June 14, 2004
Summer is here.
We have all been warned about the dangers of skin cancer and too
much sun, but the sun is not all bad!
How could the sun possibly be
good for a person's health? Even help FIGHT cancer?
"How can sunlight
also protect against cancer? The answer lies in a vitamin that
may play a role in controlling the production of cells - vitamin
D. Vitamin D is manufactured in the skin when it is exposed to
sunlight and it is this vitamin that may have a protective effect
against certain cancers by preventing the overproduction of cells."
Vitamin D: "...this
vitamin that may have a protective effect against certain cancers..."
In addition, "A
diet rich in vitamin D may reduce the risk of developing rheumatoid
arthritis and multiple sclerosis. Two studies involving more than
200,000 American women have highlighted the vitamin's benefits....Both
conditions are thought to occur when the body's immune system
turns against itself. Vitamin D may work by calming overactive
immune cells, speculates Kenneth Saag from the University of Alabama,
Birmingham, who led the arthritis study.... Vitamin D is a steroid
hormone that helps the body absorb and retain calcium. Too much
can be toxic, while too little causes brittle bones."
Yes, Vitamin D. Before
you get too excited and trade your sun screen for hours of unprotected
"Vitamin D is called
the 'sunshine vitamin' because it is formed in the skin by the
action of ultraviolet rays from the sun. For fair skinned individuals,
15 minutes of sunlight will produce enough Vitamin D to last for
several days, even when wearing light clothing. However, it takes
3 hours or more for this to happen with dark-skinned people."
Times ranging from 15
minutes to 3 hours? (Please note that these times are not recommended
for everyday. Just a few times a week is plenty.) Why such a broad
have different amounts of melanin in their skin. Those with a
Northern European background tend to have less melanin and be
rather pale, whereas people with dark brown or black skin, like
many people from Africa, have more. Based on these differences,
dermatologists have come up with six skin types, ranging
from a Type I (fair skin, blonde or red hair, and always burns
in the sun) to a Type VI (black skin and usually
doesn't get sunburned). People who are a Type V or VI have more
natural protection against the sun than those who are a Type I
or II, but that doesn't mean they should ignore warnings about
Even those with Type
V or VI need to be careful. Three or more hours of sun exposure
is needed if there are no other sources of Vitamin D (like from
one's diet). Even so, this is the total amount of time needed
for several days worth of Vitamin D. A total of about forty-five
minutes a day in the sun: walking to and from school, waiting
for the school bus, driving with the windows rolled down, walking
between classes, and the list goes on. It is not hard to get 3
hours of sun over the course of a few days. For those who need
only fifteen minutes, it seems as though it would be difficult
not to get more.
and legitimate fear of skin cancer -- sunscreen blocks D production
-- limit how much Americans produce even in summer. Winter sunlight
is not intense enough at most U.S. latitudes to produce any, Holick
So how much is enough?
"Holick and others
argue that instead of the 200 to 600 international
units a day that current recommendations suggest, most people
should be getting at least 1,000 units a day. In a controversial
new book, 'The UV Advantage,' Holick recommends exposing the hands,
face, arms and legs to the sun for five to 15 minutes a day a
few days a week, which he says would be enough to generate that
amount without increasing the risk for skin cancer. Many people
are not getting even that amount of sun exposure on a regular
basis, Holick and others say. 'There's no question that chronic,
excessive exposure to sunlight and sunburning incidents markedly
increases your risk for skin cancer. But there's little evidence
out there that if you practice safe
sun exposure, it would increase your risk for skin cancer or wrinkling,'
"To get a good idea
of the effects of sunlight, look at your parents' skin and see
how different it is from yours. Much of that difference is due
to sun exposure and only a small part is due to the fact that
your folks are actually older than you are. In the worst-case
scenario, too much sun can cause skin cancer, lead to problems
with your eyes, or weaken your immune system, making it harder
for you to fight off diseases. Skin cancer is epidemic in the
United States. Although the numbers of new cases of many other
types of cancer are falling or leveling off, melanoma, the most
serious (and most frequently fatal) type of skin cancer, is the
fastest-growing type of tumor in the United States in terms of
new cases. In fact, dermatologists are seeing patients in their
twenties with skin cancer these days - in the past,
skin cancer mostly affected people in
their fifties or older."
The need is still there
to be safe in the sun.
men are more likely than women to develop skin cancer, women under
the age of 40 comprise the fastest growing group of skin cancer
There is such a thing
as too much of a good thing.
"There is a high
health risk associated with consuming too much vitamin D. Vitamin
D toxicity can cause nausea,
vomiting, poor appetite, constipation, weakness, and weight loss.
It can also raise blood levels of calcium, causing mental status
changes such as confusion. High blood levels of calcium also can
cause heart rhythm abnormalities. Calcinosis, the deposition of
calcium and phosphate in soft tissues like the kidney can be caused
by vitamin D toxicity. Consuming too much vitamin D through diet
alone is not likely unless you routinely consume large amounts
of cod liver oil. It is much more likely to occur from high intakes
of vitamin D in supplements. The Food and Nutrition Board of the
Institute of Medicine considers an intake of 25 mcg (1,000 IU)
for infants up to 12 months of age and 50 mcg (2,000 IU) for children,
adults, pregnant, and lactating women to be the tolerable upper
intake level (UL). A daily intake above the UL increases the risk
adverse health effects and is not advised.
supplements commonly provide 200-400 IU of vitamin D daily. He
says a light-skinned person wearing a swimsuit at the beach will
have absorbed about 20,000 IU of vitamin D in the time it takes
their skin to get lightly pink...'The trick is getting just enough
sun to satisfy your body's vitamin D requirement, without damaging
the skin,' he says. 'It is difficult to believe that this kind
of limited exposure significantly increases a person's risk of
Questions of the Week:
Think about the life you lead, what type of skin you have, and
where you live. What is a healthy amount of sunlight for you?
How does this differ from what might be a healthy amount for someone
else? What do you need to do in order to work this healthy balance
into your busy life?
Please email me with any ideas or suggestions.
Note: Due to increasing amounts of SPAM sent to this account, please include "QOW" in the subject line when sending me email.
I look forward to reading
what you have to say.
Health Community Coordinator
Access Excellence @ the National Health Museum