I wasn’t totally aware of the power of the sun until I was 24 years old. That was the year I shaved my comb-over and committed myself to full Michael Jordan-level baldness. You don’t realize how much sun your hair keeps off your scalp until you’re bald. It gave me an appreciation for what ants feel when they see a kid with a magnifying glass.
A few years after I shaved my head, I went to the doctor for a routine checkup. She warned me, “You should not leave the house without sunscreen, even if you are going to your car. You’ll get radiated.” She then made a zapping sound in case I missed her subtle use of the word "radiated." I heeded her advice, and I wore a hat and slathered sunscreen on my arms every day.
For a while.
Then I stopped.
I stopped when I started reading about the health benefits of vitamin D. I got interested in health in my early 30s, which apparently, a lot of guys do. I learned that vitamins were something I should put inside my body intentionally. Vitamin D is an important one, and the most efficient way to get vitamin D, I learned, was from the sun.
So now I only use sunscreen when I am outside for long periods of time. Have I made the right choice? Is this healthy? Am I getting enough vitamin D?
Or do I run the risk of exploding while walking to my car?
It’s Not You, Sun, It’s Me
Human beings evolved to adapt to their environments, and they did so in the sun. As a result, our bodies grew acclimated to being outside. So, how come some people get skin cancer and some are vitamin D deficient?
Penn State anthropology professor Nina Jablonski says it’s because human beings are globally mobile -- and the adaptation mentioned above, was specific to our true original environments. The farther we move from our ancestral homelands, the more at risk we are of losing the adaptations that once gave us an evolutionary advantage.
About two million years ago, melanin evolved in humans to regulate the body's reaction to ultraviolet rays. Pigment allowed enough ultraviolet radiation in the body to produce vitamin D, and humans became solar powered. Melanin also protected the skin from intense UV radiation. When humans migrated from the equator to places like England and Russia, they lost pigmentation.
Enter the wheel, the gasoline engine and the jet plane. Now humans of varying pigmentations live and vacation all over the globe. They also mostly live in cities, where their exposure to the sun is limited, and their ability to make vitamin D is reduced. Jablonski’s research points out that health problems compound when people do not receive enough sun or when there is a mismatch between their pigmentation and ultraviolet radiation.
If your skin is dark, Jablonski says, you have more melanin pigment than if your skin is light. This means that some of your ancestors evolved in a sunny place with high levels of UVR and that you have some built-in natural sunscreen. If your skin is light, this means some of your ancestors evolved under lower levels of UVR and that your skin is more sensitive to strong sunlight. By observing your own skin, you can learn a lot about the solar conditions under which your ancestors evolved.
Jablonski urges people to consider their geography and lifestyle when making choices about their health. Is there strong year-round sunshine? Is more time spent outdoors or indoors?
“By assessing these simple parameters of your own life, you can figure out if your skin color is matched well to your location and lifestyle or if there is some level of mismatch,” Jablonski explains. “Most people these days must compensate in some way for the mismatch between their skin and their location and/or lifestyle.”
For people with darker skin who live in places with weak sunlight and who work indoors, this means that they should compensate for a lack of vitamin D production by making sure they get adequate D through supplements, says Jablonski.
Diet alone isn’t an option when it comes to getting enough vitamin D.
For people with lighter skin living in places with strong sunlight, compensating for a mismatch between pigmentation and location means wearing sunscreen, clothing and other forms of sun protection to protect against the harmful effects of UVR.
“Like the other inhabitants of Earth, we evolved under the sun, and we are basically well adapted to sunshine,” says Jablonski. “The problems we have with the sun today that result in our getting too little or too much sunlight are of our own making and are mostly due to modern lifestyles, and to the fact that we live so much longer than most of our ancestors. When we understand and appreciate this, we can make appropriate compensation through our behavior and culture.”
Fear the Sun
Dr. Len Lichtenfeld, deputy chief medical officer for the American Cancer Society, has skin cancer. Lichtenfeld was attending a meeting about Medicare fee schedules—oh, the thrilling life of a modern healer — when one of his colleagues tapped him on the shoulder and ushered him outside. A group of five dermatologists who were at the meeting staged an intervention and told him that a nodule on his face had to be removed immediately. They scheduled the appointment, and a dermatologist removed a basal cell. Lichtenfeld appeared a week later before Congress to raise awareness for skin cancer with a bandage on his face.
Like Lichtenfeld, more than 3.5 million Americans are diagnosed annually with skin cancer. Skin cancer makes up roughly half of all cancers diagnosed in the country. If that number seems high, remember that skin is the largest organ in the human body, and it performs a wide variety of important functions, which include, for example, keeping your guts from falling out all over the floor.
The vast majority of the 3.5 million skin cancer diagnoses are non-lethal basal and squamous cell skin cancer. Melanoma is the most serious form of skin cancer. It accounts for an estimated 76,690 new cases per year and is the cause of an estimated 9,480 deaths annually.
