Consumer
Guide To Fats
Cholesterol
Cholesterol is sort of a "cousin" of fat. Both
fat and cholesterol belong to a larger family of chemical
compounds called lipids.
All the cholesterol the body needs is made by the liver.
It is used to build cell membranes and brain and nerve tissues.
Cholesterol also helps the body produce steroid hormones
needed for
body regulation, including processing food, and bile acids
needed for digestion.
People don't need to consume dietary cholesterol because
the body can make enough cholesterol for its needs. But the
typical U.S. diet contains substantial amounts of cholesterol,
found in foods such as egg yolks, liver, meat, some shellfish,
and whole- milk dairy products. Only foods of animal origin
contain cholesterol.
Cholesterol is transported in the bloodstream in large molecules
of fat and protein called lipoproteins. Cholesterol carried
in low-density lipoproteins is called LDL-cholesterol; most
cholesterol is of this type. Cholesterol carried in high-density
lipoproteins is called HDL-cholesterol. (See "Fat Words.")
A person's cholesterol "number" refers to the
total amount of cholesterol in the blood. Cholesterol is measured
in milligrams per
deciliter (mg/dl) of blood. (A deciliter is a tenth of a liter.)
Doctors recommend that total blood cholesterol be kept below
200
mg/dl. The average level in adults in this country is 205
to 215 mg/dl. Studies in the United States and other countries
have consistently shown that total cholesterol levels above
200 to 220 mg/dl are linked with an increased risk of coronary
heart disease. (See "Lowering Cholesterol" in the
March 1994 FDA Consumer.)
LDL-cholesterol and HDL-cholesterol act differently in the
body. A high level of LDL-cholesterol in the blood increases
the risk of fatty deposits forming in the arteries, which
in turn increases the risk of a heart attack. Thus, LDL-cholesterol
has been dubbed "bad" cholesterol.
On the other hand, an elevated level of HDL-cholesterol
seems to have a protective effect against heart disease. For
this reason, HDL-cholesterol is often called "good"
cholesterol.
In 1992, a panel of medical experts convened by the National
Institutes of Health (NIH) recommended that individuals should
have
their level of HDL-cholesterol checked along with their total
cholesterol.
According to the National Heart, Lung, and Blood Institute
(NHLBI), a component of NIH, a healthy person who is not at
high risk for heart disease and whose total cholesterol level
is in the normal range (around 200 mg/dl) should have an HDL-cholesterol
level of more than 35 mg/dl. NHLBI also says that an LDL-cholesterol
level of less than 130 mg/dl is "desirable" to minimize
the risk of heart disease.
Some very recent studies have suggested that LDL-cholesterol
is more likely to cause fatty deposits in the arteries if
it has been through a chemical change known as oxidation.
However, these
findings are not accepted by all scientists.
The NIH panel also advised that individuals with high total
cholesterol or other risk factors for coronary heart disease
should have their triglyceride levels checked along with their
HDL-cholesterol levels.
Government Advice
Dietary guidelines endorsed by the U.S. Department of Agriculture
and the U.S. Department of Health and Human Services advise
consumers to:
Reduce total dietary fat intake to 30 percent or less of
total calories.
Reduce saturated fat intake to less than 10 percent of calories.
Reduce cholesterol intake to less than 300 milligrams daily.
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