The Doctor Is In: Can Tanning Prevent Cancer?
When it comes to getting high levels of vitamin D, is baking in the sun just as good as drinking a tall glass of milk?
Q: I read that vitamin D from sunlight prevents cancer. Are tanning beds even better?
Should I stop wearing sunscreen?
A: That question is the subject of heated discussions among dermatologists and medical researchers. Sunscreen and tanning bed manufacturers also have strong opinions, along with vitamin distributors and cancer awareness foundations.
Boston University’s Dr. Michael Holick created a firestorm among dermatologists in November 2007, when he published a book promoting the use of sunlight to combat vitamin D deficiency that he believes is epidemic in modern society.
Dr. Holick, an endocrinologist with a PhD in addition to his medical degree, is no heretic. His studies on vitamin D have pioneered treatments for chronic health conditions like psoriasis. But he has been criticized for his acceptance of six-figure funding from the tanning bed industry. He counters that sunscreen manufacturers have aggressively funded his detractors’ research.
The controversy stems from the behavior of vitamin D. A number of studies suggest an association with low levels of vitamin D and higher rates of breast, colon, and prostate cancer. Vitamin D may act as to slow the growth of blood vessels that “feed” a tumor. Vitamin D also appears to affect the immune system and is essential to the function of muscles.
There is conflicting evidence on the best way to achieve ideal levels of the vitamin, whether through diet, supplements or — this is the tricky part — ultraviolet rays.
Few foods naturally contain high levels of vitamin D. Fish are a good source, and commercially-available milk is supplemented in the United States. But there is a question whether typical American diets provide adequate vitamin D, or even what level constitutes “enough.”
When ultraviolet light from sun or tanning bulbs hits the skin, the body makes Vitamin D.
But sun exposure — particularly prolonged exposure leading to sunburns — has a clear relationship to the development of many common skin cancers. People with a family tendency are at even higher risk of the rare but potentially lethal melanoma-type skin cancers.
The issue becomes more complicated when taking into account the other effects of the vitamin, which is clearly effective in preventing osteoporosis. The impact of decreased bone fractures in those taking calcium/vitamin D supplements is weighed against the known increase in kidney stones and calcium-related complications.
Less medically relevant but of importance to many people is the fact that sun exposure causes skin damage and premature aging. Wrinkled, leathery skin in reformed sun worshippers has created a multi-billion dollar anti-aging industry.
So should you bake or take cover?
As usual, no one answer is a perfect fit. Maximum vitamin D production by the skin happens after a brief period of exposure — as few as two minutes for a fair-skinned person in the summer sun. Exposure to ultraviolet rays for 5-30 minutes no more than three times per week is adequate to achieve appropriate Vitamin D levels, a recommendation made by its greatest champion, Dr. Holick.
But before rushing out to the beach without a hat, keep in mind that even brief exposures, such as those from walking through a parking lot, “count” against this weekly recommendation. The amount of sunscreen needed to effectively block ultraviolet rays is more than what typical users apply. And because vitamin D is stored in fat, adequate summer exposure may supply winter needs.
So exercise caution and let moderation and personal risk factors be your guide. Sunburns are a clear signal that even if a little is good, a lot may not be better.
Dr. Linda Halderman was a Breast Cancer Surgeon in rural central California until unsustainable Medicaid payment practices contributed to her practice's closure. She now serves as a policy advisor in the California State Senate.
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14 Comments
1. Jeff Perren:A balanced, objective report. Bravo, and thanks.
Jun 22, 2008 - 10:41 am 2. tanstaafl:Tanning doesn’t prevent cancer. Vitamin D production in the skin by a few minutes/day exposure to the sun’s rays likely plays a role in cancer suppression.
Excessive tanning and/or tanning beds seem to me macabre, especially when you see “old skin” that has been subjected to same over a lifetime.
However, the human organism and sunlight are a natural pair. I am convinced (on no particular evidence) that Vitamin D produced in the human body through the skin’s exposure to sunlight is the most useful form of the Vitamin.
I am also convinced that one of the true downsides of women wearing the Burkha (aka “the black bug suit”) is blocking exposure to sunlight. This might be particularly troublesome for women wearing the garment in northern, low sun climes, like the north of England.
In Saudi Arabia and other desert countries, the biggest health problem might be simply suffocating in 100+ degree heat.
Another interesting topic is that wearing sunscreen and preventing cancer (esp. the deadliest form of skin cancer, Melanoma) do not, necessarily, go hand in hand.
Jun 23, 2008 - 6:18 am 3. Sandra M:I read this research and began going out in the sun half an hour a day a couple of weeks ago (I have breast cancer). I have been feeling better as a consequence of the sunbathing and have more energy.
