Vitamin D: Vital Role in Your Health
Researchers conclude the "sunshine vitamin" is good medicine.
Here Comes the Sun continued...
But before you grab the beach towel and head for the seashore, keep in mind
that particularly in the higher northern latitudes, vitamin D levels can be
problematic. If you live above 40 degrees north latitude -- north of
Philadelphia, for example, or Denver -- you won't make much of any vitamin D in
A study at the University of Maine monitored vitamin D levels in 23 girls
(ages 10-13, all residents of Bangor, Maine). In findings presented at the
American Society for Bone and Mineral Research last September (2003), nearly
half of these girls had insufficient levels of vitamin D in their blood in
March, the time of year when levels tend to be lowest due to decreases in
sunlight exposure during the winter.
"I was surprised by some of our findings," Sullivan tells WebMD.
"These were healthy, active, light-skinned girls who spent a lot of time
outdoors. They were eating well-balanced diets, and many were milk drinkers. So
if anyone was going to have normal vitamin D status, you'd think it would be
them. But their levels were quite low by March. We're in central Maine at about
latitude 44 degrees north, and we don't make vitamin D in our skin for five
months a year -- between November and March."
That kind of sun scarcity can take its toll on human health. "There is
some striking evidence that as you go farther north, the incidence of certain
kinds of cancer increases," says Sullivan. "There is more prostate and
colon cancer in the north than in those who live closer to the
The correlation is similar for multiple sclerosis. Research has shown the
immune disorder is more common in areas with fewer hours of sunlight. For
example, multiple sclerosis is more common in Canada and the northern states of
the U.S. than in the southern states.
The Perils of Sun Worshiping
The sun isn't all good, of course. As any dermatologist will eagerly tell
you, too much sun could risk a lot more than a bad sunburn. Routinely
overdosing on sunshine could translate into life threatening skin cancer. On
the other hand, if you're completely sun-phobic from sunrise to sunset, you may
pay the price in the amount of vitamin D your body produces, cautions Holick,
author of The UV Advantage.