Skin Cancer vs. Vitamin D
“I remember back in the old days, when bacon, eggs, and sunshine were good for you.”
--Author’s grandfather, Warren Swenson
Is sunshine good for you? Much like bacon and eggs, it depends who you ask. With the paleo diet books touting the virtues of bacon and eggs camped out on the best-seller lists for months at a time, a segment of society has turned back to these foods, seeing them as virtues, not vices.
The same could be said for good old-fashioned sunshine. Was grandpa right after all?
AMA vs. the traditionalists
As our savvy readers are no doubt aware, whenever the AMA takes a stand on one side of an issue, there’s a PhD, a paleo, a naturopath, or a nutritionist who will take the opposite position—and solar-powered UV radiation is no exception.
The AMA’s stance on this would seem to be pretty self-evident and has a ring of truth to it: stay out of the sun, because UV radiation causes skin cancer. Wear sunscreen, wear UPF clothing, floppy hats, and sunglasses, and you’re in for a melanoma-free life.
The other side—I will call them the traditionalists, represented in this feature by William B. Grant, PhD, of SUNARC, the Sunlight, Nutrition and Health Research Center—would argue that UV radiation on your bare, unsunblocked skin is the way that the body synthesizes vitamin D and has been for millennia. It’s a natural process. Americans as a whole are deficient in vitamin D, and studies have shown that being vitamin D-deficient leads to an increased risk of 15 different cancers as well as cardiovascular disease, dementia, diabetes, infectious diseases, and multiple sclerosis.
Part of the hubbub can be traced back to the varying recommendations for vitamin D in the blood, measured via the 25(OH)D blood test. WebMD recommends levels of 20 to 50 ng/ml, which is a very wide range. Less than 12 is considered vitamin-D deficient.
Studies indicate that optimal levels of vitamin D are above 40 ng/ml, but the most recent cross-sectional study showed levels of 26 ng/ml for white Americans, 21 for Hispanics, and 16 for African-Americans. “These values were down a few ng/ml from the 1990s,” says Dr. Grant. “The reasons could include the rising prevalence of obesity [fat cells extract vitamin D from the bloodstream], spending more time indoors behind computers, and fear of the sun leading to increased use of sunscreen, covering clothes, and general avoidance of the sun.”
So we’re a little short on vitamin D: what’s the big deal? In Grant’s paper “In Defense of the Sun” published in 2009 in the journal Dermato-Endocrinology he runs a thought experiment: what if we got enough sun exposure to raise our 25(OH)D levels to a robust 45 ng/ml?
“I estimated that the ratio of deaths from all causes to deaths from melanoma ranged from 2.8 for males and 4.2 for females in the 25 to 29 year range rising to 28 for males and 52 for females at the highest age range,” Grant said during our interview. So, for every additional melanoma death, 4.2 female lives would be saved in the 25 to 29 range, and 52 female lives would be saved in the highest age range.
“Melanoma is expected to account for 6,280 male deaths and 3,200 female deaths in 2013 while total cancer deaths in 2013 are estimated at 307,000 for males and 273,000 for females. There are many types of disease linked to vitamin D deficiency including cardiovascular disease, dementia, diabetes, infectious diseases, multiple sclerosis, and so on. Thus, basing any public health policy on avoiding risk of melanoma without considering the ‘unintended consequences’ is like the tail wagging the dog,” he says.
In addition to the diseases mentioned, numerous studies have shown that vitamin D plays a preventative role in 15 different types of cancers, including melanoma. (You’ve got to appreciate the irony there.) And, indeed, if you look at the incidence of breast cancer, colon cancer, ovarian cancer, and multiple sclerosis, they are lower in the South, and markedly higher in the North where we have less access to UVB each year.
Skin cancer risks and guidelines
I also interviewed Melanie Palm, MD, MBA, a young board-certified dermatologist who owns a well-regarded practice, Art of Skin, MD, in Solona Beach, CA (artofskinmd.com).
From 1970 to 2009, incidence of melanoma has risen 800 percent in young women, and 400 percent in young men—not what we’d expect during a time when sunscreen and stay-out-of-the-sun were the recommendations “Most of the increase is likely due to reporting bias,” said Dr. Palm. “We as a society have become more attuned to changing moles and melanoma. Additionally, dermatologists such as myself are finding and diagnosing melanoma, often at a very early stage, leading to an increased rate of diagnosis. This increased reporting likely is the most compelling reason for the increase in young adults affected by melanoma.”
And the dangers of skin cancers are certainly very real, especially in sun-kissed Southern California where Palm practices. Skin cancer comes in three varieties—melanoma, basal cell carcinoma, and squamous cell carcinoma—with carcinomas being the most common by far, and melanoma being the most serious and aggressive.
With skin cancer the rate of spread (or metastasis) is what really determines the danger.
“Melanoma cells, unlike other skin [cells], can rapidly spread from the top layer of our skin, called the epidermis, diving into the second layer, the dermis,” Dr. Palm said. “This ability to grow vertically allows access to lymph nodes and blood vessels that can transport melanoma cells to other tissues and organs. Melanoma cells misbehave, meaning they can grow and multiply, even outside their originating skin environment. This makes melanoma extremely dangerous and aggressive. It is still perplexing to scientists and physicians, and melanoma research is an intensive area of cancer study.”
As much as the AMA and the traditionalists may quibble over the role of sunlight in vitamin D synthesis, everyone says too much sunlight is a bad thing. Sunburns are bad for you, and are a key risk factor in skin cancer—period.
The key to surviving skin cancer is to catch it early. Dr. Palm advises her patients to use the ABCDE method when on the lookout for changing moles or melanoma. “Looking for Asymmetry, Border changes, Color changes, [large] Diameter moles, and Evolving lesions are important to identifying suspicious moles and even melanoma…the ‘E’ for ‘Evolution’ is the most important—any spot that is new or changing should deserve a proper evaluation by a board-certified dermatologist.”
