The
information in this column is intended for informational
purposes only, and does not constitute medical advice or
recommendations by the author. Please consult with your
physician before making any lifestyle or medication changes, or if you
have any other concerns regarding your health.
OBESITY, LIFESTYLE & HEART
DISEASE
There
has been
much written about the link between obesity and heart disease, and the
consensus has generally been that increasing levels of excess weight
are
associated with increasing levels of coronary artery disease and heart
attacks
(myocardial infarction). More
recent
research studies have attempted to quantify the extent of added risk
associated
with specific degrees of obesity, and some have also evaluated the
benefits, if
any, of varying levels of physical fitness among obese patients (please
see my
Archives for a review of some of these recent research studies). In general, most of these
recent studies
continue to show that increasing levels of obesity are associated with
increasingly greater risks of coronary artery disease (as well as an
increasing
incidence of high blood pressure, diabetes, stroke, arthritis, some
forms of
cancer, and premature death). While
obese people can somewhat reduce health risks with regular and vigorous
exercise (the so-called “fit fat” person), most clinical research
studies have
observed that overall health risks still remain greater than those
observed in
lean people. A new
study, published in
the journal Circulation, evaluates
multiple lifestyle factors and their effects on health in obese people.
This
study was
conducted by researchers from Aarhus
University
and the Danish Cancer Society, in Denmark,
and by researchers from Harvard
University
in Boston. Nearly 55,000 men and
women participated in
the Danish Diet, Cancer and Health Study, and were free of heart
disease and
cancer upon enrolling in this study.
Participants were 50 to 64 years of age upon entry into
this study, and
were followed for an average of almost 8 years.
During the course of this study, 1,127 cases of
coronary-artery-related
complications occurred, including chest pain (angina) and myocardial
infarction. Using
body mass index (BMI),
a standardized measure of obesity that is based upon weight and height
measurements, this study revealed that each additional unit of increase
in BMI
above the normal range was associated with a 5% increase in coronary
artery
complications in women, and a 7% increase in men.
As previous studies have shown, obese
individuals who regularly engaged in 1 to 3.5 hours of exercise per
week had a
lower risk of coronary artery disease than obese patients who did not
exercise. Additionally
(and not
surprisingly), obese smokers had a considerably greater risk of
experiencing
cardiac events than obese nonsmokers.
Adhering
to a heart-healthy diet also appeared to offer some protection against
coronary
artery disease among obese patients, although the difference in the
incidence
of coronary artery disease between the “healthiest diet” and
intermediate
degrees of less healthy diets was essentially nil.
Taken
together,
the results from this very large Danish public health study confirm
other
recent studies that have shown that, even among obese people, lifestyle
factors
can have a significant influence on cardiac health.
However, none of these positive lifestyle
changes, such as exercise, a heart-healthy diet, or abstinence from
tobacco,
can completely erase the harmful effects of obesity.
There is no substitute for shedding excess
weight if you want to maintain your coronary arteries in the best
possible
shape. However, if
you are already actively
working on eliminating excess weight, you can still incrementally
decrease your
risk of heart disease by adopting a healthy lifestyle while you work
towards
achieving a healthier BMI.
EFFECTS
OF LIFESTYLE
& NUTRITION ON PROSTATE CANCER
There
have been
numerous studies on the effects of various nutritional supplements on
prostate
cancer cells growing in a Petri dish in the laboratory, and in human
prostate
cancer cells implanted into mice.
However, there is precious little data on the effects of
nutritional and
other lifestyle interventions, if any, on actual prostate cancer tumors
growing
in living human beings. As
I have often
mentioned before, there have been hundreds of previous research studies
that
have observed positive responses to experimental treatments in
laboratory cell
cultures and in mice and rats, but have subsequently failed to show any
beneficial impact when applied to human subjects.
However, a new and exciting study, just
published in the Proceedings of the
National Academy of Sciences, provides a rare glimpse into
the effects, at
the genetic level, of nutritional and lifestyle interventions on
prostate
cancer tumor cells taken from the prostate glands of men with this
disease.
This
very
intriguing study was performed by physicians and scientists at the University of California
at San Francisco and
the Preventive Medicine
Research Institute in Sausalito,
California, with
assistance from the famed J. Craig
Venter Institute in Rockville, Maryland. Initial biopsies were
taken from prostate
cancer tumors in 30 men who had previously declined surgery or other
conventional treatments for their prostate cancers, and all of these
men
subsequently participated in an intensive nutrition and lifestyle
modification
program. In all
cases, significant
improvements in obesity, elevated blood pressure, and cholesterol
levels were
observed in these 30 men after 3 months of vigorous exercise, dieting
and other
healthy lifestyle modifications. After
this 3 month period of intensive lifestyle and nutrition modification,
repeat
needle biopsies were performed on their prostate cancer tumors. Both the initial and
subsequent prostate
cancer biopsy samples were then subjected to specialized genetic
testing that
compared changes in the activity of individual genes within the tumor
cells
following 3 months of lifestyle and nutrition modification.
