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Cholesterol
Cholesterol
is a soft, waxy substance found among the lipids (fats) in the bloodstream
and in all your body's cells. It's used to form cell membranes, some hormones
and is needed for other functions. Your body makes all the cholesterol it
needs. Until it's used, this cholesterol circulates in your blood.
Cholesterol is part of a healthy body, but too much of it in your blood can
be a problem. Eating foods that contain cholesterol (called dietary
cholesterol) as well as foods high in saturated fats and trans-fats can raise
blood cholesterol. The average American man consumes about 337 milligrams of
cholesterol a day; the average woman, 217 milligrams. Although some
of the excess dietary cholesterol is removed from the body through the liver,
the American Heart Association still recommends that the average daily
cholesterol intake should be less than 300 milligrams. Someone with heart disease, should limit their daily intake to less than 200
milligrams. People with severe high blood cholesterol levels may need an even
greater reduction. Since cholesterol is in all foods from animal sources,
care must be taken to eat no more than six ounces of lean meat, fish and
poultry per day and to use fat-free and low-fat dairy products. High-quality
proteins from vegetable sources such as beans are good substitutes for animal
sources of protein.
Many
scientists think saturated fats and trans-fats have a greater impact than
dietary cholesterol in raising blood cholesterol levels. Cholesterol
and other fats can't dissolve in the blood. They have to be transported to
and from the cells by special carriers called lipoproteins (lip"o-PRO'te-inz). There are several kinds, but the
ones to be most concerned about are low-density lipoprotein (LDL) and
high-density lipoproteins (HDL). What
is LDL cholesterol or bad cholesterol? Low-density
lipoprotein is the major cholesterol carrier in the blood. If too much LDL
cholesterol circulates in the blood, it can slowly build up in the walls of
the arteries feeding the heart and brain. Together with other substances it
can form plaque, a thick, hard deposit that can clog those arteries. This
condition is known as atherosclerosis (ath"er-o-skleh-RO'sis).
A clot (thrombus) that forms near this plaque can block the blood flow to
part of the heart muscle and cause a heart attack. If a clot blocks the blood
flow to part of the brain, a stroke results. A high level of LDL cholesterol
(130 mg/dL and above) reflects an increased risk of
heart disease. That's why LDL cholesterol is often called "bad"
cholesterol. Lower levels of LDL cholesterol reflect a lower risk of heart
disease. What
is HDL cholesterol or good cholesterol? About
one-third to one-fourth of blood cholesterol is carried by high-density
lipoprotein or HDL. Medical experts think HDL tends to carry cholesterol away
from the arteries and back to the liver, where it's passed from the body.
Some experts believe HDL removes excess cholesterol from plaques and thus
slows their growth. HDL cholesterol is known as "good" cholesterol
because a high HDL level seems to protect against heart attack. The opposite
is also true: a low HDL level (less than 40 mg/dL)
indicates a greater risk of heart disease. A low HDL cholesterol level also
may increase the risk of stroke. Eating soy (ie, tofu, which is made from soybeans) can help raise
your level of high-density lipoprotein (HDL) Dishes that include soybeans, soy milk, soy flour, and textured soy protein
are good places to start. |
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