Monday, June 23, 2008

Can Using Sunscreen Cause Cancer?


When I was in high school and college, I spent my summers as a lifeguard. Exposing my skin to the sun was an occupational hazard. Fortunately, I tan very dark but I still covered up with hats, umbrellas, sunglasses and sunscreen. Little did I know that sunscreen would protect me from getting burned but would not protect me from getting cancer.

Suscreen came on the scene in the 1940's. Improved tanning lotions came on the market in the early 1960s, and a few years after that, the
melanoma rate zoomed up (refer to the chart on the left). Sales figures jumped from $18 million in 1972 to $500 million in 1996. Public health authorities became concerned, and melanoma became news. Seeing a commercial opportunity, the makers of tanning lotions repositioned their products as "sunscreen," and the now familiar sermonizing began. Since then, melanoma has become the nation's fastest-rising cancer and sunscreen sales have continued to climb. Ozone depletion may play a role in the higher melanoma rate, as some scientists say, but melanoma cases began to go up long before ozone depletion became an issue.

There are three main kinds of skin cancer: basal cell, squamous cell, and malignant melanoma. The first two are common (about 1 million cases a year) and almost always medically minor. The American Cancer Society and the National Cancer Institute don't even count them in the nation's cancer statistics. Melanoma is much less common (40,300 diagnoses last year), but often fatal (7,300 deaths).Of the three different kinds of skin cancer, malignant melanoma causes the most concern. If not caught in time, it can metastasize (spread destructively) easily and is often fatal.

According to a survey of new research by epidemiologist Marianne Berwick of the Memorial Sloan-Kettering Cancer Center in New York, there is no evidence that sunscreen offers any real protection against malignant melanoma, the most dangerous form of skin cancer. "It's not safe to rely on sunscreen," Berwick told the press.

The first thing to know: Ultraviolet light from the sun comes in several wavelengths: UVA, UVB and the rarely discussed UVC (which is blocked out by the Earth's ozone layer). UVB, which damages the outer layer of the skin, has been recognized for decades as the cause of sunburn and as a major contributor to skin cancer and skin aging. UVA rays — while not contributing to sunburns — damage deeper layers of the skin and probably play an important role in wrinkling, spotting, lost elasticity and, most ominously, the dangerous skin cancer melanoma.

When sunscreens were developed, they were made to prevent sunburn and targeted only UVB. An SPF number refers to the UVB burning protection a product offers (one with an SPF of 15, used correctly, allows the user to stay in the sun 15 times longer without burning). So, instead of staying in the sun for 30 minutes, you could stay in the sun for 7.5 hours. Thinking that you are safe, you unknowingly expose your skin to damaging UVA rays for an extended period of time. By blocking the UVB rays, you block your skins ability to produce vitamin D which could prevent cancer and you are letting in dangerous amounts of UVA rays that could promote cancer. Although scientists have known for several years that UVA penetrates more deeply into the skin than UVB, they believed that less of it was absorbed by DNA, causing fewer dangerous mutations. However, an Australian-US study shows that UVA causes more genetic damage than UVB in skin cells where most skin cancers arise - the keratinocytes in the basal layer of the epidermis. UVB tends to cause damage in more superficial epidermal layers.


Even if sunscreen blocked UV-A completely, almost no one uses it in the way that grants real protection against sunburn. For sunscreen to live up to its hype, you have to slop it on real thick and reapply it every few hours. We're talking at least one full bottle per person per day at the beach. Meanwhile, the vast majority of sunscreen users apply a thin layer once or twice.

Around 1981, an ingredient called "Avobenzone" (Parsol 1789) was developed . It was an additive to sunscreen that was designed to block some of the dangerous UVA rays. The only problem with it is that it broke down in the sun and had to be reapplied constantly. Now there are additives that have increased it's stability such as mexoryl, octocrylene and oxybenzone. These have increased the protective abilities of sunscreen but at what cost to the health of your body and skin?


