Natural Radiance�?/FONT>
Which Sunscreens may be more foe than friend
By James Keough
With the summer sun near its zenith, the need for sunscreen would never seem greater, especially with the steady rise in the prevalence of skin cancer. According to a report in 2005 from the World Health Organization, the annual incidence for melanoma has more than doubled in the last 30 years in the US. Yet in our rush to cover up, we may actually be choosing products that could do more harm than good. The fly in the ointment, so to speak, is nanotechnology, the science of engineering materials at the sub-molecular level. It holds great promise in medicine and many other areas, but some say eager companies have rushed to use nano before they’ve thoroughly tested it—despite copious red flags about its potential for harm.
While it’s probably unfair to single out any one segment of industry, cosmetic companies have incorporated nanotechnology into their products with gusto, with anti-aging potions and sunscreens receiving the highest priority. The big push so far for nanotechnology in sunscreens stems from its ability to make two metal oxides—zinc and titanium—seemingly disappear. In bulk form (nano-speak for the way we’re used to seeing materials), these two ingredients block both UVA and UVB rays incredibly well. But they also scatter visible light rays and thus sit on the user’s skin like an unsightly white paste—a look that might be suitable for the lifeguard’s nose but is hardly en vogue for full body coverage. After all, who wants to look like Frosty the Snowman while catching some rays at the beach?
The jury’s still out
Nano-versions of these same metal oxides continue to block harmful rays, but they let visible light shine through—which means you can’t see them when you spread them on your skin. Dave Rejeski, director of The Project on Emerging Nanotechnologies (PEN) and an advocate for more research into nano’s safety issues, sees this as a valid use of the new technology. “Here’s an example where there could be some really significant benefits, because [nano sunscreens] go on easy and they’re transparent, and so if you actually can get more people to use them, it could have a significant impact.�?/FONT>
And getting people to use sunscreen more often seems laudable, especially since only about a third of Americans bother to use sunscreens regularly. But not everyone shares this enthusiastic view of nano-ized sunscreens. Jim Thomas, a researcher with the ETC Group—an organization that has called for a moratorium on the introduction of nanoproducts until more is known about their safety—worries that the consumer faces an element of risk. “You have got some pretty good evidence that says when you introduce [metal oxide particles] into living cells, you get free-radical production, which disrupts the DNA of the cell.�?/FONT>
Peter Dobson, engineering professor at the University of Oxford, confirmed this fear on ABC Radio’s The Science Show in October 2005: “The free radicals that are produced will damage the skin, damage the molecules in the skin, possibly cleave DNA in unwanted ways, and it’s best to not have that happen in your sunscreen if you can help it.�?/FONT>
Label confusion
So how do you know when a sunscreen contains nano-ized zinc or titanium? “I tell people if it’s a transparent sunscreen and it’s got either of those products, then it’s nano,�?says Thomas. Of course, zinc and titanium oxide particles have degrees of transparency, depending on their size, and to qualify as a nano, they have to measure less than 100 nanometers. So sunscreens that list “micronized�?zinc or titanium as ingredients may or may not contain nano particles of those metals. But any products that list Z-COTE or ZinClear as an ingredient clearly contain nano-ized zinc oxide, and products that list Optisol contain nano-sized titanium dioxide particles that have been coated with tiny amounts of manganese. According to Dobson, who invented Optisol, tests show this coating eliminates the formation of free radicals.
Safe or sorry?
So if the nano-ized metal oxides no longer produce free radicals, then we shouldn’t have to worry about them, right? Not necessarily. Quite a bit of research indicates that nanoparticles can find their way into the lymphatic system, breach the blood-brain barrier, and pass between the placenta and a developing fetus. Given that information, who wouldn’t think twice before rubbing a nano sunscreen on their skin? But ongoing studies in the European NANOderm project indicate that we may not need to fret much about that, at least when it comes to titanium. According to a report by project coordinator Tilman Butz, titanium dioxide particles stay blocked in the outer layer of the epidermis “and almost never penetrate to the dermis.�?/FONT>
That discovery meshes with what the cosmetic industry has continually said about nano materials in general, and they claim they have research that proves it. Unfortunately, according to Thomas, that data remains proprietary and not in the public domain—and thus, he stresses, free of independent, third-party review.
Nor must the manufacturers tell consumers when a sunscreen contains nanoparticles. “There’s no requirement of labeling, no requirement of disclosure,�?says Lisa Archer, program director for Friends of the Earth’s Campaign for Safe Cosmetics. “Until there’s some sort of regulation to clearly label whether something’s nano or not, it’s sort of a crapshoot.�?/FONT>
So what to do?
Alternatives do exist, however. Quite a few sunscreens use chemicals to absorb both UVB and UVA rays. The brand Hawaiian Tropic decided not to use metal oxides for a couple of reasons, says Dennis Lott, vice president of Technology Affairs at Tanning Research, the parent company. “The fact is there’s an argument that they’re not safe,�?he says, and that they’re not as effective at screening out UVA when they’re brought down to nano scale. Hawaiian Tropic, like a great many other sunscreens, uses avobenzone (Parsol 1789) to absorb UVA and a blend of other chemicals to absorb UVB. Companies outside the US use Mexoryl, but the FDA has yet to allow its use here.
So what to do? Steer clear of the metal oxides that go on transparently if you can, says Thomas. If you worry about the safety of the various chemicals in sunscreens and other cosmetics—as well you might since Archer says only 11 percent of them have been tested by an independent organization—check out the Skin Deep project developed by the Environmental Working Group (www.ewg.org/ reports/skindeep2/index.php). It lets you search products by category, by name, or by brand name, and gives you detailed information about each ingredient.
Sorting Out the Rays
�?Sun protection products need to screen out two types of ultraviolet rays, UVB, which produce sunburns, and UVA, which damage deeper levels of skin and cause aging and wrinkles. Both types of rays can cause skin cancer. The ability to stop sunburn earns a sunscreen a sun protection factor (SPF), which represents a multiple of the time you can spend in the sun without burning compared to the amount of time it would take you to burn without the sunscreen. Thus if you burn in 10 minutes without sunscreen, a product with an SPF of 15 would allow you to stay out for two and a half hours. The US currently has no equivalent rating for UVA protection, although the FDA promised in 1999 to establish one.
�?To receive the full benefit of a sunscreen, you must apply the amount specified on the label—generally an ounce of sunscreen for your entire body—and you must reapply it as suggested. Swimming and perspiration reduce a product’s efficiency. Note too that no sunscreen blocks out all of the sun’s rays. Nor will SPF 30 block out twice as many rays as 15. SPF 15 sunscreen blocks 93 percent of UVB rays; and SPF 30 only 4 percent more at 97 percent. Jump to SPF 50 and you gain just another 1 percent.
Courtesy of Alternative Medicine
http://www.alternativemedicine.com
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