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Vitamin D And Breast Cancer Redux: Caution Ahead

by Dr. Len June 01, 2008

A couple of weeks ago, I wrote a blog about vitamin D deficiency and its impact on breast cancer recurrence.  The information was based on an abstract that had been released in advance of the American Society of Clinical Oncology’s annual meeting, currently underway in Chicago.


In that blog, I reported on the conclusions of the researchers from the University of Toronto, Canada, that outcomes for women with breast cancer were worse if they were vitamin D deficient at the time of diagnosis, compared to women who had sufficient amounts of vitamin D in their blood.


Yesterday, the researchers presented their paper at the ASCO meeting.  And that presentation emphasized the fact that what appears in an abstract is not always the whole story.


The basic results reported at the meeting were essentially the same as those in the abstract.  Adequate levels of vitamin D in the blood of newly diagnosed breast cancer patients were associated with a less aggressive cancer and a better prognosis.


But there were two important points that were made that were in fact different from what was in the abstract or weren’t in the abstract at all.


First, during her presentation, Dr. P.J. Goodwin, who was the lead author on the study, commented that unlike what was printed in the abstract about the vitamin D relationship only pertaining to women with hormonally sensitive (estrogen receptor (ER) positive) breast cancers, in fact the study data showed that higher vitamin D levels were associated with an improved prognosis of all women with breast cancer—whether or not their cancers were hormonally sensitive.


That is an important point, since ER negative breast cancers—although representing a minority of breast cancers—are known to be more aggressive.  If vitamin D levels didn’t influence their prognosis, then that would represent one more negative differentiating factor for women diagnosed with these tumors.


Another interesting corollary—although not addressed specifically in this abstract presentation—is the fact that recent research has shown that African American women have a greater proportion of ER negative breast cancers. They also have more aggressive disease, with presentation at younger ages and with higher mortality compared to white women.  (It remains unclear how much of this difference is related to biology vs. lack of access to affordable, adequate health care.)


African Americans are also known to have a greater prevalence and degree of vitamin D deficiency.


If that is the case, then there is an intriguing question of whether or not there is a link here.  If we addressed vitamin D deficiency in African American women, could we reduce their risk of developing ER negative breast cancers, and improve their prognosis once diagnosed?


The second point that was presented in yesterday’s session was not addressed in the printed abstract.  Yet, in my opinion, it is possibly one of the most important observations regarding vitamin D being used to decrease the risk of cancer.  It is critical to assessing  the claims of many researchers and others that vitamin D supplementation is not toxic, and that we should be routinely recommending large doses of vitamin D through supplements or UV exposure to prevent cancer.


Dr. Goodwin showed a slide which looked at mortality in the women who participated in this study, based solely on their measured vitamin D levels.  (Unfortunately, I have not been able to get hold of a copy of this slide.)


The finding as reported, from my point of view, was unexpected and certainly should provide us with a sense of caution as we pursue to question of vitamin D as a cancer prevention agent.


The slide showed death rates over time as a function of vitamin D levels in these women with newly diagnosed breast cancer.


As would be expected, increased deaths were seen with low levels of vitamin D.  That in large part was due to increased deaths from breast cancer.


As vitamin D levels in the blood at the time of diagnosis increased, there was a fall-off in deaths, again probably due to fewer deaths from breast cancer.


But then there was the unexpected finding that as vitamin D levels increased, death rates increased as well.  That should not have happened from breast cancer, since the data was clear that higher levels of vitamin D were associated with better prognosis.  So something else was leading to more deaths than expected.  (For the scientists among you, this is what we call a “U” shaped mortality curve—increased deaths at the upper and lower limits of the measured variable, with a low level in the middle.)


What Dr. Goodwin reported was that there essentially was a “sweet spot” for blood levels of vitamin D that maximized its benefit with respect to breast cancer, while minimizing harm.  But the data also suggests that increased levels of vitamin D were in fact potentially harmful.


Dr. Goodwin mentioned that she did not know why this happened, and that it merits further research as to the cause as well as careful evaluation in upcoming studies.  She cited prior research that has suggested higher blood vitamin D levels may be associated with an increased number of cardiac events.


In any event, this is the first time I have heard of a potentially harmful relationship of this type, implying that we should be cautious before we recommend megadoses of vitamin D for women for the prevention of breast cancer, or as part of their treatment.


So what are the lessons?


First, what we see in print in an abstract is frequently never the whole story, and we don’t have the “final word” until a study is actually published in a peer review journal.  Even then, research studies are always subject to further discussion and scrutiny.


In this situation, the abstract said the benefits of higher vitamin D levels were limited to women with ER positive cancers.  In the presentation yesterday, we heard that women with both ER positive and ER negative breast cancers who had higher levels of vitamin D in their blood had better prognoses.


Second, there may be harm with having too much vitamin D in the blood.  This is very much a preliminary observation, and clearly needs more study to help us understand if this is a consistent, real finding. 


As I have noted before, we must always approach new ideas with caution.  We need to do the appropriate research to demonstrate both the benefits and the risks of vitamin D before we make recommendations for millions of people.


Only then can we have the confidence that the recommendations we are making are backed by the strongest and best scientific studies, and won’t result in more harm than good.

Filed Under:

Breast Cancer | Prevention | Vitamins

Sunwise and Sunsafe

by Dr. Len May 22, 2008







May is Skin Cancer Prevention Month.  




So it is never a bad idea to remember that being out of doors is a good thing.  But you should always make certain you are adequately protected.


The American Cancer Society suggests you remember the phrase “Slip, Slop, Slap!”  when you are enjoying yourself in the sun.


What does “Slip, Slop, Slap” mean?

Slip! - Slip on a shirt. Wear protective clothing when out in the sun. Choose clothes made of tightly woven fabrics that you can’t see through.

Slop! - Slop on sunscreen. Wear sunscreen with a sun protection factor (SPF) of 15 or higher on any exposed skin. Apply sunscreen 15-20 minutes before going outdoors, and be sure to reapply as necessary, especially after swimming, sweating or toweling off.

