Excerpt: 'UV Advantage'

June 30, 2004 -- With skin care doctors advising that you avoid excessive exposure to rays of light, in this excerpt from UV Advantage Dr. Michael Holick and Mark Jenkins describe the health benefits of spending time in the sunshine

Preface

It happened again the other day. I was in a hotel elevator and overheard a woman telling her companion how much she loved to be in the sun but she couldn't anymore because "it would kill her." It's the kind of thing I hear all the time, and it is what inspired me to write this book.

My goal is to help put society's attitude toward sunlight into proper perspective. I've been researching this subject for many years, and institutions from NASA to the National Zoo have come to me for advice. I've successfully treated a variety of serious diseases with exposure to the kind of radiation that's in sunlight (UVB), including osteoporosis, osteomalacia, high blood pressure, and psoriasis. Results of my studies have been published in major scientific and medical journals.

Most people have taken my support of moderate sun exposure to mean I advocate tanning. Not true. Do I lie out in the sun for hours at a time or frequent tanning salons? No. Do I go out in strong sunshine without a sunscreen on, and does my skin get tanned? Yes. Why? Because I recognize that my body needs a certain amount of sun exposure to be healthy. Do I put sunscreen on after a certain amount of time? Yes. Why? Because I understand that there are risks as well as benefits associated with being in the sun. I recently ran into that poster boy for tanning, George Hamilton. When he found out I was an advocate of sun exposure, he jokingly commented that my skin was so pale he could see his reflection in it!

I am advocating common sense, something often in short supply in modern America's approach to health. I also respect your right to do something that may make you look and feel better. I believe I can help you make choices that will pursue this goal in a healthier, more effective way. Our society doesn't seem to believe in a happy medium, only in extremes.

Do not be afraid-you are not going to die just because you go out in the sun. Indeed, the UVB radiation in sunlight is essential for good health. The notion that we have to protect ourselves from the sun all the time is misguided and unhealthy. This sun phobia explains why so many people are suffering from conditions related to sun deprivation.

Part of the problem is that our national health leaders have lost faith in the public's ability to make informed decisions about health. Their attitude seems to be: We can't trust the public to be judicious in its attitude toward sun exposure, so let's tell people they shouldn't spend any time in the sun. The problem with this presumptuous approach is that eliminating sun exposure is out-and-out unhealthy. Lack of sunlight is associated with a host of conditions from colon, breast, prostate, and ovarian cancer to heart disease, high blood pressure, Type 1 diabetes, multiple sclerosis, and depression. Many of these policymakers are out of touch with new research and are unfamiliar with the growing body of evidence that shows how important sunlight is to human health.

Your overall well-being depends in part on developing an appropriate relationship with the sun. However, it can be a challenge to get the kind of information you need to establish such a relationship. The main purpose of this book is to provide you with an unbiased understanding of the issues at hand. Equipped with this information, you will be able to make your own decision about what your relationship to the sun should be. You, too, can learn to use sunlight for health.

Chapter One: The Facts of Light

Why you need sunlight, and how you got conned into thinking it was bad for you

It was the summer of 1997 and for months my staff and I had been studying the vitamin D status of a random group of people living in the Boston area. As Director of the General Clinical Research Center and Professor of Medicine, Dermatology, Physiology, and Biophysics at Boston University Medical Center, I had designed and was leading this study. I was sitting in my office when the results came in. Although I had a strong suspicion by that time of what the study would reveal, the actual numbers were staggering. Fully 42 percent of the people we studied were vitamin D deficient.

My study, which was accepted for publication in Lancet (only one in a hundred papers submitted to this renowned journal are published), confirmed what most scientists in the field believe. That is, there is an epidemic of vitamin D deficiency in the United States and much of the Western world. Some have called this a "silent epidemic" because, although the consequences of vitamin D deficiency are profound, there are often no obvious symptoms.

