Catch the Sun's Rays

Surprising new facts about sun exposure.

November 26, 2010

Just when it seemed that sunlight was good for nothing but causing skin cancer and wrinkles, new research finds that sun exposure may protect against cancer. The controversial report in the Journal of the National Cancer Institute found that patients in the early stages of melanoma, the deadliest form of skin cancer, are significantly more likely to survive if they've had a history of sun worshipping.

Could sunlight really fight cancer? In the study, doctors measured sun exposure by interviewing melanoma patients and by looking at their skin changes at the start of the research. They then tracked the subjects' health for five years, leading to the contentious finding that sun damage equaled greater survival. In a second JNCI study, Scandinavian subjects who reported suffering frequent sunburns within the previous decade had up to 40 percent fewer incidences of non-Hodgkin's lymphoma than those who got less sun. Marianne Berwick, PhD, lead author of the melanoma study and director of cancer epidemiology and prevention at the University of New Mexico, speculates that vitamin D, which is made by the skin during sun exposure, may be what helps to limit the spread of cancer. Vitamin D also seems to be a factor in other benefits of sun exposure, such as preventing autoimmune diseases.


Berwick does not advocate getting sunburned, however: "There's still no question that increased sun exposure leads to melanoma. I would not advise throwing caution to the wind." She adds that for now, we should continue to limit sun exposurefive to 15 minutes three times a week without sunblock is more than sufficient. She expects an upcoming eight-year study to be more conclusive.

The benefits of sunlight are a topic that makes dermatologists bristle. James Spencer, MD, clinical professor of dermatology at Mount Sinai School of Medicine in New York, criticizes these studies, but admits that UV light is an effective weapon against certain diseases, just as chemotherapy works on cancer. "Basically, you're trying to poison the illness before the treatment poisons you," he explains. Read on for more of what both sides have to say about the sun's benefits.

Can You Cut Your Risks of Multiple Sclerosis?
The Bright Side

When researchers at the University of Tasmania surveyed people with and without MS for a 2003 study, they found that those who had higher levels of sun exposure (particularly at least an hour per day during the winter) from age six to 15 had a lower risk of developing the autoimmune disease. Scientists believe vitamin D may stop attack cells from damaging the immune system while it's still maturing, which is why they say sun exposure early in life is key. Separate studies have shown that sufficient vitamin D may also help prevent other autoimmune diseases, such as type 1 diabetes.

The Skeptic's Side
If the sun's rays do have any power over autoimmune disorders, this may be because UV light suppresses the body's immune system (autoimmune diseases result from an overactive immune system), says Howard Fein, MD, attending dermatologist at Harbor-UCLA Medical Center. This suppression, however, is what makes sun worshippers more vulnerable to a slew of other illnesses, including skin cancer.

Can It Relieve Pain?
The Bright Side

Let's hear it again for vitamin D: In a study published in 2003 by the Mayo Clinic, 93 percent of patients with unexplained muscle and skeletal pain were deficient in the nutrient. "Vitamin D is crucial for strong bones and muscles," says lead researcher Gregory Plotnikoff, MD, of the University of Minnesotaand the sun is a key source.

The Skeptic's Side
"Orange juice is fortified with vitamin D, as are milk and cereal," Spencer says. "If you get anything close to a normal diet, you should be just fine." You can also take a vitamin D supplement (200 to 600 IU daily is usually what's recommended).

Can It Make You Happier?
The Bright Side

The sun boosts brain levels of serotonin, the neurotransmitter associated with good mood. In fact, the sun-induced rush may be addictive. Scientists at Wake Forest University in North Carolina had regular tanning-booth patrons test out two tanning beds that looked and felt exactly alikeexcept that one emitted UV rays and the other didn't. When given the option to return to the bed of their choice, 92 percent of the subjects chose the one that radiated UV, adding they found it more relaxing.

The Skeptic's Side
Bruce Rabin, MD, medical director of the University of Pittsburgh Healthy Lifestyle Program, says that sun-related serotonin production happens simply when you see sunlight, which means that wearing an SPF 45 won't minimize the feel-good effect one bit.

The Bottom Line
More research on the benefits of sunlight needs to be done. But even if the pro-sun studies are right, dermatologists maintain that the vast majority of people meet their vitamin D quota without thinking about it. "Sunscreen use is going down, not up," Spencer says. "And most people get five to 10 minutes two to three times a weekthe amount prescribed by pro-sun expertsjust by running errands and walking across parking lots." So keep using that sunscreen: You need to use a product with an SPF 15 or higher, and you should reapply it every two hours during exposure to the sun.