Slap! – Slap on a hat. Wear a wide-brimmed hat that shades the face, neck and ears.

And, while you’re at it, don’t forget to wear sunglasses that block 99-100% of the UV rays that can damage the skin and the eyes.

Sunscreen is probably one of the most misunderstood products we use.  Some people confuse high SPF values with all day protection.  It doesn’t mean that a higher SPF lasts longer.  It just means that it is stronger in blocking the sun’s rays.

So remember to use lots of sunscreen (about a palmful) and reapply it regularly—like it says above--especially after swimming, sweating (after a tough game of beach volleyball would be a good example), or drying off after coming out of the pool or ocean.  

My message about sunscreen: use it or pay the price!!!!!  Sunburns are bad for you, and what’s more, they HURT!!!!  But I suspect you already know that, probably from personal experience.  So why do you keep going back for another one?

You should also cover up as much as possible, and stay under the shade.  My wife and I have learned that reading, relaxing, and enjoying a beverage while under a beach umbrella or one of those beach huts works just as well if not better than baking and wrinkling your skin in the blazing sun.

Be especially careful during peak sun hours, which usually run from 10-4.

You can actually check on the projected degree of risk from the sun by looking up the “UV Index” online on the EPA Sunwise website.The EPA website will give you all the information you need to understand the UV index and what it means for your day in the sun.

The bottom line message that I try to give people about sun exposure is to enjoy it and use the sun wisely.  I don’t recommend seeking the sun to replenish vitamin D.  There are supplements that do that much more safely than the sun.

You can’t ignore the fact that we enjoy being outdoors, just like I am going to enjoy my weekend with my family.  Being outdoors is part of a healthy life style.

By taking a couple of sensible sun-safe precautions, it can also be part of a long and healthy life, free of skin cancers that sometimes can kill.

So, ENJOY!!!!

Have a safe and happy holiday weekend, and on Monday take a moment to remember those who have given their lives to make ours better.


Filed Under:

Other cancers | Prevention | Vitamins

Vitamin D And Breast Cancer: What Does It Mean?

by Dr. Len May 16, 2008









Based on what I do have available to review at this time, this study certainly appears to be well done and will likely raise as many or more questions than it answers.


According to the abstract, the researchers at 3 University of Toronto (Canada) hospitals took blood samples from 512 women who were diagnosed with breast cancer.  The women studied were all diagnosed between 1989 and 1995, and the course of their disease was followed until 2006.


What the researchers found was very interesting.


37.5 % of the women had low vitamin D levels which were considered deficient.  38.5 % had intermediate levels, or what the researchers called “insufficient.”  The remaining women—24% of those studied—had adequate levels of vitamin D at the time of their diagnoses.


The researchers found that there was a seasonal variation associated with vitamin D levels, as would be anticipated, with higher levels when the blood was drawn in the summer, and lower levels when the diagnoses and blood drawing occurred in the winter.


There were some other factors that were associated with vitamin D levels, including lower vitamin D levels in women who drank less alcohol, or consumed lower amounts of vitamin E, grains and retinol in their diets.


Premenopausal women and those with higher body mass indexes—a measure of overweight and obesity—also had lower vitamin D levels.


But here is the part of the research that is so interesting:


The time to recurrence of breast cancer was significantly lower in women with insufficient vitamin D levels, compared to women with adequate vitamin D levels in their blood samples.  Overall survival was also significantly better in women with adequate vitamin D as compared to those who were deficient.


For women with estrogen receptor negative breast cancer—which is known to be a more aggressive form of breast cancer—their survival was not related to their vitamin D status.


As noted in a press release that accompanied the abstract, “after 10 years of follow-up, 83 percent of women with adequate levels remained free of metastases and 85 percent were still alive, compared with only 69 percent and 74 percent, respectively, of women with vitamin D deficiency. Most of these deaths were attributed to breast cancer.”


The conclusion of the researchers was simple and straightforward in the abstract:Vitamin D deficiency is common at breast cancer diagnosis and is associated with poor prognosis.”


In the same press release, the researchers clearly pointed out that these results need to be confirmed by a second trial, which is already underway.  If that research supports these findings, then, as noted by the lead researcher on the team, they “recommend(s) a new randomized clinical trial examining the effects of raising blood levels of vitamin D on outcomes in women with breast cancer.”


As I mentioned, this is certainly a provocative study. 


There are certain things we look for in studies of this type, including the fact that the women were not selected at random, but represented all the women who presented for treatment of their breast cancer who met certain criteria.  The blood levels were obtained at the same equivalent time, namely when the cancer was diagnosed.


There has been a lot of research published on vitamin D and its relationship to cancer, some of which has supported a possible role of vitamin D in reducing the incidence of various cancers, other research suggesting that higher vitamin D levels at the time of diagnosis of certain cancers may be associated with an improved prognosis, and other research claiming the role of vitamin D in cancer incidence is limited.


We struggle with what to tell people to do when it comes to vitamin D and their health.


Clearly, the evidence indicates that vitamin D benefits bone and muscle health.  It may also influence cancer and other diseases such as autoimmune diseases and multiple sclerosis.


Yet when it comes to understanding vitamin D levels of people in the United States and elsewhere, we have much to learn.  We know many people—especially those with darker complexions and the elderly—have vitamin D deficiency. 


We don’t routinely measure vitamin D levels as part of a routine physical, yet maybe it’s time for us to consider doing that. 


Many experts believe that the current dietary guidelines for daily vitamin D intake are too low.  Some advocate daily sun exposure to maintain vitamin D levels, while the American Cancer Society and others say that you should not “seek the sun” for vitamin D replacement.  That’s because there are risks to daily sun exposure, and there are safer alternatives in over-the-counter vitamin D3 supplements which avoid skin wrinkling and increased risk of skin cancer over time.


With all of these questions and all of these controversies, it is time to move forward and get the answers.


I applaud the caution of the Canadian researchers in tempering the expectations that will inevitably follow the release of their report. 


They emphasize that we need to confirm their results, and if that confirmation does occur, then we need to do a clinical trial to determine whether vitamin D supplementation can influence the incidence of breast cancer.