What is the cause of this "silent epidemic"? In part, it is the result of very few people these days eating enough foods rich in vitamin D-mostly "oily" fish such as salmon and mackerel. Also, most Americans do not compensate for a diet poor in vitamin D by following recommendations to drink enough vitamin D-fortified milk or to take nutritional supplements. (Milk usually contains far less vitamin D than the FDA approves of.)

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. (My studies have shown that SPF 8 reduces vitamin D production by 97.5 percent and SPF 15 reduces it by 99.9 percent).

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 dependant on sunshine for life and health. Sunlight is the fuel that enables your body to manufacture vitamin D. When you block out sunlight with sunscreens and head-to-toe clothing, you stop that supply of fuel and your body can't make enough vitamin D.

Why does this matter? The short answer is that the benefits of vitamin D on human health are many, varied, and profound. We'll take a thorough look at these benefits in chapter 4. Suffice it to say that in some respected medical circles, sunlight is being described as a "wonder drug." It can provide "immunity" against one of the most devastating diseases around, including heart attack, stroke, osteoporosis, and certain of the most deadly internal cancers.

The statistics speak volumes. Some researchers, notably Dr. William Grant, have proven that, in America, increased sun exposure would result in 185,000 fewer cases of internal cancers every year and 30,000 fewer deaths (specifically cancers of the breast, ovaries, colon, prostate, bladder, uterus, esophagus, rectum, and stomach). 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 or on a tanning bed 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, one of the main causes of death and disability among senior citizens.

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.

Those who heed warnings to avoid the sun because "sunlight is dangerous" (whom I refer to as "sun-phobes") are robbed of the life-sustaining benefits of sun exposure-and this idea denies basic evolutionary science.

In the Beginning …

From the beginning of recorded time, humans have worshipped the sun for its therapeutic properties. This can be seen in cave paintings that show that exposure to sunlight was necessary for life and good health. Medical practitioners reported the benefits of sun exposure on heart health 6,000 years ago in the time of the ancient Egyptian pharaohs Ramses and Akhenaten. Sun therapy was also praised by the legendary Hippocrates (creator of the Hippocratic Oath) and the doctors of bygone Rome and Arabia. The Egyptians, Mesopotamians, and Greeks all had sun deities, and the influence of the sun in religious belief also appears in Zoroastrianism, Mithraism, Roman religion, Hinduism, Buddhism, and among the Druids of England, the Aztecs of Mexico, the Incas of Peru, and many Native American groups.That ancient peoples instinctively understood that sunshine was good for them is not surprising. Humans have depended on sunlight to sustain life and health since our ancestors slithered out of the primordial ooze.

Without the calcium-rich environment of the bubbling saline oceans in which life evolved-and from which we could absorb calcium right into our primitive skeletons-our creepy-crawling ancestors got their calcium on land by eating plants.

The main job of calcium is to build bones, and these ancient relatives of ours developed a system of absorbing the calcium through diet into the bones. This chemical process required the presence of vitamin D, which was made in the skin when it was exposed to sunlight.

Fast-forward a couple million years, and Homo sapiens were still using sunlight to make the vitamin D needed to regulate the calcium necessary for bone health. Early humans lived near the equator where sunlight is plentiful, and they developed dark, melanin-rich skins that protected them against sunburn but still "let in" enough sunlight to make vitamin D. As humans started to migrate away from the equator to regions where sunlight is less intense, and where for several months of the year the sun isn't strong enough for the human body to make vitamin D, skin got less pigmented so it would more effectively "let in" the sun when it was available. The farther north humans migrated, the fairer their skin became to make use of available sunlight. Eventually humans couldn't migrate any farther north because there wasn't enough sun to make the vitamin D needed to survive. Then something fascinating happened-humans developed the means to harvest the seas for vitamin D-rich fish and mammals of the sort still traditionally eaten by Eskimos and Scandinavians and that enable people to live in climates with very little sunlight.

Even today, people with fair skin don't require much exposure to sunlight to make enough vitamin D to be healthy, and people with dark skin are naturally well protected against sunburn. Conversely, people with fair skin get sunburned quite easily and may be susceptible to skin cancer, whereas dark-complected people more easily become vitamin D deficient when living in northern climates.Although this is a very simplistic explanation for why humans need sunlight for health and life, it should put to rest the notion that sunlight is something humans must fear. Sunlight is necessary for human survival!

