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Revisiting The Sun
New Science Suggests More Sun, Not Less, Is What Most Of Us Need For Greater Health

By Mark Lundegren © 2005

In what has been a long, sometimes passionate, and decidedly behavior-changing debate about the risks and benefits of sun exposure, the pendulum has now begun to swing back once again toward the sun, away from life in the shade.  This time, however, the change may be a more lasting one, with the potential for a stable and far more informed scientific consensus about the importance and optimal needed amount of sun exposure.

As the dust, or rather the data, begins to settle in this debate, extending back centuries, our once revered and now frequently reviled sun is now far more likely to come out on top than it was just a few years ago.  This may not be surprising to some of us, who have wondered quietly how we evolved beneath the sun if we were not able to withstand its rays – and even what parts of our human physiology might be dependent on regular doses of sunlight.

In case you have been living deep in the jungle or beneath a rock, the dominant view has been and still is that sun exposure is bad, a carcinogen, especially during the midday hours and if you are fair-skinned.  If you have been following this accepted thinking, you may well have been living in a shaded jungle, or beneath or along the shadows of rocks and roofs.  In the least, you probably have steered your outdoor experience to early and late in the day, and have ventured out at midday only with a film of sunscreen applied to your exposed skin.

In either case, it is definitely now time to come out of the shadows you may have been living in.  While no one is likely to advocate prolonged sun exposure anytime soon, or allowing sunburns ever, it is time for us all to reconsider our views and even to begin to revisit the sun above us once again, firsthand and with our skin.

The Vitamin D Connection

What has caused this new and perhaps permanent turn in the debate about sun exposure is new research into the roles and effects of Vitamin D.  Vitamin D is really more of a pre-hormone than other vitamins, in that it fosters natural human steroid production, an essential component of our human physiology and health.

It has been known for some time that sunlight exposure was crucial to our natural production of Vitamin D, and that this production was in turn important to the health of our skeletal and nervous systems in particular, and to cellular metabolism in general.  More recent research has revealed the significant problems we can have in getting and keeping adequate Vitamin D in our system for our health in all these areas, especially if we are not in strong sunlight frequently enough, if we are not light-skinned, or if we are overweight. 

Dietary sources of Vitamin D come primarily from oily fishes like salmon, which have many other health benefits and are an essential part of a natural human diet.  But these dietary sources provide only small amounts of Vitamin D in comparison to the amount that can be produced though sun exposure, which is thus likely to be essential to ensuring adequate Vitamin D and our long-term health.

There are of course Vitamin D supplements and fortified foods, but these are generally problematic from several standpoints: 1) they are often provided in unnatural, health-reducing foods like calf’s milk, 2) they usually contain Vitamin D2 instead of the more desirable Vitamin D3, 3) they often are provided along with the canceling effect of a vitamin A supplement, 4) they may not reliably increase circulating Vitamin D in a way comparable to sunlight exposure, and 5) there is a risk of toxicity with high oral Vitamin D doses aiming to mimic the effects of sunlight exposure (sunlight-produced Vitamin D does not have this toxicity risk). 

Like dietary supplements in general, Vitamin D supplements are usually not a good substitute for real life, whether the subject is eating natural foods or getting natural sun exposure.  It is worth noting that HumanaNatura does not advocate supplementation of any kind for people on our natural diet plan, except on the advice of a physician.  A natural diet, informed by modern health science, is still by far the best way to obtain the optimum amounts and types of the many nutrients we need to ensure our health (nature’s billion-year head start on the supplement industry is indeed a formidable one).

Beyond the limited sources of Vitamin D in our natural diet and the various problems of supplementation, there is an added issue for people who are dark-skinned.  Research has shown that the impact of sunlight on Vitamin D production in dark-skinned people is much less than their lighter-skinned brethren.  Lighter-skinned people can get a significant Vitamin D boost in just 15-20 minutes outdoors in bright sunlight (on the order of 10,000 units of Vitamin D – a very healthy daily dose), reflecting an evolutionary adaptation favoring lighter colored skin in the upper latitudes (where there is often less and less strong sunlight with which to make Vitamin D). 