We also need to focus our resources in bringing together knowledgeable experts to guide us on the appropriate daily vitamin D dietary recommendations.  We need to do the studies that will answer the question whether or not vitamin D does reduce cancer risk, and for which cancers.


As I have said before and will continue to say, there is enough research that has been published which suggests there is a relationship between vitamin D intake, vitamin D blood levels and cancer risk and incidence. 


But the type of studies that have to be done to provide us with the best evidence have not yet been done.  Those studies will require a significant commitment of researchers, money and willing participants.  They will take years to complete.


The problem I have is that in the past we have had suggestions that various vitamins reduced the risk of cancer.  When properly studied however, those claims didn’t hold up.  Not only did they not hold up, in some cases they were actually associated with an increased risk of harm. 


The conclusion: just because it’s a vitamin doesn’t mean it doesn’t have risks.


I am looking forward to hearing this presentation in Chicago in two weeks. 


I suspect I will come out of that meeting with the same thoughts I have going in, namely that we need to find out whether vitamin D is really the miracle vitamin that some claim, or is just another example of a failed hope that didn’t survive the careful scrutiny afforded by a well-designed clinical trial.


Millions of people are awaiting the answer.




I will post links on this story at a later time.





Filed Under:

Breast Cancer | Prevention | Vitamins

Conflicts Of Interest, Tanning, and Your Health

by Dr. Len April 24, 2008

If you want to understand why some of us are concerned about conflicts of interest, you need go no further than an article that appeared in last Friday’s edition of the Cancer Letter.


The article, written by Paul Goldberg, goes into great detail to explain why a scientific review on vitamin D, sun exposure and tanning booths which appeared in the New England Journal of Medicine last July may have been influenced by tanning industry funding.


The fallout from this conflict, in my opinion, may have substantial negative impact on how we are able to regulate tanning bed use, especially among young women who are putting their health at risk from the adverse effects of articial tanning.


The story is not new to regular readers of this blog.  I covered it in July 2007 when the review article first appeared in the New England Journal.


Essentially, the article was a review article on vitamin D and its potential role in health and disease.  As I noted at that time and on many occasions subsequently, I admired the depth of the science in the report regarding vitamin D and how it relates to human health.


Where I had a problem was that the author, who is widely known to be supported by and supportive of the indoor tanning industry, failed to make any comment in the article about the potential harms and risks of his recommendation that we should get regular sun exposure to get adequate amounts of vitamin D.  He also recommended tanning salons as an effective and safe means of getting vitamin D.


What he didn’t do was comment on the fact that there are many well-qualified experts in this field who disagree with his recommendations.  These experts don’t dispute the need to better understand vitamin D as it applies to our population, or that there is a role for vitamin D as part of being healthy.  The evidence is strong that vitamin D plays a role in muscle and bone health.  There is evidence that suggests vitamin D may play a role in cancer prevention. 


These experts feel that the recommendations for sun exposure and using tanning salons to increase vitamin D levels in our bodies do not take into account the risks of skin cancer that would result.  Nor do these recommendations take into consideration the realities that we are all different in where we live, the color of our skin, and our individual sensitivity to sun.  All of these factors and others influence our sensitivity to sun and how much vitamin D we produce in our bodies from sun exposure.


These experts feel that there is a safe alternative to get vitamin D into our bodies, either through our diets (which admittedly is difficult to accomplish) or through inexpensive, safe dietary supplements which are available at virtually every supermarket, drug stores and many other retail outlets throughout the country.


The Cancer Letter article makes the same points I did in my blog last July, and expands in greater detail to show how a conflict that is not recognized or declared can influence a host of subsequent events.


Basically, what happened in the New England Journal article was that the author acknowledged his research was supported by the Ultraviolet Foundation.


Google the Ultraviolet Foundation and its tax filings and you find out that it is funded by the Indoor Tanning Association. 


And that is not a conflict that should be considered in editing or publishing an article on vitamin D and health?


The Cancer Letter notes that the amount of support in question is small when viewed as a totality of the research support for the author.  But it was significant enough in this circumstance to be noted as a source of funding for the research that led to the publication of the article.


One needs to take a look at what I call “second level effects” of such events.


Maybe the author and the New England Journal consider the conflict of interest to be immaterial.   The potential fallout and damage is not.


Here is a possible scenario of how these things play out, and what in fact is happening right now:


The New England Journal of Medicine is one of—if not the—finest and most highly regarded medical journals in the world.  It is viewed as an authoritative source of medical information, and its influence in scientific, medical and legislative arenas is without peer.


As a result, having research published in the New England Journal provides a widely accepted “stamp of approval” on the research reported, or the information provided in a review article.


Since the editors and reviewers of the article did not see any reason for the author to address the concerns of many experts regarding the risks of tanning and sun exposure—even a sentence or two would have been sufficient—the article stands alone as a firm recommendation on the value of sun exposure and tanning beds as a means of getting vitamin D into our bodies.  (I should note that supplements were also offered as an option.  I am concentrating here on the absence of comment by the author on the risks of tanning beds and sun exposure.)


There are a number of states that are considering or have implemented legislation and regulation of tanning bed use, particularly by young women who represent a population at risk that use these services.


If you have watched legislation and public policy being formulated and debated, you know it is not always a pretty process.  It is usually not very deliberative—legislators always have many items on their agendas, and too little time to do much independent research or investigation.


That’s where this article comes in.  


An article in a prestigious medical journal which makes positive comments about tanning booths is invaluable when lobbying legislators. What could be more authoritative in making the case that effective regulation of this potentially life-threatening device is unnecessary? 


Now maybe you can appreciate why I am so concerned about this particular conflict of interest.


This scenario is not so far fetched. 


The Indoor Tanning Association has embarked on a nationwide advertising campaign to influence people--including state legislators--that tanning is safe, and actually healthy for you. 


Unfortunately, I can’t link to a copy of an ad which recently appeared in the New York Times.  What you see, in large print, is the statement, “Tanning Causes Melanoma.”  Superimposed over that is a “stamp” that says, in bold letters, “HYPE.”  At the bottom of the ad is a link to a website called “SunlightScam.com.”