Gene
expression
profiling revealed that the activity of 48 individual genes had
significantly
increased following completion of the 3-month lifestyle modification
program,
while 453 genes had become less active.
The researchers then looked at all of the 501 genes that
had undergone
changes in their levels of expression, and assessed their functions as
they
related to cancer cell growth and progression.
After analyzing the functions of these 501 genes, the
researchers
determined that many of them were directly involved in critical
pathways used
by cancer cells to grow and divide.
Although
this was
only a small pilot study, it is one of only a handful of “in vivo”
clinical
research studies that have objectively studied the impact, at the level
of gene
activity, of healthy lifestyle modifications on active cancers growing
within
living human beings. As
such, the implications
of this study’s findings are potentially enormous.
Although it is not possible to tell if these
30 men will experience a reduction in the growth or spread of their
cancers as
a result of these lifestyle modifications, the objective improvement in
the
“genetic profile” of their prostate cancers, following 3 months of
intensive
diet and exercise modification, is an exciting finding in and of itself. The implications of this
study’s results
offer hope that rigorous lifestyle modifications may help to both
prevent some
cancers and to reduce the biological aggressiveness of cancers that
have
already developed. However,
this is only
a small “proof of concept” research trial.
A larger randomized clinical research trial will now have
to be
performed using a similar approach, but with a “control group” of
patients who
do not undergo any lifestyle or nutrition modifications. Additionally, this future
randomized study
will have to follow all of the participating patients for a
sufficiently long period
of time to allow any clinically significant differences between patient
groups
to become evident. Meanwhile,
this
fascinating little study offers a tantalizing look (at the genetic
level) at
the potential impact of diet and lifestyle changes on the biology of
cancer
cells growing within the human body.
GINKGO
BILOBA, ULCERATIVE
COLITIS & COLORECTAL CANCER
For
the most part,
the anti-inflammatory and anti-cancer effects of herbal supplements and
vitamins with known antioxidant activity have turned out to be quite
disappointing in human research trials, despite favorable results from
previous
laboratory research using cell cultures and laboratory mice and rats.
The
ginkgo biloba
tree is an ancient plant with no known living relatives, and is often
described
as a “living fossil.” Some
living ginkgo
trees in China are estimated to be nearly 3,000 years old, and
fossilized
specimens of this unique tree are numerous.
For thousands of years, the unique bi-lobed leaves of the
ginkgo tree
have been used for medicinal purposes, initially in traditional Chinese
medicine, and more recently, throughout the remaining world. Ginkgo leaves are known to
possess antioxidant
activity, converting cell-damaging “free radical” oxygen molecules,
which are
potentially toxic byproducts of normal metabolism, into less toxic
substances. A new
study published in the
journal Carcinogenesis has
evaluated
the effects of ginkgo biloba extract in preventing and treating
inflammatory
colitis in mice. This
study, from
laboratories at the University
of South Carolina
and McGill
University,
in Canada,
sought to demonstrate
whether or not ginkgo biloba might be useful in preventing or treating
ulcerative colitis, a chronic inflammatory disease of the rectum and
colon
associated with an increased risk of cancer development in humans.
In
this study,
inflammatory colitis was induced in laboratory mice.
The group of mice that was fed a standardized
extract of ginkgo biloba had much lower levels of inflammatory
substances in
their circulation than the mice that were not given the ginkgo
supplement. Moreover,
much lower numbers of immune cells
associated with immune-mediated inflammation, known as CD4+
T-lymphocytes, were
present in the mice that had received ginkgo supplements. The activation of
macrophages, which also
participate in the inflammatory response, was also significantly
reduced in the
mice that received ginkgo biloba.
In
this study, the use of ginkgo biloba extract was found to significantly
decrease the degree of inflammatory colitis in this mouse model of
ulcerative
colitis.
At
this time,
there are no active clinical trials assessing the effects of ginkgo
biloba in
human patients with ulcerative colitis, or other inflammatory bowel
diseases,
such as Crohn’s disease. Based
upon the
intriguing results of this laboratory study, a human clinical trial to
assess
ginkgo biloba in patients with inflammatory bowel disorders should be
initiated
now.
Disclaimer:
As always, my advice to readers is to seek the advice of your physician
before making any significant changes in
medications, diet, or level of physical activity.
