Skin Cancer and Sun:

Vitamin D, Skin Cancer, the Sun, and Dermatologists

By Dr. Ralph Moss
from Newsletter

Science should by definition be open-minded. As the celebrated eighteenth century German poet and philosopher Goethe said, "As soon as anyone belongs to a narrow creed in science, every unprejudiced and true perception is gone." This week [late May, 2004] I begin a two-part series on an important event that has recently been in the news: the firing of a Boston University professor who has written a book that puts forward ideas that run counter to current medical doctrine.

Vitamin D and Cancer: A Dermatologist's Dilemma - Part 1

A Boston professor of dermatology has been asked to resign because he advocates moderate exposure to sunlight. Michael F. Holick, MD, PhD, a professor at Boston University, was asked to resign in April from BU's Department of Dermatology because of a book he wrote, in which he describes the importance of sunlight in boosting vitamin D levels. He was also severely criticized for his ties to the indoor tanning industry.

Department chair Barbara Gilchrest, MD, told the Boston Globe that the book "is an embarrassment for this institution and an embarrassment for him." As demanded, Holick resigned his post, but continues to teach and to direct the medical center's Vitamin D, Skin, and Bone Research Laboratory, without a cut in pay.

Holick is a talented, experienced and highly respected researcher. He is a professor of medicine and physiology, and formerly of dermatology, at Boston University School of Medicine, and (until 2000) chief of endocrinology, metabolism and nutrition. Since 1987 he has also been the program director of the University's General Clinical Research Center.

Department chair Gilchrest's disapproval of Holick stems from the fact that his statements, superficially at least, seem to be at odds with the medical profession's consensus on the damaging effects of sunlight. Dermatologists have been warning the public for years that sunlight, and specifically ultraviolet A (UVA) and ultraviolet B (UVB), is implicated in the causation of melanoma, as well as other less deadly forms of skin cancer.

But the causes of melanoma are still far from established, and there remain many unanswered questions about the exact relationship of sunlight exposure to the development of skin cancers. Exactly how much ultraviolet light constitutes a safe level of exposure is a legitimate topic for scientific debate. For example, according to the American Cancer Society, "We do not yet know exactly what causes melanoma …but we do know that certain risk factors are linked to the disease….Some risk factors, such as smoking, can be controlled. Others, like a person's age or family history, can't be changed. But having a risk factor, or even several, doesn't mean that a person will get the disease" (ACS 2004).

As to sunlight, the ACS says this: "The best way to lower the risk of melanoma is to avoid too much exposure to the sun and other sources of UV light…. Avoid being outdoors in sunlight too long, especially in the middle of the day when UV light is most intense…."

But this view is not universally held. William B. Grant, Ph.D., who heads the Sunlight, Nutrition and Health Research Center (SUNARC) in San Francisco strongly disputes it. "This is not particularly good advice," he told this newsletter. "There are several papers indicating that occupational exposure to sunlight reduces the risk of melanoma (Kennedy 2003). "It is having fair skin, a high-fat, low fruit and vegetable diet, sunburning, etc., that are more linked to melanoma than total UV exposure."

Reasonable people can certainly differ over this complex question. Such vague terms as "too long" or "too much exposure" leave much room for disagreement. In science, intellectual rigidity is never warranted, especially when it rests on fundamental confusion about the actual causes of a potentially fatal human disease.

Despite scientific uncertainty, the attack on Dr. Holick has taken on a quasi-moralistic tone. Some dermatologists, possibly frustrated at the failure of most of their treatments to reverse advanced melanoma, now regard sun exposure without sunblock as analogous to promiscuous sex without condoms. But ultraviolet sunlight (particularly UVB) is not always and absolutely bad for our health. It has essential functions, too. In particular, it enables our skin to manufacture vitamin D: without sufficient exposure to sunlight we run the risk of developing the deficiency disease rickets.

