Tell your
friends about Vitamin Lady and watch the Product Credits in roll in!
Stress and Obesity, rosch stress obesity, cortisol obesity, cortisol stress overweight, adrenals overweight, vitamin lady reports stress obesity
STRESS,
AND WHY ALL OBESITY IS NOT CREATED EQUAL
By Paul J. Rosch, MD
stress124@earthlink.net
Paul Rosch, MD, FACP, is clinical professor
of medicine and psychiatry at New York Medical College and is
President of the American Institute of Stress, and Honorary
Vice-President of the International Stress Management
Association.
**
Obesity is an established risk factor for
hypertension, stroke, heart attacks, heart failure and a host of
other things ranging from lung and kidney disease to diabetes,
insulin resistance and certain cancers. It's easy to comprehend
how a lot of excess weight can elevate blood pressure and put a
strain on the heart, lungs and kidneys or that increased caloric
intake can boost blood sugar to trigger repeated releases of
insulin that eventually exhaust the pancreas and cause diabetes.
But it's not that simple. All obesity is not created equal and
where that extra fat is deposited may be more important than how
much of it there is.
It is well established that
people with apple-shaped figures, due to increased abdominal
fat, are at greatest risk for these problems. Recent research
has shed some light on the reasons for this as well as the
causes of deep belly fat. Eating too much and not exercising
enough are certainly contributing factors but may not be as
important as stress. Cortisol, a steroid hormone manufactured in
the adrenal cortex appears to be the major culprit.
Cortisol secretion is
increased in Cushing's syndrome, a disorder that is associated
with increased abdominal fat. Most cases of Cushing's syndrome
are due to a tumor that produces excess amounts of ACTH, a
pituitary hormone that stimulates the adrenal cortex to secrete
cortisol. Following removal of the tumor, this excess abdominal
fat diminishes or disappears as cortisol levels return to
normal. This led to the hypothesis that some forms of obesity
might represent a mild form of Cushing's syndrome but since most
obese people do not have elevated cortisol levels that theory
was discarded.
However, about 25 years ago,
researchers compared cortisol concentrations in samples of
subcutaneous and deep abdominal fat obtained from patients
undergoing surgery, most of whom were of normal weight. The
belly fat had higher levels of cortisol and it was subsequently
found that this was due to greater activity of an enzyme that
regenerates cortisol from inactive precursors. This finding
resurrected interest in the role of cortisol but there was
little progress until a few years ago, when advances in genetic
engineering made it possible to link the gene for this enzyme in
mice to a promoter that only activated it in fat tissue.
Genetically altered mice bred in this fashion had 2.5 times more
enzyme activity and 14 to 30% higher concentrations of cortisol
in their belly fat than normal mice. Although, as in most obese
humans, blood cortisol was not increased, these pot-bellied mice
subsequently began to exhibit insulin resistant diabetes,
hypertension and other manifestations of the metabolic syndrome
that increases risk for coronary heart disease in humans. The
clinical relevance of this is supported by a recent report that
obese men have higher levels of this cortisol recycling enzyme
activity in their fat tissue than leaner controls.
Stress causes increased
pituitary secretion of ACTH that also results in an elevation of
cortisol and a shift in fat distribution to the abdomen.
Chronically stressed primates with high cortisol levels develop
a corresponding increase in abdominal fat deposits. A study of
Swedish men similarly found that with those with the highest
levels of chronic stress also had the highest cortisol
measurements and the greatest amount of deep belly fat. Since
the only way to accurately determine the amount of hidden
abdominal fat is with expensive CT or MRI scans, most
researchers usually rely on the waist/hip ratio (WHR) that only
requires a tape measure. In one report, premenopausal women with
a high WHR reported more chronic stress and had greater
reactivity to stressful challenges compared to low WHR controls.
In another study, a high WHR in middle aged men was associated
with increased depression, anxiety, sleep disturbances and other
stress related symptoms. There are gender differences since men
are more apt to gain weight in the belly whereas women tend to
accumulate peripheral fat and such pear-shaped individuals are
less likely to suffer the metabolic complications of obesity.
