Prevent Cancer With The
Sunshine and Vitamin D
that sizzled and fizzled, the evidence for Vitamin D's health
benefits is now strong and keeps growing. If it bears out, it
will challenge one of medicine's most fundamental beliefs: that
people need to coat themselves with sunscreen whenever they're
in the sun. Doing that may actually contribute to far more cancer
deaths than it prevents, some researchers think.
is D, nicknamed the "sunshine vitamin" because the
skin makes it from ultraviolet rays. Sunscreen blocks its production,
but dermatologists and health agencies have long preached that
such lotions are needed to prevent skin cancer. Now some scientists
are questioning that advice. The reason is that vitamin D increasingly
seems important for preventing and even treating many types
In the last
few years alone, dozens of separate studies found vitamin D
helped protect against lymphoma and cancers of the prostate,
lung and, ironically, the skin. The strongest evidence is for
A study published in the Archives of Internal Medicine on May
28, 2007, suggested that women who consume higher amounts of
calcium and vitamin D may have a lower risk of developing breast
cancer before menopause. The study followed more than 31,000
women aged 45 and older for 10 years. It found that intake of
calcium and vitamin D was moderately associated with a lower
risk of breast cancer before but not after menopause.
study released on May 15, 2008 found that women
with low levels of vitamin D may have a poorer prognosis than
those with sufficient vitamin D. The study by Toronto researchers
also found that women with too little of the vitamin had a greater
chance of recurrence and lower overall survival rates than those
with healthier amounts.
involved 512 women, aged 35 to 69, who were diagnosed with breast
cancer between 1989 and 1996. Their health was followed until
2007, on average for almost 12 years. The researchers found
that 37.5 per cent of the patients were vitamin D deficient
and 38.5 per cent had levels that were considered insufficient
for good bone health. Only 24 per cent had sufficient levels
of vitamin D in their blood.
say their study shows there is an association between vitamin
D levels and breast cancer outcome. They say it's too early
to tell whether vitamin D deficiency can cause the disease.
than two weeks later, another study suggested the cancer-fighting
properties of vitamin D may be not be universal. The study,
published in the Journal of the National Cancer Institute, found
that a higher level of vitamin D in men is not associated with
a lower risk of developing prostate cancer. And in some cases,
it may be linked to a higher risk of developing a more aggressive
form of the disease.
a study published in the June 9, 2008 issue of the Archives
of Internal Medicine found that men with low levels of vitamin
D may have an increased risk of heart attack. The study followed
the medical records and blood samples of 454 men who had non-fatal
heart attacks or fatal heart disease from January 1993 and January
2004. They compared the data from those men with records and
blood samples of 900 living men who had no history of cardiovascular
disease. The researchers also recorded diet and lifestyle factors.
found that after adjusting for several factors including
family history of heart trouble, body mass index, alcohol consumption,
physical activity and hypertension men with low levels
of vitamin D (less than 15 nanograms per millilitre of blood)
had a higher risk for developing heart disease than men with
sufficient levels of vitamin D (30 nanograms per millilitre
of blood or more).
Cannell, the executive director of the U.S. Vitamin D Council,
in 2006 published a study in the Journal of Epidemiology and
Infection suggesting among other things that children who are
exposed regularly to sunlight are less likely to catch colds
and respiratory infections. A separate 2006 study published
in the journal Science suggested that Vitamin D might boost
the body's production of naturally occurring antibiotics.
by the benefits the sunshine vitamin offers, many public health
officials are encouraging people to include vitamin D in their
diets as researchers continue to investigate how it helps the
aren't getting enough vitamin D. It's hard to do from food and
fortified milk alone, and supplements are problematic.
So the thinking
is this: Even if too much sun leads to skin cancer, which is
rarely deadly, too little sun may be worse.
No one is
suggesting that people fry on a beach. But many scientists believe
that "safe sun" - 15 minutes or so a few times a week
without sunscreen - is not only possible but helpful to health.
One is Dr.