Lichtenfeld said the science linking sun exposure to skin cancer is solid, in spite of what some dermatologists have said to the contrary. One of the reasons the sun cancer link bubbles up as an issue is that it’s possible to get lethal skin cancer without being exposed to the sun. Melanomas can be caused by hereditary conditions or other conditions such as medication.
As for vitamin D, Lichtenfeld believes it is best received through supplements.
“Most experts understand that being outdoors is part of a healthy lifestyle,” he said. “What people need to know is that they should follow sun-safe behaviors when they go outdoors, particularly when they go to the beach. What they don’t need to do is seek the sun as a source of vitamin D.
“Supplements are inexpensive and available over the counter. It’s a much safer way of getting vitamin D than seeking the sun.”
I asked the doctor if it was realistic to expect the entire country to buy supplements while also consistently engaging in sun-safe behavior.
“They should be (doing this),” Lichtenfeld said. “Expert bodies believe that vitamin D replacement should be part of our everyday habits, and it’s a lot safer and a lot less expensive to take vitamin D than it is to deal with the epidemic of skin cancer we have in this country.”
What’s wrong, I asked, with 20 minutes of sun on skin?
“Twenty minutes of sun in the middle of the winter in Portland, Maine, is a lot different than 20 minutes of sun in the middle of the summer in Phoenix, Arizona,” Lichtenfeld said. “Different people have different skin types, and the effects of sun on the skin are cumulative over time. You have someone with fair skin, and they may burn or get cumulative damage over time. Twenty minutes a day is highly variable. It’s variable by individual. It’s variable by location.”
Lichtenfeld encourages that we all “Slip-Slop-Slap.” Slip on a shirt. Slop on 30+ SPF sunscreen. Slap on a hat.
“A tan is a sign of skin damage,” he says. “It does protect, yes, but it protects you from further damage. It’s a damage response, not a healthy response.”
Our Friend, The Sun
Yet the sun confers many health benefits. A 2008 report published by Nathaniel M. Mead says that excessive UVR exposure accounts for only .1 percent of the total global burden of disease, according to the 2006 World Health Organization report “The Global Burden of Disease Due to Ultraviolet Radiation.”
Mead’s study notes that many diseases linked to excessive UVR exposure are relatively benign — apart from malignant melanoma — and occur in older age groups because of the lag between exposure and manifestation or the requirement of cumulative exposure. Skin cancer is common, but not often fatal. The same 2006 WHO report points out that a larger annual disease burden might result from inadequate UVR exposure.
Living at higher latitudes — where there is less UV exposure — has been shown to increase the risk of dying from Hodgkin’s lymphoma, breast, ovarian, colon, pancreatic, prostate and other cancers. Low levels of vitamin D also have been linked to multiple sclerosis, type 1 diabetes, metabolic syndrome, hypertension, rheumatoid arthritis, asthma and infectious diseases.
You can see how this poses a conundrum for the medical community. It’s possible that people are staying out of the sun to avoid skin cancer, which is largely non-fatal, and are putting themselves at risk of much more fatal cancers and diseases as a result.
“If you do a risk-benefit analysis, sunlight increases the risk of skin cancer but reduces the risk of cancers that kill Americans,” said Dr. John Cannell, executive director of the Vitamin D Council. “Sunlight is very beneficial.”
Sunlight also lends benefits beyond vitamin D production. It has been shown to aid sleep, curb depression and possibly more. Researchers at the University of Edinburgh recently found that sun exposure may help reduce blood pressure. It’s a small study, but if its results hold up over time, it could lead more experts to conclude that a reduction in blood pressure is more beneficial to the population than the danger of non-melanoma skin cancer.
Sun & Supplements
I did not know this before I interviewed him, but I follow a plan similar to what Cannell recommends, which is a combination of safe sun and supplements. So far it’s worked for me.
When the whole body is exposed to direct sun for brief periods, it produces vitamin D quickly, about 1,000 units per minute. The Vitamin D Council recommends 5,000 to 10,000 units per day. (You can read more about its sun recommendations and the recommendations from the American Cancer Society in the links below this story.)
Americans who live south of Atlanta are able to take advantage of good direct sun year-round. Above Atlanta, during what Cannell calls Vitamin D Winter, Americans should take vitamin D supplements because there is not enough sun or vitamin D in the diet to meet the body’s needs. I encourage you to check in with you doctor and see what they recommend for you.
Remember, everyone’s body is different, and your body is also affected by where you live geographically. So be smart. And, if you read a story one day about a guy who exploded in his driveway — my bad.
- Modern life may cause sun exposure, skin pigmentation mismatch
- Cancer Facts and Figures 2013
- Benefits of Sunlight: A Bright Spot for Human Health
- Study: Benefits of sun exposure may outweigh risks
- How do I get the vitamin D my body needs?
- Be Safe in the Sun
- Solar ultraviolet radiation: Global burden of disease from solar ultraviolet radiation