Epidemic Of Atherosclerosis. Part 2
What is the cause of this new epidemic? Before taking up our discussion of ways to
forestall a heart attack, it might therefore be well to understand more clearly the basic
physiology involved. Let us start with a closer look at the arteries, the vessels that
carry fresh blood from the heart to the billions of cells in our bodies that are in
constant need of nourishment. Upon careful examination, we find that the arteries are not
the simple tubes we have pictured them to be. Viewing them in cross section, we see that
their structure is more like that of a garden hose, containing three layers of tissue in
the walls. The inside layer or lining of the artery, which doctors call the intima9
consists of a slippery membrane somewhat similar to the mucous membrane on the inside of
your mouth. The in-between layer, known as the media, is formed of muscle fiber. This
enables the blood vessel to expand and contract with the heartbeat, to facilitate the flow
of blood through it. The outer layer, called the adventitia, is composed of coarse strong
fiber& which provide added strength to the artery. In both the outer and the intermediate
layers, there are tiny intrinsic blood vessels which nourish the artery itself. The
thickness and exact composition of the three layers vary, depending upon an artery's size
and location. Of the changes that may occur in the arteries as a result of disease, there
are two types which concern us here. Both kinds have traditionally been known by the
general term, "arteriosclerosis," which means hardening or thickening of the arteries.
Actually, however, there are two kinds of hardening of the arteries. One occurs when
calcium deposits in the middle layer of the artery cause it to become brittle and hard.
For this reason, it is sometimes called a "pipestem" artery. Such calcification does not
necessarily obstruct the blood flow, and is usually harmless from a clinical point of
view. The other type of change, on the other hand - and it is the more frequent one - has
serious consequences. It consists of a thickening of the inner wall of the artery by
deposits of fats: cholesterol (a fatty alcohol), fatty acids, and the like, together with
calcium.
As these deposits grow, the passageways or canals of the arteries become narrower, much in
the same way as the drain from your kitchen sink becomes clogged with grease deposits. The
result is that less and less blood can flow through the narrowed opening to the tissues or
organs that depend on it for life. Your "pipes" have become clogged. At the same time, the
swelling of the lining cells and roughening of the inner surface provide sites for
formation of blood clots inside the narrowed artery. If the blockage is complete in vital
arteries that feed the heart muscle, a heart attack - or as we physicians call it, a
coronary thrombosis - occurs. If this disaster occurs in the cerebral arteries of the
brain, a "stroke," sometimes called a heart attack in the head, results. When the small
arteries of the kidneys are affected, Bright's disease, formerly called "dropsy," and
other diseases ensue. But whether the thickening and blocking process takes place in the
heart, head, or kidneys, it is essentially the same disease. Doctors refer to it as
atherosclerosis. About a century ago, during an autopsy, a German pathologist named
Rudolph Virchow laid open an artery to examine its interior wall. Along the lining he
observed deposits of mushy fat that he called atheromata, a Greek work meaning "porridge."
It was from this word that we derived our term, atherosclerosis. Embedded among the cells
of the artery wall along with the fat, Virchow observed some glistening crystals. These
turned out to be cholesterol. But how did these fats get into the artery walls? This
question has puzzled scientists for the past 100 years, and it is still being pursued in
various fields of research. The first theory advanced by researchers was that of
"imbibition," which held that fat droplets were absorbed directly from the blood stream
through the lining of the artery walls. When a weakening of the "ground" substance or
actual structure of the artery wall occurred, cholesterol - the main offender - and its
related fats were deposited in the artery wall. This theory has been supported by the
recent discovery that these fatty deposits, especially cholesterol, exist in the same
proportion in the artery wall as in the bloodstream itself.
Another theory that seeks to explain the way in which the fatty deposits get into the
artery walls held that they did not come from the blood stream primarily, but were
manufactured within the cells of the vessel wall. It has also been claimed that fat
molecules are normally absorbed by the artery wall without leaving a harmful residue of
acid crystals. But some abnormal condition, such as high blood pressure, may force an
excessive amount of the fat molecules into the wall. Then the artery cannot absorb the
full amount, and deposits gradually build up. Other researchers have believed that the fat
droplets find their way into the artery wall through the tiny vessels that supply blood to
the artery itself. According to this theory, a hemorrhage or series of small hemorrhages
may occur in these tiny vessels. A clot is formed, which deposits fat particles in the
artery wall when the small vessels break down. My own conclusion, based upon years of
animal, laboratory, and human research, plus experience with innumerable patients, is
this: Atherosclerosis results from an impairment of the body's ability to utilize (or
metabolize) normally not only the fats eaten in the diet, but also those that are in the
body itself. This impairment is further aggravated by the body's inability to withstand
stress or tension; and by deficiencies in the supply of hormones from vital glands such as
the thyroid, the adrenals, and the sex glands. In addition, there are other factors that
influence the individual's susceptibility to atherosclerosis, or death from a heart attack
or stroke. These include such things as inherited or constitutional factors, and the
coagulability of the blood. It is easy to see how complex the problem really is. The
danger of oversimplification is great. However, one causative factor that stands out
continuously above and beyond all others, important as they are, is fat in the diet. And
it is this factor that we can control.
These fats from our foods enter our blood stream where, like sharks cruising about, they
seek out the weak or vulnerable spots in the arteries. Here they attack, enter, and
deposit or nest themselves. These fatty deposits then acquire calcium, and the hardening
process begins in the arteries. Each particle becomes a captain around which rally the
silent "Men of Death," who wage a relentless struggle. Soon they begin to throttle our
life flow. Our blood vessels then engage in a vain effort to halt the armada of killers we
now harbor within our arteries. Special fat-eating cells are rushed to these spots, where
the fats and cholesterol have breached the barrier or wall and entered the artery. In the
life-and-death struggle that ensues, the fat-eating cells try to engulf the cholesterol
and fat particles, and may succeed temporarily in the "counter-attack." Dr. Timothy Leary,
the distinguished Boston pathologist, in 1933 first devised ingenious methods of lighting
up, refracting, and photographing this deadly drama. It was seen that inevitably the
special fat-fighting cells are themselves engulfed by the repeated tidal waves of
cholesterol and fats washed into the blood and artery walls by fat-containing foods such
as butter, eggs, cream, milk, meat fats, and other animal fats in our diet.
Why is
the epidemic particularly strong in the U.S.A.? If you are a typical American, whether you
know it or not you consume an unbalanced, obesity-producing diet. Drs. Louis Katz and J.
Stamler, prominent researchers in this field, called it "a pernicious combination of
overnutrition and undernutrition - excessive in calories, carbohydrates, lipids and salt;
and frequently substandard in certain critically important amino acids, minerals and
vitamins."
It is not surprising that this situation exists. The science of nutrition, a comparative
newcomer to the medical field, has up until recently been concerned almost exclusively
with undernutrition. People have been urged to "eat the right foods" and to provide
plently of meat, eggs, milk, and cheese for their children. In most areas of the world,
this problem of getting enough nourishing food to eat is still of primary importance. But
it is not the problem in America. Our problem is somewhat the opposite: "living too high
on the hog." Our diet is too rich in fat as well as calories, refined sugars, starches,
and oils. At the same time, it is low in essential nutriments, minerals and other vital
requirements. The exact relationship between the amount of fat you eat and the production
of cholesterol in your body is still a very complex question. Investigators differ on some
points. Concerning one aspect of the problem, though, we are all agreed: the cholesterol
found in the blood is made largely in the liver from fats in the diet. It is also believed
that cholesterol is produced in the arterial walls themselves. But the main source and the
one that we can to a great extent control is fat in our food.
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