Edward Giovannucci, a Harvard University professor of medicine
and nutrition who laid out his case in a keynote lecture at
a recent American Association for Cancer Research meeting in
suggests that vitamin D might help prevent 30 deaths for each
one caused by skin cancer.
would challenge anyone to find an area or nutrient or any factor
that has such consistent anti-cancer benefits as vitamin D,"
Giovannucci told the cancer scientists. "The data are really
so impressed the American Cancer Society's chief epidemiologist,
Dr. Michael Thun, that the society is reviewing its sun protection
guidelines. "There is now intriguing evidence that vitamin
D may have a role in the prevention as well as treatment of
certain cancers," Thun said.
dermatologists may be coming around. "I find the evidence
to be mounting and increasingly compelling," said Dr. Allan
Halpern, dermatology chief at Memorial Sloan-Kettering Cancer
Center in New York, who advises several cancer groups.
he said, is a lack of consensus on how much vitamin D is needed
or the best way to get it.
is ideal. Even if sunshine were to be recommended, the amount
needed would depend on the season, time of day, where a person
lives, skin color and other factors. Thun and others worry that
folks might overdo it.
tend to go overboard with even a hint of encouragement to get
more sun exposure," Thun said, adding that he'd prefer
people get more of the nutrient from food or pills.
is difficult. Vitamin D occurs naturally in salmon, tuna and
other oily fish, and is routinely added to milk. However, diet
accounts for very little of the vitamin D circulating in blood,
contain the nutrient, but most use an old form - D-2 - that
is far less potent than the more desirable D-3. Multivitamins
typically contain only small amounts of D-2 and include vitamin
A, which offsets many of D's benefits.
As a result,
pills might not raise vitamin D levels much at all.
advisers can't even agree on an RDA, or recommended daily allowance
for vitamin D. Instead, they say "adequate intake"
is 200 international units a day up to age 50, 400 IUs for ages
50 to 70, and 600 IUs for people over 70.
think adults need 1,000 IUs a day. Giovannucci's research suggests
1,500 IUs might be needed to significantly curb cancer.
D may do this is still under study, but there are lots of reasons
to think it can:
studies observing large groups of people found that those with
higher vitamin D levels also had lower rates of cancer. For
some of these studies, doctors had blood samples to measure
vitamin D, making the findings particularly strong. Even so,
these studies aren't the gold standard of medical research -
a comparison over many years of a large group of people who
were given the vitamin with a large group who didn't take it.
In the past, the best research has deflated health claims involving
other nutrients, including vitamin E and beta carotene.
animal studies show that vitamin D stifles abnormal cell growth,
helps cells die when they are supposed to, and curbs formation
of blood vessels that feed tumors.
is more common in the elderly, and the skin makes less vitamin
D as people age.
D gets trapped in fat, so obese people have lower blood levels
of D. They also have higher rates of cancer.
too, are prone to cancer, and their damaged kidneys have trouble
converting vitamin D into a form the body can use.
winter days, the sun's rays come in at too oblique an angle
to spur the skin to
make vitamin D. That is why nutrition experts think vitamin
D-3 supplements may be especially helpful during winter, and
for dark-skinned people all the time.
much of the pill variety can cause a dangerous buildup of calcium
in the body. The government says 2,000 IUs is the upper daily
limit for anyone over a year old.
On the other
hand, D from sunshine has no such limit. It's almost impossible
to overdose when getting it this way. However, it is possible
to get skin cancer. And this is where the dermatology establishment
and Dr. Michael Holick part company.
ago, Holick helped make the landmark discovery of how vitamin
D works. Until a few years ago, he was chief of endocrinology,
nutrition and diabetes and a professor of dermatology at Boston
University. Then he published a book, "The UV Advantage,"
urging people to get enough sunlight to make vitamin D.
am advocating common sense," not prolonged sunbathing or
tanning salons, Holick said.
is rarely fatal, he notes. The most deadly form, melanoma, accounts
for only 7,770 of the 570,280 cancer deaths expected to occur
in the United States this year.
1 million milder forms of skin cancer will occur, and these
are the ones tied to chronic or prolonged suntanning.
sunburns - especially in childhood and among redheads and very
fair-skinned people - have been linked to melanoma, but there
is no credible scientific evidence that moderate sun exposure
causes it, Holick contends.
problem has been that the American Academy of Dermatology has
been unchallenged for 20 years," he says. "They have
brainwashed the public at every level."
of Holick's department, Dr. Barbara Gilchrest, called his book
an embarrassment and stripped him of his dermatology professorship,
although he kept his other posts.
faulted his industry ties. Holick said the school has received
$150,000 in grants from the Indoor Tanning Association for his
research, far less than the consulting deals and grants that
other scientists routinely take from drug companies.
industry has spent money attacking him. One such statement from
the Sun Safety Alliance, funded in part by Coppertone and drug
store chains, declared that "sunning to prevent vitamin
D deficiency is like smoking to combat anxiety."
ago, the dermatology academy launched a "Don't Seek the
Sun" campaign calling any advice to get sun "irresponsible."