Vitamin D and Internal Cancers

The benefits of sunlight and vitamin D for the development of healthy bones have long been known: a Nobel Prize was awarded for discoveries relating to the importance of vitamin D as early as

But what has only fairly recently been discovered is that, in addition to its role in bone metabolism, vitamin D may also help prevent a variety of cancers. I wrote about this in my book Cancer Therapy in 1992. I quoted the work of San Diego scientists Drs. Cedric and Frank Garland, who argued that colon cancer could be prevented by sunlight. The Garlands went further, however, showing that "brief, regular exposure to sunlight was probably beneficial in preventing melanoma, while either too little or too much exposure was potentially harmful" (Moss 1992, citing Garland

The research on the subject of vitamin D and cancer is now voluminous, with over 3,500 PubMed articles on the topic. The US National Institutes of Health has stated that "laboratory, animal, and epidemiologic evidence suggest that vitamin D may be protective against some cancers. Some dietary surveys have associated increased intake of dairy foods with decreased incidence of colon cancer. Another dietary survey associated a higher calcium and vitamin D intake with a lower incidence of colon cancer" (NIH 2004). One randomized trial, published last December, showed that people who had high vitamin D levels benefitted from calcium supplementation: the incidence of premalignant adenomas of the colon was reduced by 29 percent in those who had optimal amounts of both nutrients (Grau 2003).

Vitamin D (and indirectly, therefore, sunlight) might also convey protection against prostate cancer. It is certainly true that more full-scale clinical trials need to be done to test this hypothesis. (PubMed lists 29 such trial articles.) But people are exposed to sunlight every time they step outdoors; the public needs and deserves preliminary recommendations from those with the greatest knowledge.

Dr. Holick's "crime" is that he has provided an answer that is at variance with the positions of the professional dermatology associations. Yet he is well positioned to offer an opinion, as he himself is in the forefront of this research. He is the author of over 200 PubMed articles on the topic of vitamin D, the first of which appeared in 1970. The latest, published this March, suggests the scope and importance of his research: "Vitamin D: importance in the prevention of cancers, type 1 diabetes, heart disease, and osteoporosis" (Holick 2004). By contrast, Dr. Gilchrest, although herself well published in dermatology, has only authored two PubMed papers on vitamin D, one of which she co-authored with Dr. Holick.

It is hard to believe that a policy dispute of this sort would warrant such a gross violation of academic freedom and intellectual rights. We do indeed live in parlous times when doctors are removed from high positions for offering carefully reasoned and well intended advice to the general public on preventing cancer!

Mysteries of Sunlight

There is much about sunlight's biological effects that is not known and no one would argue that the case for increasing ultraviolet exposure has yet been conclusively proved. But neither is it firmly established that blocking sunlight is entirely beneficial. In fact, the value of physical or chemical sunscreens is itself in dispute.

In February 1998, an epidemiologist at Memorial Sloan-Kettering Cancer Center in New York, Dr. Marianne Berwick, presented a careful analysis of sunscreen use and skin cancer at the annual meeting of the American Association for the Advancement of Science (AAAS). She concluded that sunscreens may not actually protect against skin cancers such as melanoma. In her own words: "We don't really know whether sunscreens prevent skin cancer." Berwick first looked at four studies of squamous cell cancer, a skin cancer that is destructive but not frequently lethal. Two of the studies concluded that sunscreen protected against a precancerous skin condition while two others reported that sunscreen did not shield people from this condition.

She then analyzed two studies of basal cell carcinoma, another generally non-lethal skin cancer. Those two studies found that people who used sunscreen were actually more likely to develop basal cell cancer than people who did not.

Berwick then analyzed ten studies of melanoma, the most deadly form of skin cancer. Melanoma often starts in or near moles on the skin. In five of the ten melanoma studies, people who used sunscreen were also more likely than nonusers to develop melanoma. In three of the studies, there was no association between sunscreen use and melanoma. In the final two studies, people who used sunscreen seemed to be protected (Berwick 1998).

