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Sunday, May 19, 2013
Skin Care and Diseases
Sun Beds and Safe Tanning?
As an opponent of sun beds I am faced with a dilemma. My family`s holiday is usually taken in France where the sun is not too intense. This year, we are holidaying in southern Portugal. As the sun is much more intense there I pose the question - would it be less harmful to gain a little induced protection using a sun bed prior to the holiday or to leave it to completely natural sun tanning - both using plenty of SPF 20 cream? I am a Biologist and would welcome your expert opinion. Those answeres on the web-site postulate the de-merits of sun beds for non-medical use. Is there are positive side in my case?
Your questions assumes that tanning prior to going on vacation has some protective value to prevent burn or sun damage when you arrive in Portugal. That may not be the case. First let me give you the positive side. I think that sunlight is not evil or bad. Nature requires that we get some sunlight for the formation of vitamin D that is essential for numerous functions in the body, just one of which is strengthening of bones. So clearly nature intends that we get some sun. The skin like all organs has limits. There is a lower limit of sun light below which we get rickets. There is an upper limit above which we get burned and sustain damage to our DNA that might lead to skin cancers and other manifestations of sun damage. So the principal is stay within one`s limits, get a little bit but don`t burn. Don`t lay out all day. The Greeks said it all about 500 BC. Moderation in all things is a sign of wisdom.
In fact the darkest skin in humans gives a sun protection of about 3 or 4. That means it permits enough sun to produce the benefits of sun but significantly reducing damage and probability of burning. But even very dark people can burn if exposed to enough sunlight. I lived in Tanzania for a year and noted that most natives spent the middle of the day indoors. Only the Caucasians were out ignoring the sun. I don`t think that the little tan you get in a tanning parlor will be of much value in preventing sunburn or damage to your DNA when you get to Portugal. But I don`t think that tanning parlors will do much damage to your skin if used in moderation. It seems more interesting and fun to get a slight, slow tan naturally by using sunscreens and avoiding long exposures to direct sunlight after you get to Portugal but that is a personal preference. It should be noted that the UVA in tanning parlors is not the proper spectrum for production of vitamin D, so the sun has a better spectrum for formation of vitamin D if that is a big issue for you. Or you might drink a glass of milk or two.
I think that the moderate, thoughtful and wise person will not burn but will not be lilly white. It is true that when they get older like me in the 60`s they might have a few keratoses and lentigines. But even that depends a great deal on the genetic background. Those of Celtic origin tend to get actinic and seborrheic keratoses, lentigines and other manifestations of sun exposure whereas other northern Europeans exhibit no such changes.
I don`t think that actinic keratoses are particularly dangerous. Only 40% of skin cancers are thought to arise in a keratosis. So most arise on normal appearing skin. And these cancers have a very low malignant potential. They almost never spread or metastasize. So a few keratoses is no big deal when one has achieved senior citizen status. And they are not related to melanomas which are dangerous and can be fatal. Melanomas on the other hand are related to severe burns with blisters. People of Celtic origin who have lots of moles and a family history of melanoma are especially at risk and should be very cautious about excessive sun exposure. For them I would recommend milk as a substitute source for vitamin D.
I hope this information is helpful and that you have lots of fun in Portugal and don`t ruin your vacation with painful sunburns.
James J Nordlund, MD
College of Medicine
University of Cincinnati