Author’s note (6/19/2014): This article is a rewritten version of the one published on June 14, 2014. The media adviser for SunSmart at Cancer Council Victoria reached out to let me know that the Nautilus article – the main source for my original piece – contained some inaccuracies. Below is a corrected article, including some of the comments from the email that I received.
Is moderate sun exposure healthy or unhealthy?
In my original article, the take-away was that a little bit of sun might actually protect us from skin cancer rather than cause it. The real problem seemed to come in not when you tan a bit but when you let that tan turn into a sunburn. After receiving an email from Cancer Council Victoria with corrections, I decided to dig in and look more closely at the science of sun exposure. What I found was very nuanced and not always consistent.
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Cancer Council Vitcoria (CCV) and The American Academy of Dermatology (AAD) both point to research indicating a link between UV exposure from the sun and skin cancer. You can read the AAD open letter to the editor of the Nautilus piece here.
In her email to me, the media adviser for SunSmart at Cancer Council Victoria said:
“We believe your article is incorrect in stating that the advice that skin cancer researchers and dermatologists would give anywhere would be ‘tan a bit, donít burn.’ There is no such thing as a healthy tan Ė a base tan certainly cannot be compared to ‘natural sunscreen’. Tanning is a photo protective response to UV-induced DNA damage, which results in pigmentation darkening due to increased melanin in the epidermis. It is a sign that skin damage, which could lead to cancer, has already occurred.”
That seems to mirror what the AAD letter says.
The SunSmart take on UV exposure and skin cancer, though, is a little bit less rigid than the AAD line, though. CCV’s SunSmart advises Australians that it’s OK to go sunscreen free during the winter, when UV levels are below a 3 on their scale. They even have a tool on their main page where Australians can look up the UV level in their area to see whether they need sunscreen or not. Here in the U.S., you can check your area’s UV index using this tool from EPA.
The Pros and Cons of Sun Exposure
While I definitely respect the CCV and AAD, I also respect writer Jessica Seigel. She’s a seasoned journalist, and her article was well referenced. I did a little bit of digging into the pros and cons of sun exposure.
There is a cost for too much sun exposure but there’s also a cost of too little. Too much sun leads to sunburns and can cause skin cancer. But too little sun exposure is linked to vitamin D deficiency. And vitamin D deficiency has more negative health effects – like rickets, certain cancers, and possibly multiple sclerosis – than overexposure to the sun.
Does that mean that you should go sunscreen free at the beach this summer? No. It means that the science of sun exposure isn’t black and white. Vitamin D is the “sunshine vitamin,” and our bodies synthesize it with the help of UVs. If you’re avoiding the sun, you may need to take a vitamin D supplement to avoid the problems that come with a vitamin D deficiency.
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Your body plays a role in skin cancer. Some folks are more at-risk for skin cancer than others. If your family has a history of skin cancer, you should probably be more concerned about your sun exposure. Skin color also plays into your cancer risk, because melanin protects your skin from sun damage. That means that darker-skinned people are less predisposed to skin cancer. The skin color thing has a flip side, though. It’s harder to see moles or other early signs of skin cancer on darker skin, so it’s tougher to catch if skin cancer does occur.
Dr. Robert S. Stern, chair of the Department of Dermatology at Harvard-affiliated Beth Israel Deaconess Medical Center recommends a middle-of-the-road approach to sun exposure. Go with an SPF 15 sunscreen in summer, he says, and take extra precautions to protect yourself from the strongest sun at midday. That’s when you need to really cover up and slap on a hat, according to Stern.
Sun Exposure and Vitamin D
Another point that I made in the original article is that some doctors are even prescribing sun exposure to patients, especially dark-skinned patients. In the Nautilus article, Seigel talks to 29-year-old Australian Vandana Verma whose doctor prescribed daily sunshine along with supplements to help combat her low vitamin D levels.
Our bodies are able to produce vitamin D from sunlight, which is why it’s called the sunshine vitamin. The darker your skin, though, the less able your body to absorb vitamin D. Melanin actually slows vitamin D production, which means the darker your skin, the more sun you need.
This is the part where I would recommend talking to your doctor about how much sun exposure is healthy for you, but if you live in the U.S., your doctor is not likely to prescribe daily sun exposure. American doctors shy away from giving complexion-based skin health advice, because race is a particularly touchy subject here in the U.S. Doctors here just don’t want to talk about it.
In 2004 vitamin D researcher Michael Holick lost his job at Boston University Medical School because he recommended 5-10 minutes of direct sun per day in his book The UV Advantage. If you’re wary about holding back some on the sunscreen, that book looks like a good starting place.
How much sun you need depends on how strong the sun is and on your complexion. Areas closer to the equator, for example, get more direct sunlight, which means you’re exposed to stronger UV rays in a shorter period of time. There is also more UV radiation during summer months versus winter. If you’re a natural blond or redhead with very pale skin, you might need only a few minutes of sun per day, where someone with an olive complexion or darker skin may need more.
Sun Exposure: Finding a Balance
M. Nathaniel Mead published a 2008 piece in the National Institutes of Health publication Environmental Health Perspectives that dives deeply into the science of sun exposure, its history, and its evolution. It’s a fascinating read, and in it he suggests that we need to create a “balanced message” on sun exposure.
Mead’s article cites the SunSmart program as an example of this middle-ground approach, echoing the advice to use sunscreen when the UV index is above a three.
If you’re in Australia, you can use the SunSmart Vitamin D tracker tool to see how long you should be out. You choose your region and skin type, then enter how long you have spent in the sun so far today. It tells you how much sun exposure you need to hit your vitamin D targets or whether it’s time to put on some sunscreen. Here in the U.S. you can use the EPA Sunwise tool to search by zip code or city name. I also found a handy site called UV Awareness that gives detailed UV levels for any city in the world.