Dermatologist, Sunscreen and a Recipe for Skin Cancer Protection

Jacob Schor ND

March 17, 2009

I can think of no one I would rather have working over my naked body than my dermatologist.  She is bright as they come, fast, efficient and when she tells me a new splotch is nothing to worry about I believe her and leave her office happy.

 

Yet sitting in the exam room at the dermatology office yesterday I was distraught to read the posters on the wall exhorting use of sunscreen to prevent sun damage to the skin.  Distraught not because I’m a bit of a slacker when it comes to applying sunscreen but distraught because I thought medicine was evidence based these days.

 

At this point in time the scientific evidence no longer supports the use of sunscreen to prevent malignant melanoma.  This is counter-intuitive of course.  Not everything in medicine makes sense at first glance; after all we are talking about biology, an inherently messy business.

 

In the last dozen or so years a great many studies have been published that suggest vitamin D is protective against cancer.  Last time I checked PubMed listed 5, 300 something papers on vitamin D and cancer.  Nevertheless, even as these studies have appeared, the ‘skin experts’ have increased their exhortations to use sunscreen.  Sunscreens prevent the skin from making vitamin D.  I started wondering whether sunscreen’s protective action against skin cancer outweighs the decrease in vitamin D and loss of protection against other cancers?

 

We need some background numbers first to appreciate the situation.  Malignant melanoma is relatively rare.  It is responsible for less than 10,000 fatalities a year in the United States.  Other types of cancer cause far more fatalities.  Lung cancer causes about 150,000 deaths a year. Breast cancer about 40,000.  In all, about half a million people in the US die of cancer each year. 

 

 William Grant, a major vitamin D researcher, estimates that vitamin D deficiency allows 100,000 people to develop cancer each year who wouldn’t have if they had adequate levels to provide protection.  These cancers cause 40,000 deaths per year.    Cedric Garland concluded years back that 1,000 IU of vitamin D a day, decreases risk of colorectal cancer by half. Giving everyone a moderate dose of vitamin D could, in theory, prevent 28,000 colon cancer deaths a year.   Grant calculated that spending a billion dollars to provide 1,000 IU of vitamin D a day to every one in Europe and North America will save between $16-25 billion dollars in cancer care costs.   These numbers are estimates based on epidemiology.  In reality vitamin D may have an even greater effect.

 

In a prospective randomized placebo controlled trial on vitamin D published in June 2007,  Lappe reported that menopausal women taking 1,000 IU of vitamin D for four years  had a relative risk of 0.232 of getting cancer compared to the control group getting placebo.  Expressed in simpler English, taking vitamin D and calcium lowered these women’s risk of being diagnosed with cancer by 77%.

Given these sorts of numbers I wondered what would happen if we all were to stop using sunscreen; what would the trade off be?  How many more cases of skin cancer would we cause in trying to increase vitamin D naturally?  How useful is sunscreen?  Seeking a statistic, some measurement of sunscreen’s benefit yielded a great surprise. What I discovered was that apparently sunscreen doesn’t work.

In 1999, Martin Weinstock published the results of a meta-analysis of 13 epidemiological studies on the relation of sunscreen use to melanoma risk. Three studies showed a decreased risk of melanoma. Four showed an increased risk and six were inconclusive.   A 2002 review published in the British Journal of Dermatology yielded no more assurance that sunscreen is protective. The authors described their results as ‘discordant.' To quote their abstract: “Two case-control studies show a protective effect of sunscreen use, while three studies showed a significant risk associated with sunscreen use…” They found excuses to explain away the results suggesting sunscreen increased risk.  

 

A 2007 study in the Annals of Epidemiology tells us something we would prefer not to hear. Data from 17 different studies on sunscreen use were analyzed based on the latitude at which they were conducted. Of these, 10 studies were conducted at latitudes >40 degrees from the equator and 7 at < 40 degrees.  When all the data were combined together no protective effect was seen against skin cancer.  Analyzing the data based on latitude yielded an interesting result.

 

In studies conducted at latitudes > 40 degrees from the equator, sunscreen use increased risk.  The odds ratio of getting skin cancer increased to 1.6 times average. In simpler words people were about one and a half times as likely to get cancer.  Below 40 degrees latitude, sunscreen use lowered skin cancer risk ratio slightly.  

 

This is especially relevant to our readers in Denver.  Denver’s latitude is 39.7391667 degrees.  We’re as close to exactly on the 40 degree line as you can get.   Sunscreen may not increase risk for us but it probably doesn’t help.

 

Sunscreen is designed on purpose to block UV penetration into the skin. That is why it prevents sunburn. This is also why it prevents production of vitamin D. Even relatively weak sunscreens labeled SPF-8 will block UV and stop vitamin D production.

 

Even if sunscreen doesn’t protect against skin cancer, why would it increase risk?  The explanation is simple.  Most chemical sunscreens block ultraviolet B (UVB) but are transparent to ultraviolet A (UVA).  More than 90% of the ultraviolet light from the sun is UVA.  Sunscreens work very well to prevent your skin from getting red or sunburned.   They allow us to stay out in the sun much longer than we would if we were getting burnt. As a result the skin ends up damaged more than if we hadn’t used sunscreen.

