Scientific Evidence Proves Sunlight Fights Cancer
The theory that solar ultraviolet radiation- and by extension, vitamin D, which
is produced when such radiation strikes your skin- is a potent cancer fighter
satisfies most, if not all, of the criteria of a 2009 paper by Dr. William
Grant, Ph.D., internationally recognized research scientist and vitamin D
Dr. Grant's research shows just how strong the evidence that sunlight fights
cancer really is. In it he has applied the criteria for causality, originally
suggested by Robert Koch to show that tuberculosis was caused by a bacterium
and further organized in recent times by A. Bradford Hill. The research
analyzes the case for vitamin D's cancer-fighting power by looking at the
well-known Hill criteria for examining causality in a biological system. The
Hill criteria look at:
1. Strength of association
2. Consistency (repeated observation)
3. Specificity (one agent, one result)
4. Temporality (exposure precedes effect)
5. Biological gradient (dose-response relation)
6. Plausibility (e.g., mechanisms)
7. Coherency (no serious conflict with the generally known facts of the natural
history and biology of the disease)
8. Experimental verification (randomized, controlled trial)
9. Analogy with other causal relationships .
This approach was used to evaluate whether the association between sunlight and
decreased cancer rates can be considered causal, and after he applied the
evidence, he found that the theory satisfied most, if not all, of the Hill
criteria (the nine-step system listed above). There have also been numerous
studies that speak to the power of sunlight in reducing your risk of cancer.
From a scientific point of view, therefore, vitamin D reduces the risk of many
forms of cancer and increases survival rates once cancer reaches a detectable
stage. However, public policy often lags behind scientific research. It is to
be hoped that the acceptance of the beneficial nature of vitamin D in reducing
the risk of cancer and many other diseases will not have too much longer to
wait. It is encouraging that the National Academy of Sciences' Institute of
Medicine is currently embarking on a two-year study of vitamin D, and is
expected to issue a report in 2010.
Other research conducted by Dr. Grant found that about 30 percent of cancer
deaths (which amounts to 2 million worldwide and 200,000 in the United States)
could be prevented each year with higher levels of vitamin D.
Vitamin D Has A Protective Effect Against Cancer In Several Ways, Including:
• Increasing the self-destruction of mutated cells (which, if allowed to
replicate, could lead to cancer)
• Reducing the spread and reproduction of cancer cells
• Causing cells to become differentiated (cancer cells often lack
• Reducing the growth of new blood vessels from pre-existing ones, which is a
step in the transition of dormant tumors turning cancerous
Comments And Recommendations From Dr. Joseph Mercola (Mercola.Com) :
In the last few years the evidence has been pouring in that sunlight fights
cancer by producing vitamin D in your skin. Yet, public health officials have
been shuffling their feet when it comes to putting the evidence into action. If
health officials would simply recommend that you get some sensible sun
exposure, or supplement with oral vitamin D3 if you can't get out into the sun,
there could be major advances made in the fight against cancer. In short, your
risk of cancer could be cut in half. This is according to a large-scale,
randomized, placebo-controlled study that looked at almost 1,200 women, aged 55
and older, over the course of four years. Those in a group that was given
supplemental calcium and vitamin D had a 60 percent lower risk for all cancers
than those who received a placebo.
And for those who already have cancer, I believe it is virtually criminal
malpractice, or at least gross medical negligence, to not optimize vitamin D
levels when treating someone with this disease. As Dr. Grant wrote in his
article: "From a scientific point of view, vitamin D reduces the risk of
developing many types of cancer and increases survival once cancer reaches the
The ideal way to optimize your vitamin D level is by exposing your skin to
appropriate amounts of sunlight on large areas of your skin. Unfortunately for
most of us there simply isn't enough sun exposure for nearly half of the year.
However, even when the sun is shining many of us are modern-day cavemen and
spend the majority of the day inside at work or in our home. Not many of us are
regularly out in the sun.
You typically need enough exposure to turn your skin the lightest shade of pink.
If you have enough skin exposed you will produce about 20,000 units of vitamin
D. Exposures any longer than turning your skin the lightest pink will not
produce any additional vitamin D and potentially lead to premature skin aging
and increase your risk of skin cancers.
Most of us struggle with vitamin D winters in which we may not be able to get
enough sun exposure during certain parts of the year. In that case, I also
advise using a safe tanning bed (one that has the harmful emissions shielded) to have your own body produce vitamin D naturally.
A third option is taking a high-quality vitamin D supplement. The most important
thing to keep in mind if you opt for oral supplementation is that you only want
to supplement with natural vitamin D3 (cholecalciferol), which is human vitamin
D. Do NOT use the synthetic and highly inferior vitamin D2.
For those in the winter with no or very limited exposure to sunshine,
4,000-5,000 units per day is appropriate for most adults. If you are very heavy
you may need to double that dose, and for children the dose can be half that.
When supplementing, make sure you have your levels monitored to make sure your
levels are in the therapeutic range. For an in-depth explanation of what you
MUST know before you get tested, please read my updated article Test Values and
Treatment for Vitamin D Deficiency. If you live in the U.S. please be sure and
use Lab Corp. Quest labs is not as accurate and you will likely need to
multiply your results by 0.6 to give you a more accurate measurement of your
true vitamin D levels.