3 Things You May Not Know About UV Radiation - and Why You Should!
Posted Jun 05 2011 8:15pm
The American Cancer Society recommends four easy, fun, and safe sun habits: Slip, Slap, Slop and Speak out.
It all sounds so easy - grab a bottle of sunscreen, apply it, and you're safe to go out into the sun.
Unfortunately, it's not quite as simple as that, and what you don't know may be putting you, or your children, at risk of premature aging, or even potentially deadly skin cancer!
UVA vs UVB
Ultraviolet radiation is classified according to wavelength as UVC, UVB, or UVA.
UVC has the shortest wavelength, and is the most damaging - but it is completely filtered by the earth's atmosphere, so we don't have to worry about it.
UVB has the medium wavelength - it penetrates only the outer layer of the skin, the epidermis, and is responsible for tanning, and sun-burn, and skin aging, and skin cancer. Most of it is filtered by the earth's atmosphere - it is strongest mid-day during the summer months.
UVA has the longest wavelength – it was long considered to be safe, and is therefore what is used in sun-tanning studios. It has since been found to cause more damage to the body than UVB. UVA is not filtered by the earth's atmosphere, and is roughly the same strength all day long, year-round. It can penetrate light clothing, car windshields, office windows and hats ... It also goes through the epidermis, and penetrates the second layer of your skin, the dermis, accelerating the aging process by damaging both collagen and elastin, dilating blood vessels, causing age spots, and wrinkles. In addition, UVA rays are known to cause melanoma, a deadly skin cancer.
SPF (sun protection factor)
SPF is a measure of the effectiveness of a sunscreen in protecting against UVB radiation (an SPF of 15 means that, used properly, the user will require fifteen times as much UVB radiation before being sunburned as they would without the sunscreen on).
What is noteworthy is that an SPF rating says nothing about how much protection is offered against the more dangerous UVA radiation. Look for "Broad spectrum UVA/UVB" sunscreens containing zinc oxide (best), titanium dioxide, or avobenzone.
And be aware that some sunscreens that claim to be broad spectrum provide only limited protection from UVA radiation.
You may have heard arguments that using sunscreen is just as dangerous as NOT using sunscreen – on the one hand you have the possibility of getting skin cancer from too much UV exposure, while on the other hand there's the danger of getting cancer due to absorption of carcinogenic toxins contained in sunscreens!
Here is a list of some commonly used ingredients of sunscreens, and their safety ratings [Environmental Working Group] :
RETINYL PALMITATE (VITAMIN A PALMITATE) - cancer and reproductive toxicity
OXYBENZONE (Active Ingredient) - endocrine disruption, readily absorbed and persistent
Believed to be safe:
ASCORBYL PALMITATE (VITAMIN C PALMITATE)
AVOBENZONE (Active Ingredient)
HOMOSALATE (Active Ingredient)
OCTISALATE (Active Ingredient)
OCTOCRYLENE (Active Ingredient)
TITANIUM DIOXIDE (Active Ingredient)
ZINC OXIDE (Active Ingredient)
Interestingly, even many sunscreens marketed as being safe for children or babies contain potentially toxic ingredients. Check before you buy!
To make sure that your sunscreen is both safe AND effective - check it out at Environmental Working Group's Skin Deep cosmetics database, at http://www.ewg.org/skindeep