The response to sunlight is very different for darker-skinned people, who produce far less Vitamin D in strong sunlight and almost none in weak sunlight (even in midday sun in winter in upper latitudes).  This is an important finding for many of us.  When we talk about lighter-skinned people being adapted for weaker sunlight, it is a bit euphemism.  After all, what we really mean that this attribute has been naturally selected.  In earlier life in upper latitudes, slightly lighter-skin people maintained healthier physiologies than darker-skinned people, and had lower death and higher fertility rates, leading to a selection of lighter skin color over time.  For these reasons, darker-skinned people are health-disadvantaged in low sunlight conditions.  We’ll come back to this topic in a minute, including Vitamin D’s likely role in driving selection for lighter skin and the implications of this for natural health today.

Finally, to conclude our survey of the problems we may face in maintaining adequate circulating Vitamin D, we must also mention that overweight people have added problems with Vitamin D too.  Vitamin D is a fat-soluble compound and can build up in our fat cells, which is why toxicity from oral or dietary supplementation is an issue with Vitamin D.  It is also why overweight people can have much lower levels of free Vitamin D than average weight people, even with a comparable diet – Vitamin D generally gravitates to and stays in the fat cells of overweight people, instead of circulating more freely in our body.

The Sun & Cancer

As important as these findings are, there is still more to consider about the sun.  In fact, what is really new in the debate about sun exposure is recent research on the effects of high levels of Vitamin D in actually reducing, not increasing, cancer incidence and mortality (and thereby pointing to the likely mechanism for the natural selection of lighter skin complexions in upper latitudes). 

There are a growing number of studies supporting this linkage of Vitamin D and lower cancer mortality, most notably comprehensive research published in 2005 by Edward Giovannucci of Harvard University.  These results are still preliminary, but they are significant and will likely force a significant and permanent rethinking of sun exposure over the next few years. 

Ultimately, long-term objective studies will be required to settle the science of sun exposure, which will take time.  In the meantime, as I said before, the pendulum has begun to swing back toward the sun, and now with new and decidedly added momentum.

Here is a synopsis of what we now know about sun exposure today: 

  • The sun can cause skin cancer, including deadly melanomas, particularly in very light-skinned people who allow themselves to burn frequently over the course of their lives.  It is worth noting that non-melanomic skin cancers are usually treatable and unlikely to be fatal in developed countries.  Mortality from skin cancer appears to be especially linked to frequent sunburns when we are young.
  • Moderate sun exposure can dramatically increase circulating Vitamin D in light-skinned, non-obese people.  Darker-skinned people need much more sun to achieve high circulating Vitamin D levels.  Other sources of Vitamin D (both foods and supplements) provide much lower and probably inadequate levels of circulating Vitamin D as discussed above.
  • People with high levels of circulating Vitamin D appear significantly less likely to die of cancer (a variety of cancers) than people with low levels of circulating Vitamin D.  Initial estimates by Giovannucci are that high, sun-induced Vitamin D counts prevent 30 deaths for each death from skin cancer linked to sun exposure.  This is a remarkable ratio if it holds true in further research, one that will drive the re-thinking of a number of current public health policies.
  • Vitamin D is essential to long-term cellular health.  It appears to prevent the initial formation of cancerous cells, and more importantly, to significantly reduce the reproduction and spread of cancerous cells if they do emerge.  Recent studies point to much lower mortality rates from lymphoma and cancers of the prostate, lungs, colon, and even the skin, when high levels of Vitamin D are maintained through sun exposure.
  • In addition to cancer prevention,Vitamin D is essential to skeletal and bone health, and perhaps even more important than calcium intake in preventing many chronic diseases of the skeletal system, including osteoporosis.
  • Consensus is building that light-skinned people should be getting 15-20 minutes of direct sunlight (without sunscreen) several times a week, and this sunlight should be at midday during winter in upper latitudes.  If a person is at risk of burning with this amount of sun exposure, the consensus is that they should work up to this amount of sun gradually, taking care never to burn. Darker skin people need much more sun than this to maintain adequate Vitamin D, on the order of several hours a day of lower latitude sunlight (or summer sunlight in upper latitudes). 
  • It is unclear at this point how darker-skinned people can reliably maintain adequate circulating Vitamin D and a reduced cancer risk during the winter in upper latitudes.  This may be a difficult piece of news for many people, and the science is far from settled on this topic, but it is a cautionary note worthy of mention.  Already, it is well established that African-Americans have higher cancer mortality than European-Americans in the northern United States, just as native Europeans have more cancer mortality in light-starved regions like Scandinavia than in the temperate parts of Europe.  Vitamin D3 supplementation may be needed for darker complexioned people, as a partial substitute for regular time under the tropical or subtropical sun – this topic is certainly worth a conversation with your physician.