More recently, L.K. Dennis of the University of Iowa reviewed the topic in the Annals of Internal Medicine. Again, he found that sunblocks offered no protection: "No association was seen between melanoma and sunscreen use," he and his colleagues wrote (Dennis 2003).

Dr. Berwick's was a factual presentation. But the dermatology profession's response to her analysis was as unmeasured as its response to Dr. Holick. The American Academy of Dermatology promptly denounced the Memorial Sloan-Kettering researcher's conclusions. In March 1998 the Academy issued a press release calling her message "misleading and confusing."

Roger Ceilley, MD, a Des Moines dermatologist and a past president of the Academy, called Berwick "a numbers cruncher," not a doctor, according to an article in Science News. Incidentally, Dr. Ceilley, has only one PubMed article on the topic of melanoma, dating from 1980 (Elmerts 1980). Dr. Berwick—the Sloan-Kettering "numbers cruncher"—has 81 such publications.

"We're going to have millions more cases of skin cancer in the next decade" if people forgo sunscreen, Dr. Ceilley proclaimed (Fackelmann 1998).

Vitamin D and Cancer: A Dermatologist's Dilemma - Part 2

Last week I wrote about the firing of Boston University dermatologist, Michael F. Holick, MD, PhD. Dr. Holick was sacked for suggesting, in his book The UV Advantage, that people seek out a few minutes of unblocked sunlight a couple of times per week. The goal is to boost the skin's production of vitamin D, thereby reducing the risk of contracting various diseases, including cancer. The ancient grandmotherly advice to "get a little color in your face" may not be all wrong!

It is commonly believed that exposure to sunlight leads to skin cancer, including deadly melanoma. No one believes this more ardently than leaders of the dermatology profession. For example, a leading dermatologist, Roger Ceilley, MD, has proclaimed, "We're going to have millions more cases of skin cancer in the next decade" if people forgo sunscreen (Fackelmann 1998).

Yet the relationship may not be that simple. There is evidence that a moderate amount of unblocked sunlight is actually beneficial to most people, reducing the risk of many diseases – including, paradoxically, melanoma itself. For example, in often-cited research on US Navy personnel in San Diego, researchers from the University of California School of Medicine found that more melanoma occurred among desk workers than among sailors who worked outdoors (Garland 1990).

Over a ten-year period, 1974-1984, the researchers identified
176 cases of melanoma among active-duty white male Navy personnel. The risk of melanoma was then determined for occupations that were grouped into three categories of sunlight exposure: (1) indoor, (2) outdoor, or (3) indoor and outdoor.

Compared with the US civilian population, Navy personnel in indoor occupations had a higher age-adjusted incidence rate of melanoma (10.6 per 100,000). But persons who worked in occupations that required spending time both indoors and outdoors had the lowest rate.

Another intriguing finding was that incidence rates of melanoma were higher on the trunk of the body than on the more commonly sunlight-exposed head and arms. This alone calls into question the notion that exposure to sunlight equals increased rates of melanoma.

The UC San Diego researchers concluded that there was a protective role for brief, regular exposure to sunlight. They also pointed to laboratory studies showing that vitamin D suppresses the growth of malignant melanoma cells in tissue culture. They suggested that vitamin D could inhibit previously initiated melanomas from becoming clinically apparent (Garland

But ideas such as these have made some dermatologists very angry indeed. Boni E. Elewski, MD, current president of the American Academy of Dermatology, has argued that even a few minutes of sunlight exposure can be dangerous, and that people can get all the vitamin D they need through supplements. This is a strange recommendation indeed, since orthodox doctors usually urge the laity to shun food supplements. (Incidentally, I can find no published scientific papers by Dr. Elewski on the topic of vitamin D.)

