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.
SUPER-SIZE
ME: FAST
FOOD’S EFFECTS ON YOUR LIVER
Obesity is an
epidemic in America,
and in many societies around the world.
The plentiful availability of relatively inexpensive fat-
and
calorie-packed foods, along with a plethora of “effort-saving” devices,
has helped
to make us the fattest civilization in recorded human history.
In
addition to
its adverse effects upon the cardiovascular system, joints and other
important
organs, excess calories can also induce fatty changes in the liver. This condition, referred
to as hepatic steatosis,
if severe enough, can cause liver inflammation and dysfunction similar
to
chronic cirrhosis. A new study, from Sweden,
published in the journal Gut,
suggests that binging on fast food
for as little as a few weeks can, in fact, lead to measurable signs of
liver
injury.
In
this study, 12
healthy men and 6 healthy women volunteered to eat at least two fast
food meals
a day, and to adopt a sedentary lifestyle, for a period of 4 weeks. An equal number of
“control” volunteers
continued with their regular diets and levels of physical activity. On a weekly basis, all
study volunteers
underwent testing to measure the level of liver enzymes in the blood
that
become elevated in the presence of liver inflammation and injury. Additionally, the subjects
underwent weekly
scans of their livers in order to estimate the extent of fat deposition
within
their livers.
On
average, the
volunteers who agreed to be “super-sized” gained nearly 15 pounds over
the 4
week duration of this clinical study.
Blood levels of ALT, a liver enzyme that rises with injury
to the liver,
were normal in all study volunteers at the beginning of the study. At the end of the 4 week
study, however, 11
of the 18 (61%) “super-sized” volunteers had abnormally elevated levels
of ALT
in their blood, signaling the presence of inflammatory changes within
their
livers. When they
had their livers
scanned for fat content, these heavy eaters had nearly 3 times as much
fat in
their livers at the end of the study as they did when they entered the
study
only 4 weeks earlier.
Taken
together,
this study nicely shows how rapidly the binge-eating of fast food can
lead to
measurable signs of liver injury and inflammation.
The same injurious effects on the liver are
often seen in alcoholics, partly due to the great excess of calories
associated
with high levels of alcohol intake.
In
fact, the authors of this study, citing the results of their research,
suggest
that physicians consider overeating as another potential cause of liver
inflammation and injury in patients with abnormal ALT levels in the
blood, in
addition to the usual suspects of alcohol abuse, hepatitis caused by
viruses,
and liver injury caused by other substances that are known to be toxic
to the
liver. Based upon
the results of this
intriguing little clinical study, it would appear that “super-sizing”
your diet
may potentially lead to rapid and significant harm to your liver.
EXERCISE, WEIGHT &
CORONARY ARTERY DISEASE
It is well known
that obesity is linked to an increased risk of high blood pressure,
coronary
artery disease, heart attack, and congestive heart failure. There continues to be a
great deal of debate,
however, regarding the subgroup of people often referred to as the “fit
fat.” Some studies
have purported to
show that overweight people who nonetheless exercise regularly, and who
appear
to be otherwise healthy, may have approximately the same risk of heart
attack,
and death due to cardiovascular disease, as their leaner compatriots. Other studies have shown
that even vigorous
and regular exercise fails to completely erase the added health risks
associated with increasing levels of obesity.
A
new study has
evaluated the effects of physical activity and body weight, in women,
on the
risk of coronary artery disease. This
study was conducted by researchers at the Beth
Deaconess Medical
Center and
the Brigham and Women’s
Hospital in Boston,
and is featured in the current issue of the Archives
of Internal Medicine. The
data for
this research study was derived from a very large study of clinically
healthy
women. Nearly
40,000 women have been
participating in the Women’s Healthy Study, for an average of 11 years
now; and
all of them were without clinical evidence of cardiovascular disease,
cancer or
diabetes when they first entered the study.
This study was designed to assess the impact of both body weight and level of physical
activity as risk factors for
coronary artery disease (CAD).
A
total of 948
cases of new CAD were diagnosed in this huge cohort of women during the
study
(most of these 948 women experienced a heart attack, or required either
coronary artery bypass surgery or stenting of their coronary arteries). The researchers then
calculated the risk of developing
CAD for subgroups of study volunteers, based upon body mass (e.g.,
normal
weight, overweight and obese) and average level of physical activity
(physically active women who were not overweight served as the basis
for
comparison with these other subgroups).
