The bright — and dark — side of the sun

By Cynthia Billhartz Gregorian, St. Louis Post-Dispatch
Posted May 21, 2012, at 3:26 p.m.

Memorial Day weekend, the unofficial start of summer, is nearing and the sun’s rays will be at their strongest.

Some people will head for the nearest pool, where they’ll roast themselves golden brown. They’ll also get a dose of vitamin D that will sustain them for the summer.

Others will slather on sunscreen, wear wide-brimmed hats and take vitamin supplements.

Our relationship with the sun ranges from phobic to “tanorexic,” a term coined for people who seem addicted to the sun.

The American Academy of Dermatology recommends leaning toward the phobic. The academy maintains there is no safe amount of sun when it comes to skin cancer risk.

Not for adults, and especially not for children.

Skin cancer is the most common form of cancer in the United States. The Skin Cancer Foundation estimates that one in five people will be diagnosed with skin cancer in their lifetime; more than 2 million people are diagnosed each year. Between 40 percent and 50 percent of Americans who live to age 65 will have it at least once.

Health experts believe children’s skin is particularly vulnerable. According to the U.S. Centers for Disease Control and Prevention, a few serious sunburns during childhood can increase the risk of skin cancer later.

“We do think kids are more vulnerable, and animal models of melanoma agree with that,” said Dr. Lynn Cornelius, chief of dermatology at Washington University.

While most health experts agree that prolonged exposure to ultraviolet rays is bad, some think we’ve gone overboard with protecting ourselves from the sun.

Before vitamin supplements and fortified foods, the sun was the only source of vitamin D. The vitamin promotes calcium absorption, which is essential for bone growth.

One of the most outspoken critics of the no-sun approach is Dr. Michael F. Holick, an endocrinologist and professor of biophysics and physiology at Boston University.

In his 2009 book, “The Vitamin D Solution,” Holick argues that sun phobia is causing an epidemic of vitamin D deficiency. He recommends about 15-30 minutes of sun exposure on the arms and legs two to three times a week.

His ideas are so controversial that he was fired from Boston University’s department of dermatology in 2004.

Some health experts, including Holick, believe that vitamin D deficiencies are contributing to a host of health problems beyond osteoporosis, including cardiovascular disease, autoimmune disorders and even cancer.

Dr. George Griffing, an endocrinologist and professor of internal medicine at St. Louis University Medical School, won’t go that far, but he does agree that the sun is a good source of vitamin D.

In the summer, Griffing suggests spending 10 to 20 minutes a day outdoors wearing short sleeves, a hat and no sunscreen.

Dark-skinned people have to be in the sun about twice as long to get the same benefit, he said. But he estimated that only about 20 percent of people are vitamin D deficient.

Some estimates have put that rate as high as 80 percent. Regardless, most people don’t need expensive testing to determine their vitamin D levels, Griffing said. They can get enough of the vitamin by taking supplements and consuming fortified foods and milk. Oily species of fish, such as tuna and salmon, also contain vitamin D.

But for people who have had bariatric surgery and are having a difficult time absorbing vitamin D from fortified foods and supplements, the sun is a simple and effective option, Griffing said.

Cornelius prefers supplements.

“We don’t like to advocate UV exposure as a way to get vitamin D,” she said. “Why would you expose yourself to the sun and its carcinogens when you don’t have to?”

©2012 the St. Louis Post-Dispatch

Distributed by MCT Information Services

http://bangordailynews.com/2012/05/21/health/the-bright-and-dark-side-of-the-sun/ printed on July 31, 2014