The Skinny on Cholesterol
Written by Dee McCaffrey, CDC
Tuesday, November 01, 2011
In the minds of most people, cholesterol means only one thing - blocked arteries and heart
attacks. Few people know the vital and integral role cholesterol plays in keeping our bodies
healthy. Cholesterol is a waxy fatty substance that is needed to give our cell membranes a
certain amount of required stiffness. Vitamin D is made from cholesterol and the action of
sunlight on the skin, and the glands of the endocrine system use cholesterol as the raw
material for making hormones, such as testosterone and estrogen. Cholesterol is also
necessary for the formation of bile in the liver. Bile contains bile salts, which are powerful
soap-like substances that break down fat globules into smaller particles so that they can
become more water-soluble. This allows fats to be used by the cells more easily and prevents
them from being stored in the liver. Cholesterol, therefore, is a good thing.
Cholesterol is only found in foods from animal sources such as eggs, meat, dairy products, fish
and shellfish. Plant foods do not contain cholesterol. Your body requires about 1,000
milligrams (1 gram) of cholesterol each day, but it does not depend upon cholesterol from foods.
On average, only about fifteen percent of the cholesterol in your body comes from dietary
sources, your body (mainly your liver) makes the other eighty five-percent. In other words, even
if you reduce your intake of dietary cholesterol to zero, your liver will make a little more
cholesterol to make sure have enough. It's that necessary for life.Conversely, if you eat more
cholesterol than normal, your liver will make less of it, so that you don't exceed the 1,000
milligram requirement. Of those 1,000 milligrams, about 800 of them are turned into bile salts. The other 200 milligrams are used for the other body functions mentioned previously.
Since cholesterol is fatty and blood is watery, the two don't mix; they are like oil and water. In
order to travel in the bloodstream, cholesterol needs to be transported by carrier molecules that
are produced by the liver called
lipoproteins
. Lipoproteins are like little bubbles that the cholesterol is enveloped in as it is being transported
through the blood to the places in the body where it is needed. Since the body uses cholesterol
in different ways, the liver makes different types of lipoproteins. These are categorized as
low density lipoproteins
(LDL),
very low density lipoproteins
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The Skinny on Cholesterol
Written by Dee McCaffrey, CDC
Tuesday, November 01, 2011
(VLDL), and
high density lipoproteins
(HDLs). All of the cholesterol that is being carried is identical; it is the lipoproteins that are
different.
VLDL and LDL are responsible for transporting cholesterol from the liver to be used by the
body's cells. HDL is responsible for "scouring" the walls of the blood vessels and collecting any
unused cholesterol and carrying it back to the liver. The liver then recycles the cholesterol or
uses it to make bile salts. This is an amazing mechanism in the body. Under normal healthy
circumstances, cholesterol levels are tightly regulated, and all cholesterol is good cholesterol!
When Cholesterol Turns Bad
As mentioned earlier, your body is programmed to make a certain amount of cholesterol each
day. It sends out this cholesterol in VLDLs and LDLs, assuming that all of it will be used. For
instance, your body assumes that you need a certain amount of cholesterol for making your
daily requirement of vitamin D and other hormones. But if you never go out into the sun, or if
when you do go out into the sun you lather up with sunblock, the cholesterol doesn't get used. Not only do you become deficient in vitamin D and hormones, but you also now have a bunch of
unused VLDL and LDL cholesterol floating around in your blood. This "free" cholesterol has two
fates: It can be protected by antioxidants until HDL can come and "rescue" it and return it to the
liver undamaged. Once it reaches the liver, it can be pumped via the bile into the large
intestine, where dietary fiber can latch on to the cholesterol and eliminate it from the body
through the bowel movement. This is why HDL is called "the good cholesterol". This would be
the ideal fate.
The other fate is more grim, and unfortunately the one that occurs in most people. The "free"
cholesterol gets attacked by free radicals and become oxidized because there aren't enough
antioxidants present in the body to protect it. The damaged cholesterol makes its way into
plaques on the inner lining of the arteries, clogging them and leading to heart disease. Since
this type of damaged cholesterol is transported in VLDLs and LDLs, it is called "the bad
cholesterol"Typically in this scenario, there isn't enough HDL scavenging around in the blood to
rescue all of the damaged cholesterol.
High cholesterol occurs when you're not eliminating enough of your unused cholesterol. Even
in fate number one, if your rescued cholesterol makes it all the way to your intestine, but there
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The Skinny on Cholesterol
Written by Dee McCaffrey, CDC
Tuesday, November 01, 2011
isn't enough fiber in your diet, most of that cholesterol will be recycled back to your liver and will
be sent back out into the bloodstream in addition to all the new cholesterol that is being made.
Also, if your liver is not generating enough HDL, then your cholesterol begins to build up by way
of fate number two.
Consumption of refined cooking oils such as soybean oil and corn oil, as well as too much sugar
and refined carbohydrates, can also raise cholesterol levels. The liver makes cholesterol from
protein, sugar, and starch, so you can end up with high cholesterol levels just by eating too
many of these types of foods, even if they don't contain cholesterol.
Restoring Healthy Cholesterol Levels The main source of high cholesterol is interference with cholesterol utilization. The best way to
manage cholesterol levels is to get enough sunshine on your skin. Twenty minutes of
unprotected exposure to the sun is enough, after that you can cover up. Secondly, you need to
eat an abundance of plant foods (fruits, vegetables, legumes, and whole grains). This way you
will have an abundance of antioxidants in your bloodstream to protect cholesterol from being
oxidized, and fiber in your intestines to remove cholesterol from your body. You can also help
your liver generate more HDLs by getting 20 to 30 minutes a day of aerobic exercise, such as
brisk walking; consuming enough omega-3's from fish and supplements; eating
monounsaturated fat from avocadoes; and cutting out trans-fats.
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