A team of researchers from the University of California has found that sunscreen can do more harm than good once it soaks into the skin. The sunscreen is supposed to be applied as a layer on the skin. When it is rubbed in, it penetrates to the deeper layers and promotes formation of harmful compounds. Thus sunscreens ironically cause the same damage against which they are meant to protect. Further, the chemicals present in commercial sunscreen products have also been found to be toxic and said to actually promote some forms of cancer.

Click on the following link to watch a short news clip from CBS about many of the toxic chemicals that are found in our personal care products.

CBS NEWS - Sunscreen Concerns

The sunscreen lotion is usually massaged into the skin. It penetrates into the deeper layers. The chemicals in the sunscreen are acted upon by the cells in the skin to produce free radicals and superoxides. These damage the skin structure and function resulting in aging.

What's even worse is the fact that both chemical sunscreens (methoxycinnamate, padimate-o and the like) and physical sunblocks (titanium dioxide and zinc oxide) generate free radicals when exposed to sunlight, which then can attack the nuclei of your skin cells and cause mutations. That's right: they can cause skin cancer. Furthermore, sunscreen chemicals have been found to pass through the skin and mimic the effects of estrogen, which may disrupt the delicate balance of the body's natural hormones.


Titanium dioxide is now being used as a new treatment for window glass because it attacks and degrades anything that touches it, thereby helping to keep windows clean. You probably don't want to have anything attacking your skin! My recommendation: Loose-fitting clothing, big hats and shady trees.

The only proven way to prevent melanoma is to cover up. Our forebears did so in the days before sunscreen. Clearly it worked because melanoma was so rare. It's also what people now do in Australia. White Australians come largely from light-skinned British/Irish stock. Queensland province, in northeastern Australia, has the highest melanoma rate in the world, but as the SCF proudly pointed out when it rebutted Berwick's study, melanoma rates there have started to flatten. What the SCF did not mention is that while the Queensland public health authorities began a big-budget PR campaign promoting sunscreen in 1981, they shifted the campaign's focus a few years ago to strongly encourage people to cover up and stay in the shade.


Another problem with sunscreen and sun avoidance is that UVB rays are responsible for creating vitamin D in our body. Sunscreens with a sun protection factor of 8 or greater will block UV rays that produce vitamin D. If you’re young, fair, scantily clad and near the equator, 10 to 15 minutes of peak sunshine produces 20,000 IUs if vitamin D.

There is a growing body of evidence that a higher intake of vitamin D may be helpful in the prevention and treatment of cancer, high blood pressure, fibromyalgia, diabetes mellitus, multiple sclerosis, and rheumatoid arthritis and other diseases.

Vitamin D works inside the cell nucleus as a basic building block to help turn genes on or off. Starting in the 1970s, researchers began finding the receptor for vitamin D in a huge variety of cells that have nothing to do with bone growth, including breast, colon, lung, brain, prostate and white blood cells. More recently studies using DNA chips have found that vitamin D can raise or lower the activity of at least 1,000 genes, says McGill University molecular biologist John White.

How vitamin D might ward off cancer is murky. But it's known that vitamin D stimulates white blood cells to produce a powerful natural antibiotic called cathelicidin. In the Mar. 24, 2006 issue of Science, scientists led by ucla dermatologist Robert Modlin found that when white blood cells were mixed with blood serum samples from African-Americans (who are prone to low vitamin D levels), they produce 63% less of this antibiotic than if the cells were mixed with blood samples from Caucasians. So, says Georgetown University immunologist Michael Zasloff, "Vitamin D has the capacity to turn on powerful antimicrobial genes." He predicts there will be new ways of staving off infections by modulating vitamin D levels.

So, getting a little unfiltered sun on your body is not a bad thing as long as it is done in moderation. It is a good thing. Your skin can handle it. The trick is not to get a sunburn. It is like alcohol consumption. A glass of wine with dinner can provide antioxidants and resveratrol which is very good for your body. Your liver can handle that but four bottles of wine is way to much and can lead to health problems.

Here are some tips for safe sun exposure:



  • Look to get at least 20-30 minutes of unfiltered sun on as much of your body as you can every day. Regular and moderate unprotected sun exposure in the early morning or late afternoon will help maintain a protective tan and keep your vitamin D stores at an optimum level.

