“Still, none of these factors is as important in explaining the widespread levels of vitamin D deficiency as is the fact that as a society we are increasingly choosing to deprive ourselves of our most important source of vitamin D -- sunlight.
Exaggerated warnings about the perils of sun exposure are driving Americans to hide beneath long sleeves, floppy hats, and wraparound sunglasses and to slather every square inch of skin that isn’t covered with high-SPF sunscreens… The result of all this is to block out the sun that humans need to make vitamin D. The inescapable fact is that humans have evolved in such a way as to be dependent on sunshine for life and health…
Why does this matter? The short answer is that the benefits of vitamin D on human health are many, varied, and profound… Suffice it to say that in some respected medical circles, sunlight is being described as a ‘wonder drug.’ It can provide ‘immunity’ against some of the most devastating diseases around, including heart attack, stroke, osteoporosis, and certain of the most deadly internal cancers… Sunlight has a similarly dramatic effect on high blood pressure, one of the leading causes of heart attack and stroke -- people who spend time in the sun… experience a blood pressure-lowering effect similar to that of standard medications that have unpleasant side effects. We’ve found that sunlight has a beneficial effect on heart health equal to exercise. Then there’s bone health. Sun exposure helps build and maintain bone density and reduces fractures… Humans also need sunlight to control the biological clocks that regulate mood, and appropriate sun exposure is responsible for keeping down rates of depression associated with seasonal affective disorder (SAD) and premenstrual syndrome (PMS). Let’s not forget that sunlight plain old makes you feel better -- not something to be dismissed in this high-stress world in which many of us live.
…The drawbacks of sun exposure pale in comparison with the health benefits… Precautions do need to be taken, but a regular, moderate amount of unprotected sun exposure is absolutely necessary for good health…”
-- Michael F. Holick, Ph.D, M.D., The UV Advantage (ibooks, 2003)
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“Many scientists believe that ‘safe sun’ 15 minutes or so a few times a week without sunscreen is not only possible but helpful to health. One is Dr. Edward Giovannucci, a Harvard University professor of medicine and nutrition who laid out his case in a keynote lecture at a recent American Association for Cancer Research meeting in Anaheim, Calif. His research suggests that vitamin D might help prevent 30 deaths for each one caused by skin cancer. ‘I would challenge anyone to find an area or nutrient or any factor that has such consistent anti-cancer benefits as vitamin D,’ Giovannucci told the cancer scientists. ‘The data are really quite remarkable.’ The talk so impressed the American Cancer Society's chief epidemiologist, Dr. Michael Thun, that the society is reviewing its sun protection guidelines. ‘There is now intriguing evidence that vitamin D may have a role in the prevention as well as treatment of certain cancers,’ Thun said. Even some dermatologists may be coming around. ‘I find the evidence to be mounting and increasingly compelling,’ said Dr. Allan Halpern, dermatology chief at Memorial Sloan-Kettering Cancer Center in New York, who advises several cancer groups.”
-- Marilynn Marchione, Associated Press, May 23, 2005
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“After all the warnings that we should avoid the outdoors because prolonged exposure to sunshine causes skin cancer, a new study now suggests that staying indoors under artificial light for long periods may be even more dangerous. The Ecologist [British magazine] cites a paper in Britain’s authoritative medical journal The Lancet showing that Australian subjects who worked long hours under fluorescent lights had higher incidences of skin cancer than those who worked outside or frequently sunbathed.”
-- Jay Walljasper, Ode magazine, March 2006
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Winter is, of course, the season when the days are shortest and the sun’s rays are least direct. By February a growing number of us may be starting to feel sun-starved.
More abundant sunshine will be available by the time spring arrives. But on winter hikes we can greatly benefit from imbibing healthy doses of natural light.
The sun is a vital generator of life on earth, and the ways it affects us are becoming increasingly clear. Our bodies need full-spectrum light to function properly.
John Ott (1909-2000) was a scientist who researched the effects of natural (vs. artificial) light on living things. Among his books was Health and Light (1973).
Ott said there’s clear evidence that regular exposure to full-spectrum light is critically important for human health and well-being. It’s like an essential nutrient.
Our species evolved in natural surroundings under natural light, and indoor living in artificial light is one of many ways we’ve put ourselves seriously out of balance.
Even on cloudy days we benefit from natural light, and one of many reasons we often feel great during and after a hike is probably the extended light exposure.
Unfortunately there’s been a long-standing “campaign against the sun” among those who are concerned about skin cancer and the risk of damage to our skin.
Yes, such concerns have some merit, as we definitely do have to protect our skin from too much direct exposure, especially in summer and at higher elevations.
But inadequate exposure is problematic as well. Without sufficient natural light our immune systems may be depressed, with potentially serious health consequences.
As I’ve mentioned in the past, a growing number of cancer experts now acknowledge the importance of regular “unprotected” exposure to the sun (although Ott would say they greatly underestimate how much is needed).
Hiking is an excellent way to get sizable doses of full-spectrum light – as are other outdoor activities. Another good solution in any season is taking frequent walks.
-- Charlie Cook