UVR Induced Melanogenesis Provides Photoprotection

UVR Induced Melanogenesis Provides Photoprotection

by Donald L. Smith

Editor's note:
LOOKING FIT decided to print the following article immediately rather than waiting until next month when it was scheduled due to its importance to tanning salon owners. The Gilchrest and Eller article was written by respected dermatologists and published in a prestigious medical journal. Moreover, the authors clearly state unambiguously that UVR-induced melanogenesis (better known as tanning) provides protection against acute (sunburn) and chronic (including skin cancer) skin damage. It will be interesting to see what the anti-tanning segment of the dermatology community has to say about this important article.

Mother Nature Knows Best

"Life on earth evolved in the presence of UVR irradiation from terrestrial sunlight and essentially all organisms developed photoprotective mechanisms to limit the resulting damage. In the case of human skin, two photoprotective mechanisms have been recognized. (1) Melanin pigmentation, both constitutive (baseline) and facultative (inducible), is the major recognized form of protection against UV-induced damage. Photoprotection is attributable to the fact that the melanin polymer can directly absorb UV photons, dissipating the otherwise injurious energy as heat, and can further absorb free radical species generated by interaction of UV photons with cellular lipids and other molecules that otherwise cause oxidative damage. (2) Scattering and reflection of UV photons by proteins in the statum cornenum is known to thicken following UV radiation, particularly in poorly melanized skin.

"Mammalian skin responds to UV irradiation by increased production of the pigment melanin in melanocytes with subsequent distribution to surrounding keratinocytes in a manner shown to be photoprotective. Also, recent data indicates that mammalian cells, like bacterial cells, have a UV-inducible DNA repair capacity that further protects the tissue from subsequent UV exposure. The combined effect of UV-induced melanogenesis and enhanced DNA repair capacity as well as possibly other as yet poorly elucidated inducible responses, is to render the skin far more resistant to subsequent UV injury. Such responses can reasonably be presumed important in protecting skin from acute and chronic UV damage including the development of skin cancer.

In addition, sun induced tanning is known to be photoprotective, with a sun protection factor (SPF) of approximately three to five, depending on the individuals genetically determined ability to tan."

The words above were not written by me, although they could have been because they substantiate my "science of tanning" rationale for the benefits of sensible, moderate and responsible exposure to UVR. Rather, they were written by Barbara A. Gilchrest, M.D. and Mark S. Eller, M.D., of the Department of Dermatology at the Boston University School of Medicine for an article published in the September 1999 issue of the Symposium Proceedings (1999) of the Journal of Investigative Dermatology.

What Does This Article Mean?

I believe this article is just the first of many that will, perhaps without meaning to, support the benefits of sensible, moderate and responsible exposure to UVR. This especially is true since this article was written by respected members of the dermatology community and published by a prestigious dermatology magazine. If they primarily are concerned about their patient's welfare it is counterproductive for the American Academy of Dermatology to continue ignoring evidence proving that the benefits of tanning far outweigh the minimal and manageable risks involved.

Summary Of Gilchrest And Eller Article

In summary, the Gilchrest and Eller article says:

• Both our natural skin color (constitutive pigmentation) and an acquired "tan" (facultative pigmentation) provide protection against UV-induced damage to the skin.
• UV photons directly are absorbed by melanin polymers which helps the body get rid of the otherwise injurious energy as heat and the melanin polymers also can absorb potentially damaging free radicals.
• The thickening of the stratum corneum during the tanning process also provides photoprotection, especially in individuals with lower phototypes/subtypes.
• Tanned skin becomes far more resistant (by a factor of three to five times) to subsequent ultraviolet radiation injury.
• The darkening of the skin during the tanning process and the enhanced DNA repair capacity that results (and possibly other unknown factors) can be presumed important in protecting the skin from both acute (sunburn) and chronic (including the development of skin cancer) UV damage.
• The "bottom line" is that it matters not whether an individual is born with darker natural skin color or acquires and maintains a "tan" at an indoor tanning salon, the photoprotective benefits are the same. According to Gilchrest and Eller, these benefits are not just limited to the prevention of erythema (sunburn), but specifically include preventing the development of skin cancer.

Salon owners, make copies of this article and give them to your skeptical clients when they question whether or not tanning provides photoprotection. Be sure to point out that this article was based upon material published in a prestigious dermatology journal that was written by respected members of the dermatology community.

The benefits of sensible, moderate and responsible exposure to UVR far outweigh the minimal and manageable risks, especially when one considers the benefits of photoprotection.

Donald L. Smith is executive director of The North American Alliance of Tanning Salon Owners (TSO), an organization dedicated to looking out for the best interests of tanning salon owners. For more information check out the Web site at www.naatso.org.