Although I can’t find much in the way of true scientifically valid supportive evidence on the website, I can’t help but think somewhere someone is using the New England Journal article to support the claims of “hype” and “scam.”


Maybe I am moving with the wrong crowd on this one. 


My problem is that the experts I rely on don’t think that the claims of increased risk of skin cancer and melanoma are a hype or scam.  They do acknowledge that not all melanoma is caused by sun exposure, but they do note that sunburns in youth are a major risk factor for melanoma later in life.  And ultraviolet light—definitely UVB and quite possibly UVA—are the major risk factor for skin cancer.  Skin cancer is not always “benign”.  It can be fatal (melanoma) or very disfiguring when treated (squamous cell and basal cell carcinomas).


Perhaps you can now appreciate why understanding conflicts of interest are important, and that they are not trivial.  Many of us involved in medical science and medical leadership have conflicts.  They are almost unavoidable.


It’s not the conflicts that are always the problem (although in an increasing number of circumstances, they are in fact problematic).  It’s the recognition of the conflict, the declaration of the conflict, and the mitigation of the conflict that offer us the best hope to enable us to continue to maintain our trust in our most valued institutions, researchers, and leaders in medicine.


As I have said recently in another blog, it is up to the professions to deal with conflicts of interest issues and give them the visibility they deserve. 


Only through awareness, discussion and full disclosure will we be able to move forward and maintain the trust that the public has vested in us as physicians and medical scientists.

Filed Under:

Other cancers | Prevention | Vitamins

Maybe Vitamin D Isn't The Answer After All

by Dr. Len October 30, 2007

We have been bombarded over the past couple of years with scientific articles suggesting that vitamin D is the key to improving many aspects of our health, including reducing the risks of dying from cancer.


An article in this week’s Journal of the National Cancer Institute reminds us that perhaps we should be a bit cautious in embracing vitamin D as “the answer” before we do more research.


The report, from the National Cancer Institute and the Centers for Disease Control and Prevention, concluded that vitamin D levels in the blood were not related to overall cancer mortality. 


However, the study did find that higher levels of vitamin D were associated with a substantial decrease in the risk of dying from colorectal cancer, and possibly with a reduction in the risk of dying from breast cancer.


The study was performed between 1988 and 1994 and was designed to examine the health and nutritional status of the noninstutionalized United States population.


As part of the study, the researchers took baseline blood samples, which included a measurement of serum vitamin D levels.


16,818 people were part of the study which continued with follow-up through the end of 2000.


The researchers also monitored a number of factors including race/ethnicity, the latitude where the people lived (which would be expected to influence vitamin D levels through sun exposure), smoking, educational levels, and physical activity among other variables.


When they analyzed the data, they found that 536 people had died from cancer.


Higher levels of vitamin D were found in men, whites and those who were more highly educated.  Women, African and Mexican Americans, and less educated participants had lower levels of vitamin D in their blood tests.


Those who were more overweight and obese had lower blood levels of vitamin D than those who were thinner.  We know that fat tends to store vitamin D and reduce serum levels so this was no surprise.


Greater degrees of physical activity were also associated with higher vitamin D levels.


The key finding of the study was that there was no impact of vitamin D levels on the overall risk of dying from cancer, when comparing groups based on where they lived or what season their blood test was drawn (spring and summer would be expected to increase vitamin D levels, compared to winter).


Vitamin D had no impact on cancer deaths when various racial/ethnic groups were examined.


When the researchers broke down the risks of cancer deaths based on a number of cancer sites, the only significant reduction they found was for colorectal cancer.  In this cancer, those people with higher levels of vitamin D had a risk of dying from this disease that was 72% less than people with lower levels of vitamin D.


Although the data for breast cancer was suggestive of a protective effect of vitamin D, the numbers were insufficient to rule out other possible explanations for the decreased risk of death from breast cancer noted in the study.


Why would this study find results that appear to contradict the several other studies that have recently reported decreased risks of cancer deaths for a variety of cancers?


First, let me be clear: no study is perfect—even this one.  Many other studies that have been reported to show a decrease in cancer deaths related to higher vitamin D intake or sun exposure have been done by excellent researchers from highly regarded institutions.


This study stands out because it was done prospectively.  That means the participants were followed looking forward, and there were actual blood tests which measured vitamin D in the blood.


Many of the other studies have tried to infer vitamin D levels through a variety of means, such as asking about dietary habits or inferring a vitamin D level based on descriptions of outdoor activities.


That doesn’t mean that one study is right and the other is wrong.  It simply means that different researchers have reached different conclusions based on the analysis of different types of information.


For example, in this JNCI study, the numbers of certain cancer deaths may have been too small to reach an accurate conclusion.  Or, perhaps the follow-up wasn’t long enough, or perhaps the impact of vitamin D would have been greater if the blood test had been performed in younger people who were then followed for many more years.


The authors note that their results do not support the theory that low vitamin D levels contribute to the higher cancer deaths rates among African Americans in this country.


The researchers also write that their study had only small numbers of cancer deaths for certain cancer for certain ethnic and season/latitude subgroups.


They concluded with a statement that “additional studies with large numbers of samples of measured (vitamin D) levels, preferably at multiple time points, are needed to confirm the total cancer mortality findings of this paper and to obtain more accurate risk estimates for mortality from specific cancers.”


An editorial in the same issue of the Journal agrees.


The editorialists point out that it may take longer than 6-12 years of this current study to see the benefits of higher vitamin D levels, especially since it can take many years for a cancer to develop.  They also point out that it would have been better to have blood samples done at multiple points in time, since a single sample may not reflect the actual vitamin D levels over time.


They point out that we need to know more about how vitamin D levels change from season to season, and how that impacts our health.  We need to have a better understanding about the relationship between skin pigmentation and the response to ultraviolet B radiation to increase blood levels of vitamin D.


