Posted on 18 Oct 2016 21:44
Titanium dioxide is something we associate with paint and industrial use, so it seems scary to contemplate its use in the food we eat. Titanium, after all, is a heavy metal. However, some titanium dioxide is used in foods such as ranch dressing and other creamy salad dressings, where it serves as a whitener. Is this chemical dangerous and can it cause cancer or heavy metal poisoning?
Use of Titanium Dioxide
Titanium dioxide might be found in anything with a bright white color, including paints, paper, toothpaste, textiles, plastics, pills, tablets, sunscreen and other skin care products or cosmetics.
Titanium Dioxide in Foods
Titanium dioxide is also the most commonly used inorganic pigment in foods, and may be found in the following products:
- baked goods
- cheese and other dairy products
Titanium dioxide helps make these foods bright white and opaque but it also can help add creaminess to low-fat foods like the aforementioned salad dressings. As well, titanium dioxide is a photocatalyst which, when exposed to UV light, can be used as an antibacterial agent. Although compared to other inorganic coloring agents its use in foods is widespread, only a tiny amount of the worldwide production of over 4,000,000 ton is used for this purpose.
As per U.S. regulation, the quantity of titanium dioxide used in food may not exceed one percent by weight of the food. There are also some other restrictions. It cannot be used in some foods which have a standard of identity unless it is included in the standard. For example, although Monterey Jack cheese is sold white, without colorants to make it appear yellow, as many cheddar cheeses, titanium dioxide cannot be used to make it appear whiter, as this colorant, or any other, is not included in the standard of identity 2.
How is it Made?
Titanium dioxide is produced commercially from the mineral ilmanite, which occurs in three main crystalline forms: rutile, anatase, and brookite. Among these, only synthetic anatase is approved for food use, since it contains the fewest impurities. It is a white powder that is insoluble in water and organic solvents and is very stable, being resistant to light, pH variations, oxidation, etc.
Does Titanium Dioxide Cause Cancer or Poisoning?
You may have read that titanium dioxide may cause cancer. There is not evidence that the small amount of titanium dioxide we ingest in foods poses any such risk. It has been found to be non-genotoxic and non-carinogenic and exhibited no adverse effects in rats, mice, dogs, cats, guinea pigs, and rabbits. It is thought to be poorly absorbed in mammals. The LD50 value (Lethal Dose 50% see explanation) is greater than 25 g/kg/day for rats and 10 g for mice. If we equated this to a human, a 150-pound person would have to eat 20 to 54 ounces, or 1.25 to 3.4 pounds, of titanium dioxide per day to reach the "lethal dose" level.
The International Agency for Research on Cancer (IARC) has classified titanium dioxide dust as an IARC Group 2B carcinogen, which means it is possibly carcinogenic to humans. This was based on exposing rats to large amounts of fine titanium dioxide dust which produced an increased incidence of lung adenomas in rats of both sexes, as well as squamous-cell carcinomas in females. Although humans working around titanium dioxide dust may need to be protected from exposure, this bears little relation to titanium dioxide use in foods and products, and the 2B classification means that there is limited evidence of carcinogenicity in humans and less than sufficient evidence of carcinogenicity in experimental animals. In other words, it is possibly carcinogenic to human rather than probably carcinogenic, which would rate a Group 2A classification.