Indeed, Danish researchers reported last month that older women
with excessive fat in the arms, legs, hips and buttocks had
significantly less atherosclerosis than those whose fat was
primarily abdominal. The reason appears to be that peripheral
fat secretes hormone-like substances that decrease insulin
resistance, some of which might be useful in preventing or
treating metabolic syndrome. Obesity due to stress and cortisol
is not apt to occur in younger individuals because of the
protective effects of other steroids like testosterone, estrogen
and progesterone. It is after age 40, when these sex hormones
begin to decline that we start to see what is often referred to
as" middle aged spread". Although men whose waist size is
greater than 40 inches and women whose waists are wider than 35
inches are at particular risk, significant increases in
abdominal fat can be found in those whose measurements are a few
inches less.
Abdominal fat contains more
cortisol receptors than other tissue and it has been suggested
that circulating cortisol is preferentially attracted here so
the liver can have easy access to fuel that may be needed for
physical activity during stressful situations. Deep belly fat
releases large amounts of free fatty acids into the portal
circulation that continually stimulate the liver to produce
glucose. In that regard, it should be noted that stress causes
increased secretion of adrenaline and other hormones from the
adrenal medulla that also increase fatty acid and blood sugar
levels. When stimulated in vitro, abdominal fat cells
secrete many more inflammatory molecules than fat cells from
subcutaneous sites. Abdominal fat cells produce large amounts of
IL-6 and other inflammatory cytokines that can contribute to
diabetes, insulin resistance and coronary disease. This is
important since there is a striking correlation between
increased abdominal fat and increased levels of C-reactive
protein (CRP), a marker of inflammation that has been found to
be superior to LDL for predicting coronary events.
The $64 dollar question is
"What controls the release of fatty acids and cytokines from
visceral fat depots in the first place"? It is believed that the
signal comes from the brain since this release is cyclic rather
than constant. The brain tends to control many activities by
emitting pulsed signals at regular frequencies and chemicals are
released from deep belly fat in nine-minute cycles much like
other activities that are controlled by the cerebral cortex. How
this signal reaches its target is not clear since no humoral or
central nervous system effects can be detected. However, there
is increasing evidence to support the concept of an electrical
circulatory system in the body that mediates the myriad and
instantaneous biochemical and physiologic changes that occur in
"fight or flight" responses to stress. Björn Nordenström has
proposed that these communication pathways are analogous to
ancient Chinese concepts of meridians that conduct Qi
energy, with its antagonistic yin and yang
components being similar to positive and negative charges.
Although much more research is required, it is quite evident
that not all obesity is created equal and that cortisol and
stress can play a decisive role in determining these
differences.
SUGGESTED READING
Björntorp P. Visceral obesity: a
"civilization" syndrome. Obes Res 1993;1:206-222.
Rosch PJ, Clark CC. De-Stress, Weigh
Less. 2001; St, Martin's Press, New York.
Björntorp P. Centralization of body fat pp
213-224 in Björntorp P, ed. International Textbook of
Obesity. 2001; John Wiley & Sons, Chichester.
Ridker PM, Rifai N, Rose L, et al.
Comparison of C-reactive protein and low-density lipoprotein
cholesterol levels in the prediction of first cardiovascular
events. N Engl J Med 2002; 347:1557-65.
Visser M, Bouter LM, McQuillan GM, Wener MH,
Harris TB. Elevated C-reactive protein levels in overweight
and obese adults. JAMA 1999;282:2131-2135.
Reaven GR. Importance of identifying the
overweight patient who will benefit the most by losing weight.
Ann Intern Med 2003;138:420-423.
Keywords: rosch stress obesity, cortisol obesity, cortisol
stress overweight, adrenals overweight, the vitamin lady
reports stress obesity
*Product is shipping with 24 business hours on all in stock product. Back
ordered items generally ship with 5 to 7 business days. If your order will
not be shipped for longer than 10 business days, we will notify you by email.
**See our
Shipping Policy for
heavy items.
Prices subject to change without notice.