I particularly appreciated the conclusion of the editorial:


“Whether vitamin D reduces cancer risks and, if it does, whether these amounts suffice are actively being debated.  Randomized clinical trials of the effects of vitamin D on the incidence of colonic polyps and invasive cancer are needed.  While vitamin D may well have multiple benefits beyond bone, health professionals and the public should not in a rush to judgment assume that vitamin D is a magic bullet and consume high amounts of vitamin D.  More definitive data on both benefits and potential adverse effects of high doses are urgently needed.”


I couldn’t agree more.


Since vitamin D has come into the spotlight, I have transitioned from being a skeptic to believing there may in fact be a role of vitamin D in reducing the risks of a variety of cancers.  The evidence has been inferential, but I can’t ignore the weight of that evidence suggesting that such a relationship exists.


But the American Cancer Society has resisted the temptation to draw the conclusion that we currently know enough to make a general recommendation to the more than 300 million people in this country (and throughout the world) that they should markedly and routinely increase their vitamin D intake.


 (I will say that we recommend the safer route of dietary supplements as opposed to increasing sun exposure for those who make their own decision to pursue a higher level of vitamin D.   Seeking the sun for this purpose is, in our opinion, not the way to go to accomplish this goal, especially when supplements are safer and avoid the long term cumulative risks of skin-aging and skin cancer.)


We have consistently called for more research into this topic.  This is especially important given our past experience with other vitamins, such as vitamin C and beta-carotene, where well-qualified experts touted the benefit of those vitamins in reducing cancer risk.


When the studies were actually done, we discovered that the vitamins had either no effect or, for some people, may have actually increased their risk of cancer.


So what is the bottom line?  Is this study the end of the vitamin D debate (except perhaps for colorectal cancer and breast cancer)?


I don’t think this study should end the discussion of the possible role of vitamin D in cancer prevention, any more than I think the other studies answer the question that we need to embark on a major nationwide effort to increase vitamin D intake to supernormal levels.


We need more research, we need more information, and we need to answer the question definitively.


Until we get those research studies—and right now no one to my knowledge has undertaken the massive clinical trial it would take to answer the question—it is essentially an individual decision what to do, perhaps in consultation with your medical professional.


We do not have all the answers about the possible benefits of vitamin D in preventing cancer (or lack thereof), and we don’t have all the information about the risks.


Hopefully, as this debate continues, we will be able to move the research agenda forward and provide solid answers and guidance to replace the uncertainty which many of us currently face regarding the role of vitamin D in cancer prevention.


As I have said previously, this isn’t over.  Stay tuned….

Filed Under:

Colon Cancer | Prevention | Vitamins

Vitamin D and The New England Journal of Medicine

by Dr. Len July 18, 2007

An article in today’s New England Journal of Medicine is bound to get a lot of attention, but not for all the right reasons.


The article is a review of vitamin D deficiency and the implications for health and disease.


It is written by a researcher who is well known in vitamin D circles, Dr. Michael Holick from the Boston University School of Medicine where he is a member of their Vitamin D, Skin and Bone Research Laboratory.


What is perhaps less well-known is Dr. Holick’s close relationship with the tanning industry.


Many might end up asking why the Journal would choose someone widely viewed as having a pro-sun exposure and tanning bias to author an authoritative review on the subject, and why they would allow funding from the indoor tanning industry to play a role in the work.  You would have difficulty finding this information unless you knew what to look for and where to look.


Vitamin D issues are no stranger to this blog.  I have written several postings reflecting a changing personal viewpoint on the impact of vitamin D on health, particularly with respect to cancer.


My position has been that the evidence has increasingly suggested that there is a role between vitamin D and cancer incidence, and that further research needs to be done to confirm the apparent positive effect of vitamin D supplementation on reducing the risks of developing various cancers.


Essentially, given the research on vitamin D, we do feel that the question of adequate vitamin D intake needs to be addressed on a national basis by the appropriate scientific advisory bodies to determine whether the current recommendations for daily intake need to be increased.


Also, recognizing that there are three primary means of increasing vitamin D intake—through vitamin D rich foods, sun exposure and supplements—we continue to advocate sun-safe behaviors.  We do not advocate seeking the sun to increase vitamin D, which leaves us with the safe and effective alternative of recommending vitamin D supplements (in the form of vitamin D3) to ensure adequate levels of vitamin D in our bodies.


As to the “correct” level of supplements, some organizations have recommended increasing vitamin D3 daily supplement intake to 800-1000 IU daily.  However, it is our opinion that we need the national standard setting bodies to take a close look at the evidence and make a recommendation, before we can formalize a recommendation that will apply to over 300,000,000 people in the United States and elsewhere.


Now, back to the article.


This is actually a very detailed, in depth scientific review of a very complex subject. 


If you are interested in the topic of vitamin D, how it is made, how it works in the body, and other similar issues, and you are willing to wade through the medical and scientific language, you will likely find this article very interesting and informative. 


The critical role of vitamin D in preventing osteoporosis and fracture as well as its positive impact on muscle strength and reducing falls in the elderly is discussed in this report, which is probably the one reason all experts agree we need to increase vitamin D intake and blood levels.


The report goes on to discuss the role of vitamin D in a number of disease states, including cancer, autoimmune diseases, osteoarthritis, and diabetes among others. 


The causes of vitamin D deficiency are highlighted in one of the tables in the article. 


The most pertinent causes of vitamin D deficiency for most people, according to the author, include sunscreen use, skin pigment (the darker your skin, the less vitamin D you make from sun exposure), aging, seasonal/location/time of day factors, and obesity (fat holds on to vitamin D).


So what are the author’s recommendations to increase vitamin D in the body?


The first recommendation is to increase supplements to 800-1000 IU vitamin D3 daily in those children and adults who are “without adequate sun exposure.”


The author also provides a detailed text and tabular series of recommendations on how to prevent and treat vitamin D deficiency.


High on the list of recommendations for various states of deficiency are the phrases “sensible sun exposure,” “use of tanning bed or other UVB radiation device (e.g., portable Sperti lamp),” and “adequate exposure to sun or ultraviolet radiation.”