A New Day In The Sun?

You may have found this article because of my involvement with the HumanaNatura natural health community, and perhaps may know that I am an advocate of our pursuit of natural health (a term often misunderstood but carefully defined by HumanaNatura).

Part of this advocacy involves suggesting and encouraging dietary and lifestyle changes to promote greater health and well-being.  This includes a call to increase the amount of time we spend outdoors, away from modern civilization (to get perspective on it) and in wild nature (to reconnect with it and our natural selves).  Inevitably, this alternative life means more time in the wind and heat, and rain and, yes, even in the natural sunlight of nature.

For the last two or three decades, as consensus built against sun exposure, I have always felt uneasy about this aspect of my natural health advocacy work.  Perhaps, I’ve thought, the sun is one area where nature and natural life does not promote our health and well-being, an exception to what is otherwise a sound and pervasive general rule.  But alongside this uneasiness, as I mentioned before, I have always questioned this anti-sunlight consensus, since it seemed at odds with what we know about our human life and evolution in nature.

I always avoid sunburns and will use a sunscreen if there is a chance I will burn, and you should too.  This takes some attentiveness when you first spend more time outdoors, and then when you spend a great deal of time outdoors, as I sometimes do – often an hour or more each day and then even for entire days when I am on an extended walk or hike.  I should add that I occasionally use sunscreen lotions, although I prefer the more natural methods of wearing a hat and other protective clothing when I am in the sun for extended periods, and of seeking midday shade and enjoying a leisurely lunch with friends in the summer and when I am in lower latitudes.

Still, with all these preparations, I know I am getting more sun than many would advise today.  It is a personal choice I consciously make and I know there are risks and uncertainties.  For me, not being outdoors would mean be not being fully alive, not being fully human, so there are enormous immediate benefits for me balancing out my potential long-term risks.  If you spend time outdoors, I know you appreciate the freedom and joy that being out in nature inevitably is, each day of outdoor life, and understand that we are willing to give up things for a life of these experiences.

If you do not spend time outdoors, you may not understand my position and may disagree with the choices I make.  Before you condemn me completely, I would point out that the risks we face from the sun may be smaller than previously thought.  Indeed, it may turn out that I am actually healthier in the way I live than if I had spent the last two or three decades avoiding the sun more aggressively, as many have suggested.  It certainly feels that way, emotionally and physically, but I will wait with you to see what the science of the sun finally says.

In the least, perhaps you will now feel better about the sun, and may even venture out beneath it and into nature more like me, extending yourself across the land in an ancient and more open human pattern of life.  Perhaps you will try it just to experience the fuller life I have spoken about, to see if you can really be fully alive and human, and truly healthy, without a life in the sun.

 

Mark Lundegren is the founder of HumanaNatura. 

  

 

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