The US Surgeon General recently came out with a warning on skin cancer,1claiming that the sun is dangerous and that you need to stay away out of it.
Dr. John Cannell, founder of the Vitamin D Council, has dedicated a large part of his professional career to the study of vitamin D and its health benefits, and he has a warning of his own to those who take this narrow-minded advice to heart.
It’s worth noting that the acting Surgeon General, Boris Lushniak, is a dermatologist. And of all the medical specialties out there, dermatologists are clearly the most biased against sun exposure, and as a result, against vitamin D.
This isn’t surprising, since they primarily see the ill effects of sun overexposure. But in taking an overly narrow view, the advice to avoid sun exposure as much as possible can have equally if not greater adverse health effects.
The Connection Between Sun Exposure and Skin Cancer
Unquestionably, UV radiation can be dangerous; it can increase your risk for certain skin cancers such as squamous cell, basal cell, and melanoma. But there are significant differences even between these cancers, and appropriate sun exposure may actually be more beneficial than detrimental in some cases. Dr. Cannell explains:
“Squamous cell carcinoma is clearly associated with chronic sun exposure. It is more common on the face, the hands, and the scalp.
It is related to radiation burden over your lifetime, and together with basal cell carcinoma, which is sort of intermediate, it accounts for approximately 1,500 deaths a year in the United States...
Basal cell is sort of intermediate. There are studies showing that it is associated with chronic sun exposure, and there are studies showing that it’s not associated with chronic sun exposure.
And then there’s melanoma, which is responsible for almost 9,000 deaths a year and is the deadly skin cancer that is feared. The relationship that melanoma has with the sun is quite complicated.
It is clearly associated with sunburn, especially sunburns when you’re young (that’s incontrovertible) or sunburns in a sun tanning bed.”
However, there are at least two studies showing that melanoma is more common in indoor workers than outdoor workers. And the most likely places for melanoma to appear are actually NOT the face and the hands like squamous cell carcinoma, but rather the lower back and the upper leg—areas that are usually not chronically sun-exposed.
According to Dr. Cannell, there’s a vocal minority in the dermatological community that thinks the emphasis dermatologists have on avoiding sun exposure is wrong, because while sunburn is a risk factor, chronic sun exposure is not.
“A number of studies show that chronic sun exposure is related to melanoma, but they don’t separate out the sunburns, which is very hard to do because you have to do that by memory,” Dr. Cannell says.
Two Decades-Long Study Finds Sun Avoidance Doubles Risk of Death
Dr. Cannell notes a recent study2 done in Sweden, which followed nearly 30,000 middle-aged to older women for up to 20 years. The average follow-up was 15 years.
At the outset, they asked a number of questions about sun exposure, such as: Do you sunbathe? Do you take vacations in sunny areas in the winter? Do you garden with short sleeves and shorts? And, do you use sunbeds?
What they found, and this appears to be the only study of this kind, is that the women who avoided the sun were twice as likely to die over the course of the study. The researchers attributed this finding to a vitamin D mechanism.
What this study actually shows is that chronic sun exposure appears to be associated with less mortality. It’s also the first study to show that women who use tanning beds live longer than those who don’t.
This is in direct conflict to what almost every dermatologist will say, including the Surgeon General. It’s unfortunate, but the danger of almost any specialist is that they don’t take the broader perspective.
What the Surgeon General and almost every other dermatologist fail to take into account is the overall mortality, which is referenced in this recent study.
In addition to this study, dozens of others document the benefits of appropriate sun exposure. This includes a reduced risk of about 16 different cancers of Dr. Garland’s studies suggest this reduction is close to 50 percent.
So many hundreds of thousands of people are put at risk from other cancers as opposed to 10,000 people who are dying from skin cancer caused by sunburn. It’s really a matter of making an educated risk-benefit analysis.
“When you do a risk-benefit analysis and you look at all the data we have, the risk in my opinion appears to be in those who avoid the sun,” Dr. Cannell says.
“Now, if you avoid the sun, your risk for non-melanoma skin cancer goes down. That’s clear. But if you look at studies of either latitude or of 25-hydroxyvitamin D levels in relation to cancer, you find this inverse relationship: the higher the vitamin D level, the lower the internal cancer rate.”
Dr. William Grant of Sunlight, Nutrition, and Health Research Center (SUNARC) estimates that if everyone in the United States had a vitamin D level of 40 nanograms per milliliter (ng/ml), it would save approximately 150,000 lives a year.3
That’s 100 times the rate of squamous cell cancers, which are the only ones that are definitively linked to UV exposure. In Canada alone, it is estimated that 37,000 lives a year are lost due to vitamin D deficiency.4 Also, use of sunscreen has risen in the last 30 years, so if dermatologists were correct, there should be a decrease in stage 1 melanoma. But there’s not. As sunscreen use increased, stage 1 melanoma diagnosis increased...
“It’s thought that by blocking out UVB, patients are able to stay out in the sun longer than they would have otherwise and expose themselves to the more dangerous, or at least potentially dangerous, UVA radiation that’s in the sunshine,” Dr. Cannell says. “What we recommend is what’s called safe, sensible sun exposures. The Australian Cancer Council now recommends the same thing. I think in England there’s now a change in their recommendation from strict sun avoidance to some safe, sensible sun exposure. There are some movements in large organizations to realize that safe, sensible sun exposure is a healthy thing.”
How Much Sun Exposure Is Sensible?
On its website, Cancer Research UK reports that “by enjoying the sun safely and avoiding sunburn, people can reduce their risk of skin cancer and enjoy the beneficial effects of the sun.” Cancer Research UK’s sun advice is endorsed by the British Association of Dermatologists, Cancer Research UK, Diabetes UK, the Multiple Sclerosis Society, the National Heart Forum, the National Osteoporosis Society, and the Primary Care Dermatology Society. The UK National Health Service5 also recommends sensible, individualized sun exposure to help optimize vitamin D.
It’s important to recognize is how quickly sunlight can make vitamin D in the skin. You don’t need to be outside for hours on end. But you do need more than just a few minutes of sun on your face and arms. According to Dr. Cannell, sunbathing at solar noon in the summer, at most latitudes in the United States you will make between 5,000-10,000 international units (IUs) of vitamin D within 30 minutes.
“You can ask yourself why nature would evolve a mechanism that made so much vitamin D so quickly,” Dr. Cannell says. “When I thought about that question, the only answer I could come up with is nature did it for a good reason. The organism needs vitamin D, so the system in the skin evolved to make it very quickly upon exposure to sunlight.
We recommend full-body sun exposure for up to anywhere from a few minutes to 30 minutes every day. On those days when you cannot get a full-body sun exposure, we recommend a vitamin D supplement or sensible exposure in a low-pressure UVB bed.”
If you’re getting regular sun exposure, I think the need for an oral supplement is really minimal to non-existent. When you swallow a pill, there’s no self-regulating ability. Your body doesn’t have an ability to selectively limit its absorption. But your skin has the ability to control how much vitamin D is being produced based on how much is in your blood.
I personally have not taken oral vitamin D for five years and my level runs from 50-70 g/ml. Lifeguards, roofers, and gardeners who work with their shirt off, all tend to have levels between 40 and 80 ng/ml in the summer. This also brings up an interesting question about the difference between normal and natural. Normal vitamin D levels are an average of what indoor workers have in both winter and summer. Natural are levels of a population with widespread sun exposure. The latter is going to be closer to ideal, or optimal.