Despite dermatologists' vehement opposition to the idea, it is not at all clear that small amounts of unblocked sun exposure could be a significant cause of melanoma. As even the Skin Cancer Foundation states, "Epidemiologic studies have suggested that intense intermittent exposure resulting in sunburn, especially in childhood, is most likely to lead to melanoma development." (Skin Cancer Foundation 2004) But full-blown intermittent sunburn is not at all the same thing as getting a bit of sun on a winter afternoon in the northern latitudes.

Of course too much of a good thing can be dangerous. But the essential point that Holick makes is that by moderately increasing our exposure to sunlight, we can probably decrease our risk of many forms of cancer, as well as diabetes, seasonal affective disorder (SAD), multiple sclerosis, and other illnesses. Interested readers should take a look at the maps of disease distribution and mortality at the website of the SUNARC Foundation of San Francisco at

What these maps clearly show is that, as a general rule, the death rates for breast, colon and ovarian cancer, as well as incidence rates for multiple sclerosis, decrease as one moves south. For example, the breast cancer death rate in the south is about half of what it is in the north and northeast. Dr. William B. Grant, founder of SUNARC, has published a paper in the journal Cancer, in which he argues that these differences are due to sunlight and vitamin D (Grant 2002).

If he is correct, then this is very good news indeed for the "worried well." Brief but regular sunlight exposure could turn out to be a healthful measure that is easy to implement, cost-free and accessible to almost all. And ironically, despite the fervent objections from photophobes in the medical profession, it might even decrease the risk of melanoma.

Growth of Intolerance

Yet the moral climate these days has become polluted by dogmatism, bigotry and petty-mindedness. Science is supposed to be an island of rationality in a sea of intolerance. Yet intolerance is rearing its ugly head here as well.

Astonishingly, advocating even a few minutes of exposure to Old Sol these days is enough to get you black balled by your profession, regardless of prior accomplishments. "Any group, organization, or individual that disseminates information encouraging exposure to UV radiation, whether natural or artificial, is doing a disservice to the public," Elewski menacingly told The Scientist ( Read that sentence over. This is what we've come to in America, circa 2004. One would have to go back to the McCarthy era or to the 1930s—when (to paraphrase the poet W.H. Auden) "intellectual disgrace stared from every human face"—to find an equivalent.

There is much in this current debate on sunlight that is reminiscent of the longstanding feud over dietary fat. First, Dr. Robert Atkins was excoriated by almost the entire medical profession as a fraud and a quack. Then there was a grudging admission that his diet may work sometimes, but for reasons other than those he postulated. Now, after the public in its millions has deserted the orthodox position on weight loss, the medical profession is running full tilt to catch up. Recently I awoke to the following headline: "Longest scientific study yet backs Atkins diet." Two clinical trials conducted at the Philadelphia VA hospital and at Duke University, published in the prestigious Annals of Internal Medicine, have found that subjects on the Atkins diet shed significant amounts of weight without harmful effects on blood fats and sugars (Coghlan 2004).

My purpose here is not to weigh the merits and demerits of the Atkins low-carb diet. Rather it is to point out that all too often science is ruled not so much by cool reason as by pride and prejudice. The reaction to Dr. Holick's research is a case in point.

Demonizing sunlight (and those who advocate moderate exposure) is a manifestation of dogma rather than science. Perhaps a certain narrowness of vision is an inevitable result of professional over-specialization. Dermatologists spend their days looking for melanoma, an insidious and deadly disease. After a while, they begin to see UV exposure (which is indisputably dangerous when carried to extremes) as the sole source of this evil. Dermatologists are not asked to worry about non-cutaneous forms of cancer, or about diabetes, seasonal affective disorder (SAD), or any of the other illnesses that may be prevented by judicious UV exposure. They just care about skin disease. As the old saying has it, ‘to the hammer, everything looks like a nail'.

A Question of Sponsorship

Much of the animus against Prof. Holick stems from his friendly relationship with the Indoor Tanning Association (ITA), a society that represents people working in that burgeoning industry. Holick is said to have unveiled his new book during a meeting of the ITA, which has also hired a publicist to promote it and has contributed $150,000 to his research.

