Let the Sun Shine
By Joel Stonington
Tired of spending your entire summer
in the shadows? Some scientists are now saying that a moderate
amount of sunshine is good for you, and shunning it altogether
could actually increase your risk of cancer.
The human body has a love-hate
relationship with the sun’s ultraviolet rays, Celeste Biever
reports in New Scientist (Aug. 9, 2003). Though it’s widely
known that UV radiation is linked to skin cancer, it’s also
one of our two main sources of vitamin D. (The other is a diet
rich in dairy products and certain oily fish.) It’s long
been understood that vitamin D helps us absorb calcium, and in
recent decades researchers have begun to think it may also block
or at least hinder the runaway cell growth associated with cancer.
The evidence intrigues some cancer
researchers, who go so far as to suggest that vitamin D-based
treatments might be used someday to slow many common forms of
the disease, including cancer of the colon, prostate, breast,
lung and skin. And if more vitamin D somehow helps to control
cancer growth, does less vitamin D leave us vulnerable to it?
At least one scientist thinks that might be the case.
Regional underexposure
to the sun
During the 1990s, William Grant, a NASA physicist studying atmospheric
ozone, noticed that cancer death rates were higher in the Northeastern
United States than is some other regions of the country. Many
assumed that a fatty diet was the culprit, but Grant’s work
pointed to another factor. While fat intake appeared to vary 10
to 20 percent between the Northeast and Southwest, he saw that
cancer incidence between these regions varied by a staggering
150 percent. Diet alone seemed unlikely to account for so big
a difference. The real cause? Grant suggests that it may be a
lack of vitamin D, tied to a regional underexposure to UV rays.
Grant based his case on a compelling
correlation. He found that death rates for 13 common cancers appeared
to be higher in places where people tend to get less UV exposure.
In other words, people in the sunny Southwest actually seemed
less likely to die from these forms of cancer than people in the
often overcast Northeast. He went on to estimate that at least
23,600 Americans die annually from cancer tied to a lack of sunshine,
compared to 9,800 from skin cancer. When his study was attacked
on several grounds, Grant went back and revised his figures –
upward. His new analysis suggested that as many as 40,000 die
each year from the apparent cancer-causing effects of sunlight
deprivation.
Most mainstream scientists still
aren’t buying it. Many are worried that Americans will take
sun worship too far. “People who sun themselves on the beach
are not at risk of vitamin D deficiency – they are at risk
of skin cancer,” Rebecca Mason, a physiologist at the University
of Sydney in Australia, told New Scientist.
Whatever the facts may be, no one
is recommending long hours of sunbathing in the buff. To get your
vitamin D from the sun, advocates recommend a few minutes two
or three times a week. To give you a rough idea, it’s said
that white people with medium-fair skin in Boston in July would
need a few midday sessions of 5 to 8 minutes, while African Americans
who rarely burn would need 20 to 30 minutes. (Blacks have more
of the UV-blocking pigment melanin in their skin, and thus absorb
vitamin D more slowly.)
The important point is that at
least one more public health message is no longer so clear-cut.
Moderation once again seems to be the key, or, as Ovid wrote in
Metamorphoses, “The middle way is safest.”
© Joel Stonington
Joel Stonington is
an online intern at Utne
magazine. He is currently traveling the country, spending
as much time in the sun as possible. Utne reprints the best articles
from over 2,000 alternative media sources, bringing you the latest
ideas and trends emerging in our culture – the best of the
alternative media.