The author specifically says that for patients with mild or moderate hepatic failure or intestinal fat malabsorption syndromes and other medical conditions, “exposure to sunlight or ultraviolet B radiation from a tanning bed or other ultraviolet B-emitting device is also effective.  Sensible sun exposure can provide an adequate amount of D3, which is stored in body fat and released during the winter, when vitamin D3 cannot be produced.”


To achieve this, the author recommends “exposure of arms and legs for 5 to 30 minutes (depending on time of day, season, latitude, and skin pigmentation) between the hours of 10am and 3pm twice a week is often adequate.”


He goes on to say, “Most tanning beds emit 2-6% ultraviolet B radiation and are a recommended source of vitamin D3, when used in moderation.   Tanners had robust levels of 25-hydroxyvitamin D…at the end of the winter and higher bone density as compared with nontanners…  For patients with fat malabsorption, exposure to a tanning bed for 30-50% of the time recommended for tanning (with sunscreen on the face) is an excellent means of treating and preventing vitamin D deficiency.”


The article concludes, “Excessive exposure to sunlight, especially sunlight that causes sunburn, will increase the risk of skin cancer.  Thus, sensible sun exposure (or ultraviolet B irradiation) and the use of supplements are needed to fulfill the body’s vitamin D requirement.”


The problem I have with this recommendation is that I don’t know many experts who agree with the sun exposure or tanning-bed part of it. 


The experts are concerned about a number of factors, including the cumulative risks of unprotected sun exposure, the risks to individuals based on their skin pigmentation, the impact of geographic location and time of day when or where exposure occurs, and the fact that is difficult to impossible to make such a one-size fits all recommendation of this type when considering all of the individual variables.


But there is no question that the average person reading this article will come away with the impression that sun exposure and using tanning beds is “ok” as reported in the prestigious New England Journal of Medicine.


But in what may turn out to be the most interesting part of this story, the author acknowledges the support of the National Institutes of Health and the UV Foundation for his research. And while he reports receiving honoraria from several pharmaceutical companies, he did not indicate any similar payment  from the other sources, such as the tanning industry.


A quick check of the Web finds Holick makes no effort to hide his associations with the UV Foundation and another group called the Indoor Tanning Association (ITA). The UV Foundation lists the Indoor Tanning Association, the Osram Company and Future Industries as its major supporters. The purpose of the Indoor Tanning Association is obvious.  The Osram Company makes light bulbs.  Future Industries makes tanning beds, light bulbs and associated tanning paraphernalia.


Coincident to the publication of this article, many states, including California, are now considering new legislation or strengthening existing legislation restricting the use of tanning beds by young people (in fact, I find the timing of this article in the New England Journal as particularly interesting given the fact that California right now is considering a bill to strengthen the control of tanning bed use by young people).


My expert colleagues are not alone in their concerns about tanning beds.  The World Health Organization has issued a report on the cancer causing effects of tanning beds and recommended that people under the age of 18 should not use them.


On both the UV Foundation and ITA Web sites, Dr. Holick is prominently displayed, promoting his recent book touting UV exposure. There is even a link to his pod cast—right next to the ITA’s plea to help defeat the California “under 18 ban.”


So here we are:  a research report in the New England Journal of Medicine that contains a lot of excellent information, and is well written, well organized and very informative.


That said, there is clearly a substantial amount of discussion about vitamin D supplementation, but there is also a strong emphasis on “sensible sun exposure” through a variety of means, including direct exposure and tanning beds. 


On the other side of the recommendation a cadre of well-qualified experts who feel that this is a very dangerous and inappropriate recommendation.  But their views are not represented in the article.


Go figure.



Filed Under:

Diet | Prevention | Vitamins

Vitamin D And The Risk Of Cancer

by Dr. Len June 08, 2007











The women were all post-menopausal, with an average age of 66.7 at the time they entered the study.  As a group, they were overweight, bordering on obesity with an average BMI of 29 (a BMI of 25 to 29.9 is considered overweight; greater than 30 is obese).


The researchers determined how many women in each group developed non-skin cancer AFTER having participated in the study for one year.  The researchers made that arbitrary cutoff in order to eliminate cancers that, in their opinion, may have already been present at the time the study began.


As I mentioned, the results were stunning: the risk of developing cancer over the four year time-frame in the women who took both the calcium and vitamin D was 78% compared to the placebo group. 


For women who took only calcium, there was a decrease of about 41% in the risk of developing cancer.


The numbers of cancers diagnosed from year 2 to 4 of the study were actually small (as would be expected in a study of this size): there were 18 cancers diagnosed in the placebo-treated arm of the study; 15 cancers in the calcium arm, and 8 cancers in the calcium/vitamin D treatment group.


The numbers of cancers for any particular tumor type were also small, and included cancers of the breast, colon, lung, lymphoma/leukemia, uterine cancer and “other” cancers.


Because of these small numbers, it was not possible to determine whether any particular cancer type was especially affected by treatment with vitamin D.


What was apparent from the study was that taking vitamin D tablets did increase the blood levels of vitamin D, and that there was a direct correlation between these levels and the reduction of cancer incidence.


So where does this study fit into the bigger picture of vitamin D in relation to cancer prevention?


First, it is certainly a very intriguing and provocative report.


There have been many studies reported over the past couple of years suggesting that vitamin D can reduce cancer risk, and that more vitamin D in the body is correlated with a lower risk of several cancers.  In fact, in a previous blog, I mentioned that although I had initially been a skeptic of that relationship, I had been converted into a “believer” that in fact there may be such a relationship.


This study adds to that body of evidence.


Unfortunately, this study is simply too small to make an absolute conclusion that the relationship does in fact exist.  It is not sufficient in my opinion to make a major recommendation that everyone should start taking 1000 IU of vitamin D3 every day.


Why am I not convinced?


Bottom line, as I have written and commented previously, we need more research in this country to understand the basics of vitamin D in our United States population.


We need to understand the impact of geography, ethnicity, personal habits and many other factors on vitamin D levels. 


We need to determine whether we should in fact be measuring vitamin D levels routinely as part of preventive medical care. 