 

The real explanation may actually be a bit more complex. Kerry Hanson at the University of California exposed human skin samples grown in the lab to UV radiation while supposedly protected with the chemicals commonly used in sunscreens. One hour later, each compound had soaked into the skin, reducing its protective effect. This finding gave rise to the news reports suggesting that you need to reapply sunscreen every two hours.

 

These news stories missed the important part. The skin samples that were supposedly protected by sunscreen contained more reactive oxygen species (ROS) than skin with no sunscreen on it. ROS are free radicals that damage skin cells and increase the risk of skin cancer.

 

Why would sunscreen use be beneficial below 40 degrees latitude and harmful above? The lower the latitude the more sun someone is exposed to.  Is it that with the more intense sun exposure sunscreen works better?  My suggestion that the answer is something else.  The further south someone lives the more sun exposure and the tanner someone gets, whether they use sunscreen or not.  Could the actual process of getting tan be protective?  Perhaps.

 

UV exposure activates production of p53 enzyme that in turn activates the tanning pathway. Skin cells without the p53 gene will not tan. This is the gene cells use to trigger apoptosis (cellular suicide) when they detect an insurmountable level of genetic damage.  In other words, the p53 enzyme is how cells kill themselves when they realize they have become cancerous. Cells without active p53 cannot protect themselves against cancer. Cells with working p53 enzymes will usually kill themselves if they become cancerous. Turning on the p53 gene through sun exposure may also turn on the cancer fighting potential of both the skin and the body.

If sunscreen doesn’t work, why isn’t anyone talking more about it?  Maybe this is like the Han Christian Andersen’s story about the Emperor’s New Clothes.  He was convinced he was wearing a fine suit of magic clothes.  The magic cloth was invisible to stupid people and no one wanted to admit they couldn’t see it.   The emperor paraded around town naked;  everyone was afraid to say anything for fear of looking stupid.

Sunscreen probably doesn’t work to prevent malignant melanoma.  There’s no question that it stops sunburn though. There is no question that sunscreen is useful when Spring skiing at A-Basin.  Without it one would be burnt to a crisp. 

 

Still it is no miracle cure to prevent skin cancer.  We’ve got to use something else. The best way to protect the skin from sun damage is to keep skin covered in bright sunlight and to prevent damage from sun exposure with antioxidant vitamins and polyphenol plant extracts. 

 

Sun damage is oxidative damage and there are clear studies that show that vitamins and plant extracts can reduce oxidative damage due to UV radiation providing protection against skin cancer.   Radiation damage increases generation of reactive oxygen species in the skin cells. Various phenolic compounds and flavonoids that we are already familiar with will quench these oxidative species and can be used to provide protection.

 

The best way to get these compounds to the cells that need them the most is by topical application. An article from 2004 in the Journal of Cosmetic Dermatology tells us that:

 

  “There are two great advantages in applying an active formulation of topical antioxidants to the skin. First, the skin attains far higher levels of each antioxidant than can be achieved by only taking these vitamins orally. The level of vitamin C attained in the skin by topical application is 20-40 times that achievable with oral vitamin C. With topical application, the concentration of vitamin E in the skin increases by a factor of 10.6 and selenium by a factor of 1.7. Second, topical application arms the skin with a reservoir of antioxidants that cannot be washed or rubbed off, a protection which stays in the skin for several days after application.” 

 A variety of things have already been studied that work. Vitamin C, Vitamin E and selenium as the article says help heal sun damage to cells. Vitamin E is very protective, especially in combination with selenium.   Green tea extracts also prevent damage. Actually, quite a few plant extracts appear to be protective. If you are making a list, add milk thistle, grape seed extracts, pomegranate extracts,   caffeine, and Cat's Claw.

That article by Burke I quoted earlier pretty much lays out a basic recipe for a sun protecting lotion:

“For effective topical application, vitamin C must be non-esterified, acidic and optimally at 20% concentration; vitamin E must be the non-esterified isomer d-alpha-tocopherol at 2-5% concentration. Selenium is only percutaneously absorbed and active when applied topically as l-selenomethionine, optimally at 0.02-0.05%.”

 

I’m thinking of this as I leave the dermatologists office.  Across the street is a small pharmacy that does a fair amount of custom compounding.  How hard would it be for them to mix up some of this mixture?  In fact, let me confess, I’m writing this newsletter with them in mind.

 

At this time no one seems to be making a product containing actual therapeutic doses of these supplements.  No problem, it is easy enough to make up your own.  Pick whatever topical cream you like to use, a moisturizer, sunscreen etc, and open up a few capsules of any of these vitamins and plant extracts, and mix them in.  Let’s do some simple math:

 

For every 100 ml of lotion (about 3-4 ounces), add:

Vitamin C   20 grams

Vitamin E  2-4 grams

Selenium 0.0002-0.0005 grams which is 200-500 mcg

 

Doses on the plant polyphenols are less defined but a gram or more will increase the benefit. Your cream will have thickened to a paste but no worry.

