Reprinted from Green Guide To Go, 22 May 2007
Screen
Test: Reading the Micro-Fine Print
by Maureen Ryan
Filed under: Suncscreen, Sunscreen, Skin Care
With Memorial Day right around the corner, we have a lot to
look forward to: long, hot days, pool parties, barbecues, baseball games and
picnics in the park. But with these outdoor activities comes the very real
threat of the sun's dangerous—and deadly—rays: Ultraviolet-B (UVB) rays, known
to cause sunburn and associated with an increased risk for basal and squamous
cell cancers and melanoma skin cancer, and ultraviolet-A rays which
penetrate deeper into the skin, enhancing UVB’s carcinogenic effects.
In fact, approximately 90 percent of all skin cancers are
caused by sun exposure, and this year alone, the American Cancer Society
estimates that over 1 million Americans will be diagnosed with skin cancer and
more than 10,000 will die from it. And atmospheric scientists are concerned
that massive Asian sales of air conditioners, which rely on ozone-depleting
chemicals, bode ill for the hole in the ozone layer.
That information, coupled with research demonstrating that
sunscreen poses its own risks, is reason enough to scrutinize product labels.
Chemical sunscreens that absorb the sun's rays commonly
contain compounds that have been shown by numerous studies to interfere with
the body's hormonal systems. The most prevalent include benzophenone,
homosalate and octyl methoxycinnamate (also called octinoxate). Other chemicals
like padimate-0 and parsol 1789 (AKA avobenzone) have the potential to damage
DNA once activated by UV rays.
Mineral sunblocks that contain titanium dioxide (TiO2) or
zinc oxide (ZO) are preferable to chemical sunscreens, because rather than
being absorbed into the skin, the minerals lie on top of the skin, reflecting
UV rays before they cause damage. The choice of most lifeguards, these
sunblocks are famous for giving off that unattractive "white" mask.
But this is where problems with minerals arise. In order to
reduce the visibility of sunscreen, many manufacturers use nanometer-sized
particles of TiO2 and ZO. A nanometer (nm) is about a billionth of a meter—a
unit so small that a single human hair is about 80,000 nm in diameter. The
Nanoparticles are unpredictable because their small size and
high ratio of surface area to volume can produce chemical or physical
properties that are very different from their larger counterparts. For
instance, once TiO2 nanoparticles enter the bloodstream, they are at risk of
infiltrating the brain where they can damage cells, whereas larger micron-sized
(millionths of a meter) particles of TiO2 are blocked by the blood-brain
barrier, which protects the brain from harmful substances in the bloodstream.
Fortunately, the consensus in the scientific community, as demonstrated by a
2006 Australian government literature review on the topic, is that neither TiO2
nor ZO penetrate the skin deep enough to actually enter the bloodstream.
That's not to say that the Food and Drug Administration,
which hasn't assessed the safety of nanoparticles, can rest easy on
Further confusing the issue, some companies use the term
"micronized" to describe micron-sized particles, while other
companies use it to describe particles that undergo what some dictionaries
define as "breaking into very fine particles." Since the FDA has no
set definition for the term, some companies misleadingly advertise nano-sized
particles as "micronized," which is why it's important to verify
particle sizes when you're purchasing a product that contains
"micronized" or "nanoparticle" ingredients.
Nano-Free Suggestions
Because the studies present greater evidence against
chemical sunscreens, and because it's riskier to spend time outdoors with no
sun protection whatsoever, The Green Guide feels that mineral sunscreens
are the better alternative, in addition to common-sense measures such as
limiting time spent outdoors during peak sun hours and covering up with hats
and long-sleeved clothing.
To avoid confusion, we have only included products
containing TiO2 and ZO in micron-sized particles (1 micron or larger) or
nano-sized particles larger than 100 nm, which are too large to penetrate the
deepest skin layers. These are also free of The Green Guide's Dirty Dozen chemicals:
New for '07
Burt's Bees new Chemical Free Sunscreen SPF 15
with TiO2 ($15/3.5 oz.; www.burtsbees.com,
800-849-7112)
Alba Botanica Sun Fragrance-Free Mineral Sunscreen
SPF 18 with TiO2 ($9.95/4 oz. bottle, www.albabotanica.com, 877-263-9456).
Old Favorites
Avalon Organics Baby Avalon Natural Mineral Sunscreen
SPF 18, good for babies and adults with sensitive skin; the American Academy of
Pediatrics recommends keeping babies younger than six months out of direct
sunlight and only applying sunscreen when shade is unavailable ($9.95/3.5 oz.
bottle, www.avalonorganics.com,
877-263-9456)
EcoLani SPF 15 sunscreen with TiO2 also
contains micronized Green Coffee Extract, which reflects ultraviolet light
($15/4 oz. bottle, www.lanisimpson.com/ecolani).
JASON Natural Sunbrella Chemical-free Sun Block SPF
30+ ($19/6 oz) and Earth's Best Chemical-Free Sunblock SPF 30 for kids ($12.48)
with TiO2 and ZO (www.jason-natural.com,
877-527-6601).
Juice Beauty SPF 30 Tinted Moisturizer includes
organic white grape and pomegrante juices ($29/2 oz.) and the Green Apple SPF
15 Moisturizer contains a brightening hydroxy-acid complex of organic apple and
lemon juices ($38/1.7 oz; www.juicebeauty.com,
415-457-4600).
A Final Note: In January 2007, the FDA approved a
new sunscreen called Mexoryl SX, or ecamsule, for use in the U.S. Hailed by
dermatologists as a highly effective UV-A barrier, the only product in which it
is currently used is L'Oreal's Anthelios SX. However, to make the sunscreen a
broad-spectrum UV-A and UV-B protector, avobenzone was added, which, as
previously stated, may damage DNA.
Resources
Sunscreens and Sunblocks Product Report www.thegreenguide.com/reports/product.mhtml?id=27
For practical tips on sun protection, see www.greenerpenny.com.
"Nanoparticles: Small Ingredients, Big Risks,"
Friends of the Earth, www.foe.org/camps/comm/nanotech/
|
|