Not
surprisingly,
the women who were both obese and physically inactive had the greatest
risk of
developing CAD (more than 2.5 times the risk of the physically active
women
with a normal body weight). The
women
who were at the next highest level of risk for CAD were those who were
obese
but physically active, and those who were overweight but physically
inactive. In fact,
the risk of CAD was
essentially identical in these two subgroups of women (nearly 2 times
the risk
of CAD, when compared to the active women with a normal body weight). The third highest risk
category for CAD was
found in women who were overweight but physically active (1.5 times the
CAD
risk as normal weight women who were active).
Next to the physically active women with a normal body
weight, the
lowest risk category for CAD was observed in the group of women with
normal
body weight who were physically inactive.
In this particular subgroup, the added risk of CAD was a
rather modest
1.08 times the risk observed in the physically active women with normal
weight.
The
results of
this study, essentially, confirm the well known increased risk of CAD
associated with either increased body mass or physical inactivity. In this study, women with both risk factors had the highest overall
incidence of CAD. This
study also
reveals that increased levels of physical activity do appear to reduce
the risk
of CAD, but not to the levels observed among women with normal body
mass. That is to
say that it appears that the increased
risk of CAD brought about by being overweight or obese cannot be
completely
eliminated by increased levels of exercise and physical activity. Previous suggestions that
being “fit and fat”
can bring the risk of CAD down to levels observed in lean individuals
appear not
to be correct, based upon this large and very high quality prospective
public
health study.
Whether
or not
the findings of this study also apply equally to men as well is unclear. However, based upon other
epidemiological
studies, it is reasonable to assume that both women and men can reduce
their
risk of CAD significantly by maintaining their body mass in the normal
range and by engaging in regular,
frequent and
vigorous exercise.
CONTAMINATION
OF SURGICAL
INSTRUMENTS IN THE OPERATING ROOM
In most cases,
operating rooms are completely set up before the patient is wheeled in. The OR technicians and
nurses bring all of
the necessary surgical instruments and supplies into the room, and open
them up
so that surgery can begin promptly once the patient is anesthetized. In some cases, delays in
getting the patient
into the operating room, or under anesthesia, may expand the amount of
time
that sterilized surgical instruments are left exposed to the open air
in the
OR. An innovative
new study from Wright
State
University,
in Dayton,
Ohio,
and just published in The Journal of Bone
& Joint Surgery, evaluated the incidence of bacterial
contamination in
trays of surgical instruments after varying durations of exposure to
the
ambient air in the operating room.
In
this study, 45
sterile trays, used to hold sterilized surgical instruments, were
opened within
a standard operating room. The
exposed
surfaces of these trays were then cultured, in standard fashion with
sterile swabs,
to identify the presence of viable bacteria on them.
Serial cultures were obtained, initially upon
opening the trays, and then at 30 minute intervals, for a total of 4
hours. The trays
were divided into three
groups, each with 15 sterile trays.
In
the first group, the sterile instrument trays were opened and left
within a
locked OR, and nobody was allowed in except for the person who
intermittently
swabbed the trays to perform cultures.
In the second group, a single person went into and out of
the OR every
10 minutes, for 4 hours. Finally,
in the
third group, all opened sterile instrument trays were initially covered
with
sterile towels, and were then subsequently uncovered, and nobody was
allowed to
enter this particular operating room except for the person performing
the
cultures.
Among
the 30
trays left uncovered throughout the experiment, 3 of them (10%) were
found to
be contaminated with bacteria immediately after they were opened! Of the remaining 27 trays
that were left
uncovered, a whopping 30% were found to have bacterial contamination
after 4
hours of being left open to the air within the operating room (even
after only
1 hour of being left open, 15% of these uncovered instrument trays had
culture-proven evidence of bacterial contamination).
There was no significant difference in the
likelihood of bacterial contamination among the uncovered trays in the
OR where
no entry was allowed versus the OR where one person was permitted to
enter and
leave the room every 10 minutes. On
the
other hand, none of the 15 instrument trays that were initially covered
immediately upon opening were found to have evidence of bacterial
contamination
4 hours after being opened.
To
summarize,
this study determined that sterile surgical instrument trays were
increasingly
likely to develop bacterial contamination over time if they were left
uncovered
after being opened. Light
human traffic
into and out of the OR did not appear to have any impact on the risk of
bacterial contamination of the uncovered instrument trays, however. On the other hand,
covering the instrument
trays until it was time to actually begin the surgical procedure
appeared to
eliminate this time-dependent risk of environmental bacterial
contamination. The
authors concluded,
therefore, that sterile surgical instrument trays should be immediately
covered
until they are ready to be used. (Seems
like a good idea to me.)
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.