  • Do Not try to get a tan by visiting a tanning studio. The rays from their UV lamps are extremely harmful and the tan produced does not have the protective effect of a sunlight-induced tan.

  • A sunblock with SPF 8 reduces the skin’s vitamin D production by 95 percent. Getting a sun tan through glass does the same thing. If you wear sunscreen ‘properly,’ you’ll become vitamin D deficient.

  • DO wear protective clothing and a wide-brimmed hat when you are outside. Avoid sun exposure between 10 AM and 3 PM if at all possible. Remember that UV rays, particularly UVA, are present even on cloudy days.

  • DO wear sunglasses that filter out 100% of the ultraviolet light to protect yourself against the development of cataracts.

  • DO make sure you get enough vitamin D3 and beta-carotene, if necessary through supplementation. Recent research has shown that taking 30 mg of beta-carotene a day protects against the suppression of the immune system by UVA rays.

  • DO make sure to supplement your diet with antioxidants. Vitamin C, vitamin E, and selenium can be used as a protection against the damages of excessive ultraviolet radiation. Try to get daily dosages of 1000 mg or more of vitamin C, 800 IU of vitamin E, and 200 micrograms of selenium (l-selenomethionine). Vitamins C and E also protect against cataract formation.

  • Cut down on the fried foods and saturated fat in your diet. Recent research has shown that patients with non- melanoma skin cancers can reduce their risk of developing additional actinic keratoses (precursors to skin cancer) by switching to a low fat diet. Use healthier oils like Olive oil, coconut oil, walnut oil or grape seed oil.

  • DO cover up by wearing a wide brimmed hat or a physical sunscreen with a SPF of 15 if you absolutely must be out in the sun for extended periods of time. Physical sunscreens containing titanium dioxide, zinc oxide, or talc work by reflecting the UV radiation rather than by absorbing it. Sunscreens that are tested by using artificial UV light and a screen with a SPF of 30 are not twice as effective as one with a factor of 15. Also, reapplying sunscreen during the day does not extend the period of protection. Even "broad-spectrum" sunscreens are not very good in filtering out UVA rays. A natural suntan is probably more effective.

  • DO see your health care provider if you spot any unusual moles or growth on your skin - particularly if they are irregular in shape, bleed, itch, or appear to be changing. Most skin cancers can be cured if caught in time.
*If you would like to check your suntan lotion or any other personal care products to see if there are any harmful chemicals in them, go to www.cosmeticdatabase.org

Here is a list of the top ten sunscreens according to the Skin Deep Cosmetic Safety Data Base. Click Here to read.

Helpful Sources:

Creighton Study Shows Vitamin D Reduces Cancer Risk


5 comments:

Keith said...

a very interesting post, gave me a lot of food for thought. I had not (consciously, anyway) made any linkage between greater use of sunscreen (by the way, I also remember in the 1960s them being touted as suntan lotion, not sun "screen" -- I also remember girls in the 1960s putting baby oil on their skin to tan quickly! yikes!) and the rise of skin cancer... I'm now going to take a look at skin cancer rates in Latin America and the Caribbean (the focus of my blog) and sunscreen usage there, see what I find out. Thanks for sparking my curiousity...

A. said...

It's quite frightening really to think that the sunscreens may do more harm than good. I too remember people using oil for sunbathing...

Luanne said...

Thanks for this eye-opening information. I have indulged in the past suntanning without protection, using oil, like Keith mentioned in his post and even have gone to the tanning beds.

I know the harm the sun can do but I still like having some color in the summer. I will have to pay more attention as to how I get my color.

liza said...

great info jeff! i've always thought sunscreens are safe.

i have written an article about broccoli as a very effective sunscreen but it's not out in the market yet. using the juice of the veggie is safer but the color green will stay in your skin for days. researchers are still trying to figure out how to eliminate the color.

i just hope it'll be out soon. i wish i could give you the link of that article but my site is down right now (http://mlizcochico.com).

happy weekend ;)

Wilmaryad Ben O'Scallas said...

Hello :-)
Your blog is so interesting and informative that I had to add it to my favorite blogs on my own.

Keep up the good work!