of 0.01% is absorbed by immune cells (called intestinal-associated lymphoid tissue) and may be transported to other organs. At present, it is not clear how this will affect human health. Although most studies to date indicate that titanium dioxide consumption has no harmful effects, few long-term human studies are available. Therefore, more research is needed to better understand its role in human health.
In the United States, the content of titanium dioxide in products must not exceed 1% by weight, and because of its excellent light scattering ability, food manufacturers only need to use a small amount to achieve the desired effect. Children under the age of 10 consume the most of this additive, with an average of 0.08 mg per pound of body weight per day. In comparison, the average adult consumes about 0.05 milligrams per pound per day, although these numbers vary. This is due to children's higher intake of cakes and sweets, and their smaller body size. Due to the limited research available, there is no acceptable daily intake (ADI) for titanium dioxide. However, an in-depth review by the European Food Safety Agency found that rats that consumed 1,023 mg per pound per day had no adverse reactions. Nevertheless, more human research is needed.
Research on the side effects of titanium dioxide is limited and largely depends on the source of access:
- oral. There are no known side effects.
- eye. The compound may cause slight irritation.
- Inhale. In animal studies, inhalation of titanium dioxide dust is associated with lung cancer.
- skin. It may cause slight irritation.
Most side effects are related to inhalation of titanium dioxide dust. Therefore, there are industry standards to limit exposure.
Should you avoid it?
So far, titanium dioxide is considered safe to eat. The conclusion of most studies is that the amount consumed from food is very low and does not pose a risk to human health. However, if you still want to avoid using this additive, be sure to read food and beverage labels carefully. Chewing gum, pastries, candies, coffee creamers and cake decorations are the most common titanium dioxide foods. Keep in mind that the compounds that the manufacturer may list may have different trade names or generic names instead of "titanium dioxide", so be sure to tell yourself. Considering that titanium dioxide is mainly found in processed foods, it is easy to avoid choosing intact unprocessed foods.
In addition to cosmetics, paints and paper products, titanium dioxide is an ingredient used to whiten many foods. Foods containing titanium dioxide are usually candy, cakes, chewing gum, coffee creamer, chocolate and cake decorations. Despite some safety issues, the FDA generally believes that titanium dioxide is safe. In addition, the consumption of most people is hardly enough to cause any potential harm. If you still want to avoid the use of titanium dioxide, be sure to read the label carefully and insist on using minimally processed whole foods.