Sunlight 101

To fully understand the pros and cons of sun exposure, you need to know what's going on "up there" and how it affects you "down here."Sunlight consists of a mixture of electromagnetic radiation of various wavelengths, from the longest, called infrared, through red, orange, yellow, green, blue, indigo and violet, to the shortest in wavelength, called ultraviolet.Ultraviolet, or UV radiation, consists of UVA, UVB, and UVC. UVC is completely absorbed by the atmosphere. UVA and UVB reach Earth's surface but have different effects on your body. UVA radiation causes wrinkles and in extremely high doses may be responsible for melanomas.

UVB is the form of radiation that reddens skin and that may be responsible, over the long term, for non-melanoma skin cancer. When UVB causes sunburns, it may contribute to melanoma. UVB is also the form of radiation that starts the reaction in skin that stimulates the production of vitamin D.

Until recently, most sunscreens only blocked UVB radiation, which may have precipitated the rise of melanoma in the United States and other Western cultures. That's because sunscreens that block out only the burning UVB radiation enable people to stay out in the sun for unlimited periods of time during which they are not protected against UVA radiation. Without any sunscreen at all, people would not have been able to stay out in the sun long enough to receive the dosage of UVA necessary to cause melanoma.Thankfully, researchers have now developed "broad spectrum" sunscreens, which protect against both UVA and UVB radiation.The level of UV radiation that reaches the Earth varies depending on several factors, including the following:

Stratospheric ozone. The ozone layer absorbs most of the sun's radiation, but how much it absorbs depends on what time of year it is and certain other natural phenomena. As a whole, the ozone layer has thinned due to industrial pollution and now-banned substances previously emitted by refrigerants and certain consumer products such as hairspray.

Time of day. UV levels are at their most intense at noontime, when the sun is at its highest point in the sky. When the sun is at its highest point, the UV radiation has the least distance to travel through the atmosphere to earth. Contrarily, the sun's radiation must pass through the atmosphere at a greater angle during the early morning and late afternoon, and therefore UV intensity is greatly diminished at those times.

Time of year. The angle of the sun changes with the seasons. This causes the intensity of the UV radiation to vary as well. UV intensity is greatest during the summer months.

Latitude. The sun's radiation is most intense at the equator where the sun is directly overhead and the radiation from it has to travel the shortest distance through the earth's ozone atmosphere. Therefore, at the equator, more UV radiation reaches the earth's surface from the sun.

At higher latitudes, the sun is lower in the sky and UV radiation has to travel a greater distance through thicker ozone to reach the earth's surface. This makes the UV radiation in middle and high latitudes less intense.

Altitude. UV radiation is more intense at higher altitudes because there is less atmosphere to absorb it. When you are at higher altitudes, therefore, you are at greater risk of overexposure.

Weather conditions. The more clouds there are, the less UV radiation can penetrate to the earth's surface. However, UV can still penetrate cloud cover, which explains why you can still get sunburned on a hazy summer's day.

Reflection. Certain surfaces reflect UV radiation and increase its intensity even in shaded areas. Such surfaces include snow, sand, or water.

Science and Sunlight

When modern science began investigating the connection between sunlight and health, it was initially believed that the health benefits of sunlight were the result of the warmth generated by the sun. It was Sir Everhard Home, in the late 1700s and early 1800s, who deduced that it wasn't the heat of the sun's radiation but rather the occurrence of a chemical effect on the body caused by the sun that produced sunburn. Home also showed that dark-skinned people had a natural resistance to sunburn. In the 1820s, a Polish doctor named Jedrzej Sniadecki first observed that children who lived in the city of Warsaw had a much higher prevalence of rickets than youngsters who lived in the Polish countryside. Dr. Sniadecki thought it was probably the lack of sunshine in the cramped confines of Warsaw that was to blame for this widespread condition. Sniadecki was able to successfully treat the afflicted city kids by taking them into the countryside for sun exposure, which began a long-standing tradition for treating this condition. Floating Hospital in Boston, now a modern multistoried structure, got its name because it was originally a large boat that, in the summertime, took children with rickets into Boston Harbor to be bathed in sunshine. Although the exact relationship between sunlight and bone development was not yet understood, a health movement was pioneered by Arnold Rikli at the end of the 1800s with this motto: "Water works wonders, air can do even more, but light works best of all."