The treatment for skin cancer is typically swift and decisive. “In the vast majority of cases, surgical excision is the standard of care for removing skin cancers,” Dr. Palm says. For melanoma, the thickness of it is the most important prognostic factor. Thin melanomas and melanomas that have not broken through the epidermis can have a nearly 100-percent cure rate when surgically removed.
Sunscreen: the pros and cons
The notion of pros and cons related to sunscreen will probably seem absurd to many. (It keeps you from getting skin cancer—where’s the downside?) Generally speaking, the correct sunscreen used properly must be seen as a good thing. The downsides to sunscreen are that some contain chemicals that have no business being on your skin, and many don’t block UVA radiation, giving wearers a false sense of security. UVB radiation is the one that prompts vitamin D synthesis, but it is also the one that causes sunburns if you get too much of it. UVA, on the other hand, has no useful health effects. UVA rays penetrate deeper into the skin and can cause free radical damage and oxidation.
So, if you’re using a cheap sunscreen with a lot of nasty chemicals, you might be staying out too long (it’s blocking the UVB and thus you’re not getting burned) and getting an overdose of UVA, missing out on making the all-important vitamin D, and taking in all those toxins from the sunscreen. Good for you? Not so much.
If you’re going to use a sunscreen, opt for one with broad spectrum (UVA +UVB) that has natural ingredients and is over SPF 30. Steer clear of oxybenzone, retinyl palmitate, and other hormone-disrupting synthetic chemicals. (For safe sunscreen recommendations see our Natural Radiance column in the April issue.)
The traditionalists/anti-sunscreen contingent argue that your skin has a built-in warning mechanism to tell you when you’re overdoing it. Listen to your body and seek shade or cover up accordingly. Of course, there are times when we must be in the sun for long periods and a broad-spectrum sunscreen with healthy ingredients is prudent in that case.
The role of diet in skin cancer
A few studies in the last 10 years have shown that a diet rich in vitamin D, antioxidants, carotenoids (α-carotene, β-carotene, cryptoxanthin, lutein, and lycopene) significantly reduced the risk of melanoma.
One study called “A protective effect of the Mediterranean diet for cutaneous melanoma” published in the International Journal of Epidemiology, noted that the sunny Mediterranean countries only had three to 11 cases of melanoma annually per 100,000 people, whereas Scandinavian countries had nine to 22, the US had 20, and Australia had 50. How to explain it?
The study summarizes their findings this way, “After a careful control for individual characteristics and sun exposure, the results of our study show that the Mediterranean dietary profile—characterized by regular use of fresh herbs, high intake of citrus fruits, carrots, cruciferous and dark green vegetables and high consumption of fish rich in n-3 [omega-3] fatty acids and shellfish—give protection against cutaneous melanoma, decreasing by about half the risk of cutaneous melanoma.”
Word to the wise—eating well affects everything, even skin cancer.
How to make sure you’re getting enough vitamin D
The real point of contention here between the AMA and the traditionalists hinges on the merits of having abundant vitamin D vs. the dangers of overdoing it in the sun.
The alternate approach here would be supplementation. There’s universal agreement that supplementation is a fine way to get your vitamin D, but as Dr. Grant points out “It takes 1,000 to 4,000 IUs a day of vitamin D3 to reach 30-40 ng/ml.”
That’s a lot. If you’re taking a multivitamin, you may get around 1,000, and diet won’t be a big help in this regard. Three ounces of salmon has roughly 800 IU (which is great), but a cup of vitamin D-fortified milk is only good for about 100, and a serving of “fortified breakfast cereal” will only net you about 40, so don’t bother with it. (If you want to know your vitamin D level, which I’d highly recommend, any physician can order it, or you can do it through grassrootshealth.net or vitamindcouncil.org.)
If you want to get vitamin D through sun exposure, you really don’t need that much. Dr. Grant advises anywhere from five to 30 minutes of direct exposure to midday sun (you’ll need a fair amount of bare skin here), and get out of the sun before you start to turn pink. Such a short exposure can net you 10,000 IUs, plus it’s fun! (It’s worth noting that UVB rays generally aren’t available early in the morning or later in the evening, and those of us in the North get no UVB from October to April.)
Dr. Palm, of course, would disagree strenuously, and she has a point—if you are going to supplement adequately with vitamin D, you don’t need to get it from the sun. And if you have a family history of melanoma or you are fair skinned or have red hair, you really should be very conservative and slather on the broad spectrum and wear floppy hats and sunglasses.
And, human nature being what it is, supplementation only works if you take it. A recent study published in Clinical and Experimental Dermatology titled “The Vitamin D Status of Australian Dermatologists” reads “This study found that vitamin D insufﬁciency was common among dermatologists in temperate Australia during the winter of 2006. In total, 83 percent of those tested had serum 25(OH)D levels < 50 nmol ⁄ l [less than 20 ng/ml], which is considered to be the minimum needed for good health.” Dermatologists, of all people, should know the importance of vitamin D, and Australia provides ample UVB rays all year-round. Avoidance was not doing these dermatologists any favors.
Good intentions do not adequate levels of vitamin D make. If you’re going to skip the UVB, get your 4,000 IUs of D3.
Summing it up
As always, information allows us to make wise choices. Those who are fair skinned should heed the AMA’s guidelines as their risk of melanoma is much greater—and, if they’re vitamin D deficient like most of us, they should supplement with vitamin D. Those of you who aren’t pasty British types can get out in the sun and get some vitamin D the way grandpa used to—just don’t overdo it.