A friend giving me a massage yesterday guessed my age as late 30’s. I’m 73. I have an unwrinkled face thanks to the advanced science of Durk Pearson’s book, LIFE EXTENSION. Pearson’s book also has an excellent section on fighting the Food and Drug Administration. Pearson is an MIT grad, had 3 majors, and is a Libertarian.
Jun 23, 2008 - 7:23 am 4. Kay:I hope this is all private money used for study after study with the inevitable conclusion that we really don’t know much about anything when it comes to health and diet.
Jun 23, 2008 - 3:28 pm 5. AgingMom:Blacks have higher cancer death rates than whites, and this is usually chalked up to worse access to health care. But in a lot of black neighborhoods, the crime is so bad that people avoid going outside. Since darker-skinned people need more sunlight to produce adequate levels of Vitamin D, and since many blacks are lactose-intolerant and therefore consume a lot less in the way of dairy products than white people do, it may be that the black cancer rates really don’t have much to do with health care access, and a lot to do with a greater Vitamin D deficiency.
Jun 23, 2008 - 7:08 pm 6. ZEITGEIST:[...] CAN TANNING prevent cancer? [...]
Jun 23, 2008 - 7:18 pm 7. Ken Mitchell:There is a simple rule that everyone should remember; the Goldilocks Rule of Everything. For everything, there is a level which is “too much”, a level which is “not enough”, and a level which is “just right”.
Not enough oxygen will kill you. Too much oxygen will kill you. (One of my pilots in the Navy had to be reassigned from A-6 attack aircraft to P-3 patrol planes, because in the A-6 you have to wear an oxygen mask all the time, and in the P-3, you don’t. And if you try SCUBA diving with an oxygen bottle…. Well, you’ll only try it once.)
Not enough water, and you die of dehydration. Too much, and you drown.
Salt; you need some, but too much …..
Sunlight; too much gives you cancer. Not enough and you get rickets.
Botulism toxin will kill; BoTox smooths out movie stars’ wrinkles.
Curare is the poison that Amazonian warriors use for their arrows. But in the proper doses, curare stops the heart just long enough for surgery.
Pick something - ANYTHING. Follow the Goldilocks Rule, and you’ll be OK.
Jun 23, 2008 - 7:24 pm 8. Queenie:I spent my teens, 20’s and 30’s staying out of the sun, and I admit it kept me looking younger… but this year, the year of my 40th birthday, I decided to let myself sit out in the sun a little while every day. What the heck, I’m 40 now, right? Well, I have absolutely loved my 10-15 minutes a day (I confess to still wearing sunscreen on my face, and a hat). I look SO much better with color, (though I do think if I’d been doing this for years I might have that leathery Clint Eastwood look). I feel better, too.
The most interesting part, though, is that my nails have gotten so strong, that for the first time in my life it’s easier to let them grow out and be manicured that to bite/cut them off as they break. I’ve never been able to grow long nails before… they look nice!
I don’t know exactly what the sun’s doing, but it’s doing something…It may be unrelated, but I like to think that if my nails are getting demonstrably stronger, maybe my bones are, too?
Jun 23, 2008 - 7:30 pm 9. Ben:“There is a simple rule that everyone should remember; the Goldilocks Rule of Everything.”
Tell me, how many times shooting yourself in the face would be “just right”?
Jun 23, 2008 - 8:15 pm 10. Ken Mitchell:Typically, none - unless there’s a cougar trying to eat your nose. Then the correct answer might be “one”. The “Goldilocks Number” for most things depends on circumstances, but you probably already knew that. More generally, what’s the proper number of firearms that you should own? As many as you need, but not more than you can handle safely. Somewhere between one and the number that you can afford.
The same thing goes for most recreational pharmaceuticals; the proper dose of opioid drugs would be very low - but then, the curare in my example falls into the same category. The physician will prescribe the “proper” amount - but he may be wrong.
Jun 23, 2008 - 9:48 pm 11. JLawson:Ben -
I’d say ‘0′ on that, unless you’re a masochist with a BB gun…
Jun 23, 2008 - 10:11 pm 12. John Davies:>Tell me, how many times shooting yourself in the face would be “just right”?
Zero. -1 is much too infrequent.
Jun 24, 2008 - 12:29 am 13. Craig:I have always had a problem with the “no sun rule” especially for people of darker complexion who live in the northern climate, human evolution was in the sun. I think something else is going on, something in our diet we are eating or not eating.
Jun 24, 2008 - 7:18 am 14. Patterson:I know you may be joking Ben but no one said the Goldilocks rule was “idiot proof”.
Jun 26, 2008 - 8:45 am