Doctors Squabble Over Sunshine Vitamin

Is it any wonder so many people are confused about the sun? On the one hand, dermatologists have been issuing dire warnings for decades. They tell us that sun exposure causes wrinkles, age spots and skin cancer.
If we go out in the sun without slathering on the sunscreen we’ve been led to believe we’re living dangerously. No one is supposed to spend time in the midday sun (defined as any time between 10 am and 2 pm) unless they are well covered with protective clothing.
On the other hand, research has been mounting that sunshine prevents cancer. Numerous studies have demonstrated that cancers of the colon, breast, prostate and lung are less common among people who get some regular sun exposure. There is even research to suggest that a little sunlight may help against skin cancer.
Harvard professor, Edward Giovannucci, ScD, stirred up a hornet’s nest with his recent keynote speech to the American Association for Cancer Research. Dr. Giovannucci suggested that exposure to the sun might prevent 30 deaths from other cancers for every death caused by skin cancer.
To achieve this benefit, though, people may need over 1000 International Units (IUs) of vitamin D daily. The current recommendation is for only 400 IUs. Sunshine is important because it stimulates the production of vitamin D in the skin. It is possible to overdose with oral supplements, but the skin only makes as much as the body can use.
Unfortunately, many Americans do not get enough vitamin D. They spend most of their time inside. Even in the summer they may prefer to spend their time in air-conditioned comfort. If they do engage in outside activities they put on a high SPF sunscreen before they even go out the door. This dramatically reduces the amount of vitamin D the skin can make.
Is it possible to get the benefits of the sun without putting yourself at risk of premature aging or skin cancer? According to Michael Holick, MD, PhD, Professor of Medicine, Physiology and Biophysics at Boston University School of Medicine, sensible exposure is absolutely necessary for good health.
Vitamin D made in the skin circulates throughout the body. Tissues that need to use this compound as a hormone are capable of transforming it into the activated compound that seems to be responsible for its cancer-preventive properties. The form of vitamin D produced by sun-exposed skin may be more efficient for this purpose than oral supplements.
For those who would like to know more about the benefits of vitamin D and sensible sun exposure we offer a one-hour radio interview with Dr. Michael Holick. For a CD of this show, please send $15 in check or money order to Graedons’ People’s Pharmacy, No. CD-502, P. O. Box 52027, Durham, NC 27717-2027.
In addition to the anti-cancer benefits of vitamin D, a recent analysis (JAMA, May 11, 2005) reveals that this nutrient can help protect bones. Supplements of at least 800 IUs of vitamin D reduced the risk of hip fracture by 26 percent.
Although some dermatologists still maintain that people should stay out of the sun at all times, there is a growing recognition that prudent exposure to the sun may have a wide variety of health benefits.