 

Since we already have all this stuff on the shelf, I’ve simply opened capsules.  Another approach is to purchase these ingredients, including a topical cream base on the web from: http://www.skinactives.com/

 

You’ve just created a topical antioxidant mixture to treat and prevent sun.  It doesn’t stop the sun’s damaging rays from penetrating the skin but it may protect the cells from oxidative damage caused by the sun’s ultraviolet radiation.  Use this fortified skin cream on sun exposed skin daily, especially before and after intense sun exposure. It won’t prevent sunburn but it may eventually be proven to prevent skin cancer. 

 

 

 

Grant WB. An estimate of premature cancer mortality in the U.S. due to inadequate doses of solar ultraviolet-B radiation. Cancer. 2002 Mar 15;94(6):1867-75.

  Gorham ED, et al Optimal vitamin D status for colorectal cancer prevention: a quantitative meta analysis. Am J Prev Med. 2007 Mar;32(3):210-6.

Grant WB. An estimate of cancer mortality rate reductions in Europe and the US with 1,000 IU of oral vitamin D per day. Recent Results Cancer Res. 2007;174:225-34.

Lappe JM  et al. Vitamin D and calcium supplementation reduces cancer risk: results of a randomized trial. Am J Clin Nutr.  2007 Jun;85(6):1586-91.

Weinstock MA. Do sunscreens increase or decrease melanoma risk: an epidemiologic evaluation. J Investig Dermatol Symp Proc. 1999 Sep;4(1):97-100.

Bastuji-Garin S, and Diepgen TL Cutaneous malignant melanoma, sun exposure, and sunscreen use: epidemiological evidence. Br J Dermatol. 2002 Apr;146 Suppl 61:24-30.

Gorham ED, et al. Do sunscreens increase risk of melanoma in populations residing at higher latitudes? Ann Epidemiol. 2007 Dec;17(12):956-63.

Grant WB. An estimate of premature cancer mortality in the U.S. due to inadequate doses of solar ultraviolet-B radiation. Cancer. 2002 Mar 15;94(6):1867-75.

Garland CF, et al. Rising trends in melanoma. An hypothesis concerning sunscreen effectiveness. Ann Epidemiol. 1993 Jan;3(1):103-10.

New Scientist magazine, 09 September 2006 , page 16

Cui R, et al. Central role of p53 in the suntan response and pathologic hyperpigmentation. Cell. 2007 Mar 9;128(5):853-64.

Nan H, et al. Interaction between p53 codon 72 polymorphism and melanocortin 1 receptor variants on suntan response and cutaneous melanoma risk.

 Br J Dermatol. 2008 Aug;159(2):314-21

Box NF, Terzian T. The role of p53 in pigmentation, tanning and melanoma. Pigment Cell Melanoma Res. 2008 Oct;21(5):525-33.

Sies H, Stahl W. Nutritional protection against skin damage from sunlight. Annu Rev Nutr. 2004;24:173-200.

Svobodova A, et al. Natural phenolics in the prevention of UV-induced skin damage. A review.  Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub. 2003 Dec;147(2):137-45.

Burke KE. Photodamage of the skin: protection and reversal with topical antioxidants. J Cosmet Dermatol. 2004 Jul;3(3):149-55.

Burke KE et al. Effects of topical L-selenomethionine with topical and oral vitamin E on pigmentation and skin cancer induced by ultraviolet irradiation in Skh:2 hairless mice.

 J Am Acad Dermatol. 2003 Sep;49(3):458-72.

 

Mittal A  et al.  Exceptionally high protection of photocarcinogenesis by topical application of (--)-epigallocatechin-3-gallate in hydrophilic cream in SKH-1 hairless mouse model: relationship to inhibition of UVB-induced global DNA hypomethylation. Neoplasia 2003 Nov-Dec;5(6):555-65.

Dhanalakshmi S et al. Dual efficacy of silibinin in protecting or enhancing ultraviolet B radiation-caused apoptosis in HaCaT human immortalized keratinocytes.

 Carcinogenesis. 2004 Jan;25(1):99-106. Epub 2003 Oct 10.

Mittal A et al. Dietary feeding of proanthocyanidins from grape seeds prevents photocarcinogenesis in SKH-1 hairless mice: relationship to decreased fat and lipid peroxidation. Carcinogenesis. 2003 Aug;24(8):1379-88. Epub 2003 Jun 05.

Syed DN et al. Photochemopreventive effect of pomegranate fruit extract on UVA-mediated activation of cellular pathways in normal human epidermal keratinocytes.

Photochem Photobiol. 2006 Mar-Apr;82(2):398-405. 

Lu YP  et al. Caffeine and caffeine sodium benzoate have a sunscreen effect, enhance UVB-induced apoptosis, and inhibit UVB-induced skin carcinogenesis in SKH-1 mice.

Carcinogenesis. 2006 Jul 24;

Mammone T et al. A water soluble extract from Uncaria tomentosa (Cat's Claw) is a potent enhancer of DNA repair in primary organ cultures of human skin. Phytother Res. 2006 Mar;20(3):178-83. 

Burke KE. Photodamage of the skin: protection and reversal with topical antioxidants. J Cosmet Dermatol. 2004 Jul;3(3):149-55.

 


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