We need our major national research organizations who monitor this literature to get on with the process of reviewing the data and making evidence based recommendations on what the correct amount of vitamin D supplementation—whether in our diets or through pills—should be for our daily intake.


Perhaps most important is, in my opinion, the need for a well-designed, prospective trial to determine whether or not vitamin D actually reduces cancer risk.


There are too many other instances where the data has appeared compelling that a particular vitamin or drug that might prevent cancer.  This evidence is frequently based on what I will call indirect evidence.  Once the appropriate prospective trial was conducted, we too frequently find that the results were negative or worse.


The research into beta-carotene comes to mind.  A “harmless” vitamin, beta-carotene was thought to reduce the risk of lung cancer.  When it was put into a randomized, controlled prospective trial, however, it was found to actually INCREASE the rate of lung cancer.


In regards to the present vitamin D study, 4 years to me seems an awfully short time to demonstrate a true preventive effect of vitamin D. 


We know that many cancers take years to develop.  In fact, in my personal opinion, many of the cancers that this study concludes were “prevented” in fact were present at the time the study was started.


I suspect there is something else going on here, and it is not prevention.  It is more likely a direct effect on the pre-existing cancer, a slowing of growth, or some other phenomenon, but not prevention.  It is also possible that the effect may be due to some other, unrecognized factor (I want to be clear that this is not a criticism of the researchers, who are considered to be excellent clinical scientists by their colleagues).


Four years is simply too short a time to have this dramatic effect if prevention was the primary effect of vitamin D supplementation.


Finally, what we definitely do NOT recommend is that people start seeking the sun or use tanning beds as a source of vitamin D with the intent to decrease their risk of cancer.


Small amounts of sun exposure for this purpose are OK for most people, but each person has their own vitamin D and skin “personalities” that dictate their risk of skin cancer, and dictate how much sun exposure they need to get an adequate amount of vitamin D.  Where you live also has an impact on skin cancer risk, as well as the amount of vitamin D you might produce from a particular amount of exposure to the sun.


Ultraviolet rays have their own harms and are not a good way to get vitamin D.  That doesn’t mean you should be a hermit, but when you go outside—particularly when the UV index is 3 or greater—you should engage in sun-safe behaviors, such as wearing a shirt, wearing a hat, using plenty of sunscreen, and wear UV-protective sunglasses.


In the interests of full disclosure, my Canadian colleagues (and friends) at the Canadian Cancer Society have come out with an advisory today that suggests all Canadians take a daily supplement of 1000 IU of vitamin D.


The Canadians decided to move forward because of the fact that sun exposure in Canada is limited. 


My colleagues here at the American Cancer Society have decided not to make such a recommendation, pending additional research discussed above. 


We need our governmental agencies that review the evidence and determine the recommendations for dietary guidelines to start taking a careful look at their current vitamin D recommendations, so we can have clear guidance--based on currently available evidence on the role of vitamin D in cancer and other diseases—as to whether or not we should make a nationwide effort to increase vitamin D intake.


In the meantime, what should you do?


I can’t make a recommendation outside of the current guidelines, which are age and dose dependent.  It is up to you and your health clinician to determine whether or not you should be taking more vitamin D, based on your own personal risk profile.


You should be aware that the current study used 1000 IU a day of vitamin D3.  Other studies have shown lower doses of 400 IU daily did not decrease the risk of colon cancer in post-menopausal women (there were some issues with the design of that study), while another study looked at pancreatic cancer risk in men and found that 400 IU a day significantly reduced their risk of that disease.


In my opinion, it is time to make the investment in getting the definitive answers to these questions.


As I mentioned, the results of the study discussed here were impressive, but they are limited in their practical impact in my opinion.


We need to expand our understanding of the role of vitamin D in our health, and get solid answers to our questions so that we can find out once and for all whether or not this vitamin is truly the miracle that some claim it to be.


Filed Under:

Diet | Prevention | Vitamins

Vitamin D and You: Don't Forget Common Sense

by Dr. Len May 25, 2006

A couple of months ago I mentioned that I attended a conference in Toronto where we discussed the topics of ultraviolet radiation, vitamin D and health.


Today, the Canadian Cancer Society released the first public information from the conference, which was cosponsored by the American Cancer Society, the World Health Organization and other organizations from Canada, the United States and Australia.


Although we did our best to craft concise messages to help explain what we know and what we don’t know about vitamin D and your health, there is concern that those messages will not be understood by many folks. 


And, worse, there is the risk the messages may be deliberately misinterpreted to promote behaviors that are associated with significant increased risks to one’s health, particularly with respect to skin damage.


For an actual copy of the statement, please go to the posting on the Canadian Cancer Society website.


There is no dispute among medical professionals that vitamin D is beneficial for our health, and there is no dispute that sun exposure is the major source of vitamin D for most of us.


But there is also no dispute that exposure to ultraviolet rays type A and B (UVA and UVB) from the sun and other commercial sources can be harmful.  Skin cancers, melanoma and cataracts are all increased by UV exposure. 


In this country, over 1 million cases of non-melanoma skin cancer will be diagnosed in 2006.  Although many people think that skin cancers are simple and relatively “benign,” (have you heard the phrase, “If you are going to get a cancer, skin cancer is the one to get?”), the reality is that the treatment for some of these skin cancers can be disfiguring and devastating.


There will be about 62,000 folks diagnosed with melanoma, and 7910 people will die from this disease.  There will be close to 50,000 people diagnosed with melanoma in-situ, which means it is very early and doesn’t invade deeply into the skin.


And if you are young and still feel immortal, you need to be aware that the incidence of melanoma among young folks, although still rare, is increasing.  And, if that doesn’t scare you, take a look at your close relatives who have had a lot of sun exposure and admire their wrinkles.  They are in no small part due to the aging effects of the sun on the skin.


I think it is fair to say that there are many experts who are very concerned about the risks of sun exposure.


But does that mean that we should avoid the sun completely?  Should we slather ourselves in sunscreen every day before we walk out the door?   Should we not engage in outdoor activities that promote good health and well being, and which may be one of our key strategies to deal with the epidemic of overweight and obesity in this country?