It quoted Dr. Vincent DeLeo, a Columbia University dermatologist,
as saying: "Under no circumstances should anyone be misled
into thinking that natural sunlight or tanning beds are better
sources of vitamin D than foods or nutritional supplements."
is hardly unanimous, though, even among dermatologists.
statement that 'no sun exposure is good' I don't think is correct
anymore," said Dr. Henry Lim, chairman of dermatology at
Henry Ford Health System in Detroit and an academy vice president.
if vitamin D may turn out to be like another vitamin, folate.
High intake of it was once thought to be important mostly for
pregnant women, to prevent birth defects. However, since food
makers began adding extra folate to flour in 1998, heart disease,
stroke, blood pressure, colon cancer and osteoporosis have all
fallen, suggesting the general public may have been folate-deficient
D, "some people believe that it is a partial deficiency
that increases the cancer risk," said Hector DeLuca, a
University of Wisconsin-Madison biochemist who did landmark
studies on the nutrient.
dozen major studies are under way to test vitamin D's ability
to ward off cancer, said Dr. Peter Greenwald, chief of cancer
prevention for the National Cancer Institute. Several others
are testing its potential to treat the disease. Two recent studies
reported encouraging signs in prostate and lung cancer.
As for sunshine,
experts recommend moderation until more evidence is in hand.
skin can handle it, just like the liver can handle alcohol,"
said Dr. James Leyden, professor
emeritus of dermatology at the University of Pennsylvania, who
has consulted for sunscreen makers.
like to have wine with dinner, but I don't think I should drink
four bottles a day."
D is produced by your skin in response to exposure to ultraviolet
radiation from natural sunlight.
about Vitamin D:
2. The healing rays of natural sunlight (that generate vitamin
D in your skin) cannot penetrate glass. So you don't generate
vitamin D when sitting in your car or home.
3. It is nearly impossible to get adequate amounts of vitamin
D from your diet. Sunlight exposure is the only reliable way to
generate vitamin D in your own body.
4. A person would have to drink ten tall glasses of vitamin D
fortified milk each day just to get minimum levels of vitamin
D into their diet.
5. The further you live from the equator, the longer exposure
you need to the sun in order to generate vitamin D. Canada, the
UK and most U.S. states are far from the equator.
6. People with dark skin pigmentation may need 20 - 30 times as
much exposure to sunlight as fair-skinned people to generate the
same amount of vitamin D. That's why prostate cancer is epidemic
among black men -- it's a simple, but widespread, sunlight deficiency.
7. Sufficient levels of vitamin D are crucial for calcium absorption
in your intestines. Without sufficient vitamin D, your body cannot
absorb calcium, rendering calcium supplements useless.
8. Chronic vitamin D deficiency cannot be reversed overnight:
it takes months of vitamin D supplementation and sunlight exposure
to rebuild the body's bones and nervous system.
9. Even weak sunscreens (SPF=8) block your body's ability to generate
vitamin D by 95%. This is how sunscreen products actually cause
disease -- by creating a critical vitamin deficiency in the body.
10. It is impossible to generate too much vitamin D in your body
from sunlight exposure: your body will self-regulate and only
generate what it needs.
11. If it hurts to press firmly on your sternum, you may be suffering
from chronic vitamin D deficiency right now.
12. Vitamin D is "activated" in your body by your kidneys
and liver before it can be used.
13. Having kidney disease or liver damage can greatly impair your
body's ability to activate circulating vitamin D.
14. The sunscreen industry doesn't want you to know that your
body actually needs sunlight exposure because that realization
would mean lower sales of sunscreen products.
15. Even though vitamin D is one of the most powerful healing
chemicals in your body, your body makes it absolutely free. No
William Grant and Dr. Mercola
discuss Vitamin D and Cancer Link Part 1