By the beginning of the twentieth century, scientists had determined that it was the UV radiation in sunlight that stimulated the production of vitamin D in the human body. They determined that this was important for a variety of health reasons. Based on findings that the vitamin D created by sun exposure improved bone health, the dairy industries of Europe and the United States started fortifying milk with vitamin D. A craze was under way, and vitamin D fortification was being touted by the manufacturers of products as varied as Bond Bread, Rickter's Hot Dogs, Twang Soda, and even Schlitz Beer.

The first few decades of the twentieth century were the heyday of photobiology and heliotherapy. Photobiology is a branch of science that investigates the effect of natural and artificial radiation on all life forms; heliotherapy focuses on the sun's abilities to heal the sick. Photobiologists and heliotherapists were credited with developing effective treatments for rickets, tuberculosis, and psoriasis.

Hospitals all over Europe and the United States had built solariums and balconies so they could offer their patients a pleasant place to enjoy the sun's healing rays. In addition, a photobiologist had won the Nobel Prize for Medicine. However, the tide was about to change.

Frightening People Out of the Daylight

So what happened? How did we reach a point in our history when sun became something to be feared instead of worshipped? Shunned instead of desired? The simple answer lies in the fact that there are many billions of dollars to be made in emphasizing the only major medical downside of sun exposure (non-melanoma skin cancer) and not much money to be made in promoting the sun's many benefits.

Medicine has long known that, despite all the sun's benefits, a health downside of sun exposure is non-melanoma skin cancer. In the 1920s, it was recognized that farmers in Europe developed skin cancer on their most sun-exposed areas-their ears, face, nose, and backs of their hands. In 1941, the first issue of the Journal of Cancer put the issue in perfect perspective, stating that an increased risk of non-melanoma skin cancer was one of the prices to be paid for a decreased risk of cancer of the prostate, breast, and colon. Unfortunately, in the past quarter century, the relationship between sunlight and skin cancer has been blown out of proportion. The major culprits are the cosmetic wing of the pharmaceutical industry and some dermatologists.

In the 1960s and 1970s, as the leisure culture expanded and people were spending more time outdoors, the "cosme-ceutical" industry developed anti-sunburn creams that gave the user a false sense of security and encouraged excessive sun exposure. These products began making extraordinary amounts of money for the companies.

Although the products were initially introduced to prevent sunburn, they soon were being cannily marketed to prevent skin cancer. There is an important role for modern sunscreens in preventing skin cancer, and people should control sun exposure in the same way they watch how much salt, sugar, and fat they eat and how much alcohol they drink. However, the sophisticated and aggressive "educational" campaigns funded by the cosme-ceutical industry have created an anti-sunshine hysteria that is detrimental to our health because it converts people into sun-phobes by convincing them that no amount of sun exposure is safe.

So desperate is the anti-sun lobby to convince you of the dangers of the sun so that you will buy its products year-round, its representatives will tell you with a straight face that if it's February in Boston and you're planning to walk to the corner store to buy a quart of milk or sit outside on your lunch break, you should wear sunscreen. This is wrong-headed and alarmist. Even on the sunniest February day, the sun isn't strong enough in New England or New York to increase your risk of skin cancer significantly. This is but one example of the kinds of inaccurate information the anti-sun lobby puts out to alarm people. In so doing, it convinces people of the need for its products and services.

The scare tactics of the cosme-ceutical industry have been embraced by most of the dermatology profession. These groups have worked in concert and have frightened the daylights out of people-or, to put it more accurately, frightened people out of the daylight. It has turned them into sun-phobes.