While his association with the ITA may have been professionally unwise, Holick has denied that his research is influenced by any financial conflict. I have no reason to believe otherwise. It is unlikely that a distinguished and accomplished researcher would compromise his honesty for a few grants. One needs to look at the totality of the man's accomplishments. To me, these all add up to an honest lifelong search for the truth.

Besides, there is something hypocritical in this criticism of Dr. Holick. Of course, it would be better if all research could be independently funded, thereby eliminating the need for researchers to go cap in hand to those who have a vested interest in the outcome of their research. But it certainly seems ironic that leading dermatologists should rebuke Holick so roundly for his ties to the indoor tanning industry when in truth most medical research today is supported by interested parties of one kind or another. Imagine what would happen if all researchers with ties to the pharmaceutical industry were asked to resign. There would be hardly any top doctors left in America's medical schools and research laboratories. Are dermatologists willing to accept that funding of research from, say, the chemical sunscreen industry should also be prohibited? I haven't heard those sentiments expressed by those who are now harrumphing over Dr. Holick's connections to indoor tanning.

The Case of Dr. Healy

Are we in for a new round of medical McCarthyism? Dr. Holick's case is similar to that of another medical professor who was also recently fired for unorthodox views. Dr. David Healy was removed from his post by the University of Toronto's Centre for Addiction and Mental Health (CAMH), after he wrote a book that was highly critical of the pharmacological approach to mental illness (Kendall 2004).

He stated the following: "Scientific progress in psychiatry has been stalemated because Big Pharma's marketing efforts have overwhelmed the field." This powerful statement points to a far more serious and pervasive problem than Dr. Holick's grant from the tanning lobby.

Signs of Fairness

However, there are still a few encouraging signs of elementary fairness in American medicine. Some vitamin D experts have rallied to Holick's side and have agreed that he should not have been forced to resign. "If he was fired for his opinion, which is based on science, then it would appear to be a violation of the principles of academic freedom," said James Fleet, PhD, who studies nutrition and vitamin D at Purdue University. Whether small amounts of sunlight can boost vitamin D intake without raising the risk of cancer "is an issue worth debating," Fleet has said.

Similarly, Reinhold Vieth, PhD,of the University of Toronto, who has worked with vitamin D since 1974, said that the shunning of Dr. Holick represents a "narrow-minded" approach to health. "It's like a horse with blinkers, and the only thing they [the orthodox dermatologists, ed.] see is melanoma."

Dr. Holick's response has been rather mild-mannered. He has said that he was "disappointed" and "surprised" when asked to step down simply on account of the fact that his opinions differed from those of some of his colleagues. "If you don't follow that party line, then they'll make every effort to squelch everything you have to say," he said.

This year another 1.3 million Americans will develop life-threatening cancers. Nearly 600,000 will die. Dr. William Grant, founder of the SUNARC Foundation, estimates that 47,000 of those deaths will result from internal cancers that could have been prevented by adequate UVB exposure and consequent vitamin D synthesis (Grant, personal communication).

As a recent leading article in Fortune magazine has pointed out, the war on cancer has so far been a failure.

We simply cannot afford to throw away such accomplished and creative scientists as Michael Holick. In my opinion, Dr. Gilchrest and Boston University should reverse this misguided decision, pin a medal on Dr. Holick's labcoat, and get down to the business of finding innovative ways of preventing this terrible disease. The public deserves nothing less.

To order a copy of Dr. Holick's book, The UV Advantage, click here.

Action Alert

The Dermatology Department at Boston University invites the public to send comments, suggestions and concerns. Those wishing to comment on the case of Dr. Holick should click here.

I have received copies of dozens of letters so far and urge those of you who have not yet expressed your opinion on this matter to do so now. I would appreciate receiving a copy of any of your comments and letters and with your permission may print some of them in a future issue.

--Ralph W. Moss, PhD

For References associataed with the above article, click here to read the original at Dr. Moss's site.

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