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.