February 16, 2012
Children Have The Highest Exposure To Titanium Dioxide Carcinogens Found in Food, Supplements and Cosmetics
Will there ever be a day when we can safely say that the consumer goods industry is not poisoning our children? New research published in ACS' journal, Environmental Science & Technology, has found that Children may be receiving the highest exposure to nanoparticles of titanium dioxide--a source of concern with regard to its potential health and environmental effects -- in a wide range of consumer goods.
The geometry of titanium dioxide (TiO2) based nanofilaments appears to play a crucial role in cytotoxicity having a strong dose-dependent effect on cell proliferation and cell death.
"There has been a great deal of research into the use of manufactured carbon nanomaterials in various products, but there are still a lot of questions about how these materials will interact with biological systems," says Dr. Nancy Monteiro-Riviere, a professor of investigative dermatology and toxicology at the Center for Chemical Toxicology Research and Pharmacokinetics at NC State. See Scientists Continue Using Nanoparticles Without Knowing How They Affect Us.
One of the complications of nanotoxicology is that the toxicity of a specific nanomaterial cannot be predicted from the toxicity of the same material in a different form. For instance, while the toxicity of inert systems such as iron oxides, gold, or silver has been investigated for nearly isotropic particles (i.e., with a low aspect ratio), the toxicity of these materials in nanofilament form cannot be predicted from their known toxicity as nanoparticles. Fully understanding the toxic mechanisms of nanoscale materials is an essential prerequisite in being able to design harmless nanomaterials whose interactions with biological cells is non-lethal.
A comprehensive study conducted by researchers at UCLA's Jonsson Comprehensive Cancer found that titanium dioxide (TiO2) nanoparticles, found in everything from cosmetics to sunscreen to paint to vitamins, caused systemic genetic damage in mice. The TiO2 nanoparticles induced single- and double-strand DNA breaks and also caused chromosomal damage as well as inflammation, all of which increase the risk for cancer.
Paul Westerhoff, Ph.D., and colleagues point out that titanium dioxide is a common additive to many consumer products where nanoparticles are absorbed by the body and then released in feces and urine, sending them to wastewater treatment plants, which cannot prevent the smallest particles from entering lakes and rivers. Only one previous study, done a decade ago, reported on titanium dioxide content in a few commercial products. To fill the knowledge gap about the sources of humans' exposures, the researchers bought and tested food, personal care products, paints and adhesives and measured how much titanium dioxide they contain.
The group found that children consume more titanium dioxide than adults do because sweets like candies, marshmallows and icing are among the products with the highest levels. The paper lists the names of the products tested and their titanium dioxide content. Westerhoff recommends that regulators shift their focus from the type of titanium dioxide used in paints and industrial processes to food-grade particles, because those are much more likely to enter the environment and pose a potential risk to humans and animals.
Once in the body, the TiO2 nanoparticles accumulate in different organs because the body has no way to eliminate them. And because they are so small, they can go everywhere in the body, even through cells, and may interfere with sub-cellular mechanisms.
In the past, these TiO2 nanoparticles have been considered non-toxic in that they do not incite a chemical reaction. Instead, it is surface interactions that the nanoparticles have within their environment that is causing the genetic damage. They wander throughout the body causing oxidative stress, which can lead to cell death.
It is a novel mechanism of toxicity, a physicochemical reaction, these particles cause in comparison to regular chemical toxins, which are the usual subjects of toxicological research.
"It could be that a certain portion of spontaneous cancers are due to this exposure," said Robert Schiestl, a professor of pathology, radiation oncology and environmental health sciences, a Jonsson Cancer Center scientist. "And some people could be more sensitive to nanoparticles exposure than others. "I believe the toxicity of these nanoparticles has not been studied enough."
April McCarthy is a community journalist playing an active role reporting and analyzing world events to advance our health and eco-friendly initiatives.