Cornell And Korean Researchers Report
New Anti-Cancer Mechanism Of VitaminC
Linda McCandless
Cornell University Extension
A team of scientists from Cor
nell University, working at the
New York State Agricultural Ex
periment Station, and from Seoul
National University, South
Korea, report a new mechanism
by which vitamin C fights cancer.
Their findings appear in the Jan.
12 issue of Lancet, the interna
tional journal for physicians pub
lished in London.
C.Y. Lee, Cornell professor of
food science and technology, and
his South Korean colleagues, Ki
Won Lee, Hyong Joo Lee and
Kyung-Sun Kang, found that vi
tamin C blocks the carcinogenic
effects of hydrogen peroxide on
intercellular communication.
Until this finding, the mechanism
for vitamin C’s inhibitory effects
on carcinogenic tumor promotion
was not understood.
“Vitamin C has been consid
ered one of the most important
essential nutrients in our diet
since the discovery in 1907 that it
prevents scurvy,” says Lee. “In
addition, vitamin C has several
important functions in our body
for the synthesis of amino acids
and collagen, wound healing, me
tabolism of iron, lipids and cho
lesterol and others. In particular,
vitamin C is a well known anti
oxidant that scavenges free radi
cals.” (An anti-oxidant is one of
many chemicals that reduce or
prevent oxidation, thus prevent
ing cell and tissue damage from
free radicals in the body.)
“Vitamin C prevents the inhi
bition of gap-junction intercellu
lar communication (GJIC) in
duced by hydrogen peroxide,”
says Lee. GJIC is essential for
maintaining normal cell growth.
Inhibition of GJIC is strongly re
lated to the carcinogenic process,
especially to tumor promotion.
Hydrogen peroxide, a tumor
promoter, inhibits GJIC by
changing a special protein,
connexin43. When rat liver epi
thelial cells were treated with vi
tamin C, the researchers report,
inhibition of GJIC induced by
hydrogen peroxide was prevent
ed.
Since other free-radical scav
engers, such as propylgallate and
Trolox did not prevent inhibition
of GJIC by hydrogen peroxide,
as reported previously, Lee and
his coworkers believed that vita
min C’s antitumor activity oper
ated through a mechanism other
than by scavenging free radicals.
The report adds that quercetin,
a phytochemical found in apples,
has even stronger anticancer ac
tivity than vitamin C. (Phyto
chemicals, such as flavanoids and
polyphenols, are plant chemicals
that contain protective, disease
preventing compounds.)
“The most powerful weapon
we have in the fight against can
cer is prevention,” concludes Lee.
“A diet rich in phytochemicals
and vitamin C will reduce the
risk of cancer. These phytochem
icals and nutrients are most read
ily available in fresh fruits and
vegetables.” These recommenda
tions echo those of Lee and his
Cornell colleagues in a report in
the journal Nature (June 22,
2000).
In the Lancet article, the re
searchers suggest that “inhibiting
tumor promotion” (a reversible
and long-term process) may be a
more practical strategy in pre
venting cancer than “preventing
tumor initiation” (an irreversible
and short-term process).
Lancet, which is published
weekly from editorial offices in
London and New York, meets
the needs of physicians by adding
to their clinical knowledge and
alerting them to current issues af
fecting the practice of medicine
world-wide. The journal is avail
able online at www.lancet.com.
Americas Heart
Association.^^
Fighting Heart Disease and Stroke
It keeps
more than
memories
alive.
AMERICAN HEART
ASSOCIATION
MEMORIALS & TRIBUTES
Family Living
Focus
by
Sharon
McDonald
Blair Co. Extension
Savvy Supplement Use
One of the fastest growing in
dustries in the United States is
the dietary supplement industry.
When you walk through your
local supermarket, drugstore or
even at the mall you will see
aisles of supplements that are
marketed on the premise that
they will help improve your
health and well being.
Given the abundance of prod
ucts there is both accurate and
conflicting information available
about dietary supplements. In
order to help you and I make
wise choices the Food and
Drug’s Center for Food Safety
and Applied Nutrition developed
information to help guide con
sumers in making decisions
about whether or not to use a di
etary supplement.
For many people the use of a
dietary supplement can have
positive health benefits, but
under some conditions the use of
such products is really not neces
sary and can be harmful to the
individual. So if you are consid
ering the use of a supplement,
whether it be vitamins, minerals,
herbal products or some other
substance you need to ask your
self some questions before start
ing dietary supplement use.
Do I need to think about my
total diet? Yes. The best way to
obtain the nutrients you need is
through a varied and balanced
diet.
There are times however when
this may not be possible and a di
etary supplement is beneficial in
maintaining nutrient stores.
However, there are cases
where too much of a nutrient can
cause problems and to this end
the government has established
recommended upper safe limits
of vitamins and minerals. Just
remember that more is not neces
sarily better when it comes to
supplement intake.
Should 1 check with my doctor
or healthcare provider before
using a supplement? Definitely,
yes! This is especially so for cer
tain populations such as preg
nant or nursing women, those
with a chronic health problem
such as high blood pressure,
heart disease or diabetes, if you
are taking other medications and
for children. Many supplements
contain active ingredients that
can affect different people in dif
ferent ways, so don’t put yourself
at unnecessary risk. Some
supplements can interact with
medications, both prescription
and over the counter. For exam
ple, Coumadin, ginkgo biloba
(herb), aspirin, and vitamin E
each act to thin the blood and if
taken together can increase the
possibility of internal bleeding.
Some other tips would include
asking yourself;
• Do the claims for this prod
Lancaster Farming, Saturday, April 6, 2002-B
uct sound too good to be true? If
they do, then this is not the prod
uct for you. Many times very
simplistic conclusions are drawn
from complex information with
an exaggerated claim made in
order to sell a product. Try to
seek out accurate and reliable
sources of information before
making a decision to use the
product. Unfortunately, there are
no “quick fixes” for health prob
lems so don’t be mislead by dra
matic claims.
• Other myths that you may
hear are “even if a product
doesn’t help, it at least can’t
hurt.’’ You can not assume this
to be the case. We are just begin
ning to leam about the effects of
supplements on our bodies. So
for many of these products the
jury is still out on how much and
exactly what component of the
vitamin, mineral or herb is safe
for our health.
• “When I see the term ‘natu
ral’ that means that a product is
healthful and safe.” The term
natural on a label is not well de
fined and can be used to imply
benefits of health and safety
when it has not been scientifical
ly proven. The term natural does
not assure wholesomeness or that
these food-like substances have a
milder effect than a drug. For ex
ample, many weight loss prod
ucts claim to be “natural” or
“herbal” but this does not neces
sarily make them safe.
• “A product is safe when
there is no cautionary informa
tion on the product label” is an
other myth. Manufacturers of di
etary supplements may not
necessarily include warnings
about potential adverse effects.
Dietary supplements do not un
dergo the same rigorous testing
that drugs undergo before being
marketed, so if you want to
know about the safety of a spe
cific product you should contact
the manufacturer directly. It is
the manufacturer’s responsibility
to determine that the supplement
it produces or distributes is safe
and that there is evidence that
label claims are truthful and not
misleading.
So if you are taking a dietary
supplement or considering a
supplement whether it be vita
min, mineral, herbal or other
think about these questions and
for more information check with
your health care provider or go
to the FDA website www.cfsan.f
da.gov under dietary supple
ments.
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