To put the dangers of skin cancer in context, it's worthwhile looking at some statistics. Non-melanoma skin cancer, which may be caused by long-term sun exposure, has an extremely low death rate.

Fewer than half of 1 percent of people who develop non-melanoma skin cancer die; non-melanoma skin cancer claims 1,200 lives a year in the United States. Compare that with diseases that can be prevented by regular sun exposure. Colon and breast cancers, which may be prevented by regular sun exposure, have mortality rates of 20 to 65 percent and kill 138,000 Americans annually. Osteoporosis, a bone disease that can be mitigated by regular sun exposure, is endemic, affecting 25 million Americans. Every year, 1.5 million Americans with osteoporosis suffer bone fractures, which can be fatal when the person is elderly. Non-melanoma skin cancer is not something to be taken lightly, and I would never minimize its effects on sufferers, but in public health terms, it is relatively unimportant when compared with a host of killer diseases that can be prevented by regular, moderate sun exposure.

What about melanoma? This is an important question. Though rare, melanomas are by far the most dangerous form of skin cancer, and, if left untreated, they are often fatal. Eighty percent of all skin cancer fatalities are attributed to this type of cancer. However-and this is a critical point-there is no credible scientific evidence that moderate sun exposure causes melanomas. In chapter 2, I will clear up the confusion surrounding the relationship between sun exposure and skin cancer, confusion that the media doesn't seem able to unravel and the anti-sun lobby has a vested interest in maintaining.

The anti-sun lobby also plays on people's fear of developing wrinkles-a growing concern in our youth-obsessed culture. It's true that sun exposure causes the skin to age prematurely, but it is possible to take advantage of the benefits of sun exposure while minimizing wrinkles. Interestingly, the type of sunscreens used in the 1960s probably predisposed people who sunbathed during that era to wrinkles. I'll take a closer look at this issue in chapter 3.So why has no one stood up to the anti-sun lobby and said, "Hey, wait a minute, for too long you've exaggerated the dangers of sun exposure and ignored the fact that human beings need sunlight to live"? Well, I have!

The problem is, whenever anyone challenges the anti-sun coalition doctrine that sun exposure does nothing but cause skin cancer and wrinkles-usually by publishing a new study that demonstrates a positive link between sunlight and disease prevention-this news is drowned out by another well-funded round of disinformation about the hazards of sun exposure. The bibliography at the end of the book lists many of the published studies that show the beneficial association between the vitamin D you get from sunlight and many areas of health.

It's difficult to get the facts out because there is no sun lobby. Sunshine is free, after all, so there's not much money to be made extolling its virtues. The indoor tanning industry has tried to step up to the plate (modern indoor tanning equipment provides many of the same benefits as natural sun exposure). However, the indoor tanning industry consists of numerous small, independent companies that could hardly be considered unified. The industry's trade organization, the Indoor Tanning Association, is a pauper compared with the wealthy princes representing the cosme-ceutical industry and the dermatology profession, and it has trouble making itself heard over the anti-sun din.

It doesn't help that media outlets have little appetite for "feel good" health stories-they believe their readers are more engaged by stories about what's going to kill them rather than what will make them feel better. Of course, it's also important to understand that newspaper editors and TV producers are busy men and women. When slickly packaged information about the "hazards of sun exposure" lands on their desks and no one contests this information, they are inclined to publish it verbatim to fill column inches and airtime. Often the "educational" material put out by the anti-sun lobby has been endorsed by eminent-sounding professionals and organizations.

Increasing numbers of studies are confirming the link between vitamin D and good health, however, and attitudes are beginning to change. More important, in the past few years there has been a breakthrough in our understanding of why sun exposure benefits health in so many ways, something that was not fully comprehended until recently. This breakthrough has forced people to take a closer look at the benefits of sun exposure. I am proud to say that I have been at the forefront of this research.

Excerpted from The UV Advantage by Dr. Michael Holick, copy; 2004. This excerpt can't be reprinted without permission from the publisher.

Get information on sun exposure from the American Cancer Society and the American Academy of Dermatology.Click Here.

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