The answer to that is a simple no. 


If we do elect to take a walk, play a sport, or go to the beach or the pool, we should pay attention to what the experts recommend for sun safe/sensible behaviors.  Using sunscreen, wearing a hat, wearing long sleeve shirts (when practicable), and wearing sunglasses are all recommendations that I believe are prudent.


It is also sensible to avoid the sun at the most intense times of the day, and if you must be outside during those times try to seek the shade.


But avoiding the sun at all costs, for most of us (there are people who are extremely sun sensitive) simply doesn’t make sense.


There is a simple index that is available that can give you a clue as to when the sun is too intense, and that is called the UV index.  The Australians and the Canadians pointed out during our discussions that this information is readily available in their country through radio and TV broadcasts, and I explained to them that it is much less available here.


But that doesn’t mean it is not a useful guide.  You can find the information on a variety of weather related sites, such as the Environmental Protection Agency.  A UV index of 3 or greater is the danger zone.


Given the fact that the sun is dangerous when exposure is excessive (the problem here is that some people think excessive means when you blister with a sunburn; to a “skin expert,” it is the dose of sun that is required to develop minimal redness in the skin.  That can be 30 minutes for me and 5 minutes for you, in no small part due to the type of skin you have and where you live), how does that relate to vitamin D?


Sun exposure is the one generally accepted means of getting vitamin D into our bodies. 


Fortified foods, such as fortified milk, are another.  There are some other foods that may contain vitamin D, such as certain types of fish, but my hunch is that most of us don’t eat those foods on a regular basis.  And, if a dairy product doesn’t specifically say it is fortified with vitamin D, it isn’t—and should be relied on as a source of vitamin D.  So those of you who like ice cream, sour cream, cottage cheese, cheese or whatever—if it doesn’t say fortified, it doesn’t have vitamin D.


The third source of vitamin D is vitamin supplements, which should be “vitamin D3” or cholecalciferol.  Other forms of vitamin D supplements don’t work as well. 


The potential problem here is the quality of manufacture of the vitamins and whether in fact they contain the vitamin in a formulation that will allow it to be absorbed by our bodies.


Also, if you take a multi-vitamin or a calcium supplement, check to see if and how much vitamin D is contained in the pill or liquid.


We know that vitamin D is proven to be good for musculoskeletal health and the prevention of fractures in the elderly.  It may also reduce the risk of certain cancers, including colon cancer (additional data has recently been reported in the Journal of the National Cancer Institute, and somewhat buried in the data from a recent report in the New England Journal of Medicine on a follow-up of the Women’s Health Initiative study).


We also know that we don’t know a whole lot about how much vitamin D we have in our bodies.  What evidence we do have suggests that those numbers are too low for many folks.  In particular, African Americans have a high frequency of vitamin D insufficiency, as do other people of color.


Now we come to the part that is difficult for many to understand.


If vitamin D is good for you, and exposure to the sun can be bad for you, what do you do?


What you do NOT do is seek the sun.  That would be absolutely the wrong message to send, and that is what has so many of us in the skin cancer prevention community so concerned.


In very real terms, what can be one person’s benefit can be another person’s poison. 


There are simply too many factors that have to be considered in making a “one size fits all recommendation.”  Factors to be considered include age, diet, skin pigmentation (as mentioned above), where you live (there is a big difference between Florida and northern Maine), and intensity of the sun (think Phoenix and Toronto in the summertime).


For some people, when we say a “small amount” of sun exposure, they may incorrectly interpret that to mean two hours.  For others, even 5 minutes of exposure in the wrong place on the wrong day can lead to a burn (I once got mild sunburn sitting at an outdoor restaurant eating a salad at lunch.  I have to admit that I was very surprised, to say the least, since I really didn’t sit there that long.).


So, although exposure to the sun may be an acceptable way to get vitamin D, it isn’t the safest way.  And if you decide to pursue this approach, make certain you use sensible behavior as discussed above.


And, above all, in my opinion and that of others, tanning beds are not acceptable ways to get vitamin D.  Put aside the risks of burning, and the harms of tanning.  The reality is that many dermatologists and others are very concerned about the lack of adequate controls on tanning beds, and the potential for long term harms of what is basically a social behavior.  In fact, the World Health Organization recommends that people under the age of 18 not be allowed to use tanning beds.  In my opinion, I can’t understand why anyone would want to expose themselves to a tanning bed.


For me, my recommendation is that supplements are the way to go, especially if you are in one of the categories “at risk.”  The elderly, exclusively breast fed babies, people who don’t get much time in the sun (like me and many of my colleagues whose only routine sun exposure is through the window at work), and those who live in the northern parts of the United States and Canada are examples of such groups who need special attention to their vitamin D intake.


But the right dose of vitamin D supplements still remains uncertain.  The consensus is that it is greater that the current recommendations of 200 IU/day up to age 50 and 400 IU/day through age 70, and 600 IU per day for those age 70 and older.  But we don’t know the answer yet.  One organization, Osteoporosis Canada, recommends 800 IU/day for adults over 50.


Also, we don’t know the truly toxic daily dose of vitamin D, which is now pegged at 2000 IU/day.


We still have much more research to do.  We need to know more about individual blood levels and how much vitamin D we need to maintain health.


We need to know more about what to recommend to the public about sun exposure.  The reality is that there are many variables to consider, so there is no likelihood that anyone can make a sound, science based argument that there is a single “sun prescription” that will be right for everyone in every place.


We need to know the long term risks of taking vitamin D supplements over a long time.


And we need to know the level of vitamin D that will reduce our risk of various health problems, including cancer.


The reality is that we know more about vitamin D and health today than we did a year ago.   But we still have much to learn.


But one thing has not changed over the past year, and that is our firm recommendation that if you decide to go outside, know the risks and protect yourself.  It’s up to you to be “sun safe and sun sensible.” 


Increasing your levels of Vitamin D is no excuse to ignore common sense.






Filed Under:

Diet | Prevention | Vitamins

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