LDL and HDL Cholesterol: What's Bad and What's
Good?
Cholesterol can’t
dissolve in the blood. It has to be transported
to and from the cells by carriers called lipoproteins.
Low-density lipoprotein, or LDL, is known as “bad”
cholesterol. High-density lipoprotein, or HDL,
is known as “good” cholesterol. These
two types of lipids, along with triglycerides
and Lp(a) cholesterol, make up your total cholesterol
count, which can be determined through a blood
test.
LDL (Bad) Cholesterol
When too much LDL (bad) cholesterol circulates
in the blood, it can slowly build up in the inner
walls of the arteries that feed the heart and
brain. Together with other substances, it
can form plaque, a thick, hard deposit that can
narrow the arteries and make them less flexible. This
condition is known as atherosclerosis.
If a clot forms and blocks a narrowed artery,
heart attack or stroke can result.
HDL (good) Cholesterol
About one-fourth to one-third of blood
cholesterol is carried by high-density lipoprotein (HDL). HDL cholesterol
is known as “good” cholesterol, because high levels of HDL seem to protect
against heart attack. Low levels of HDL (less than 40 mg/dL) also
increase the risk of heart disease. Medical experts think that HDL
tends to carry cholesterol away from the arteries and back to the liver,
where it's passed from the body. Some experts believe that HDL removes
excess cholesterol from arterial plaque, slowing its
buildup.
Triglycerides
Triglyceride is a form of fat made in
the body. Elevated triglycerides can be due
to overweight/obesity, physical inactivity, cigarette smoking, excess
alcohol consumption and a diet very high in carbohydrates (60
percent of total calories or more). People with high triglycerides
often have a high total cholesterol level, including a high LDL (bad)
level and a low HDL (good) level. Many people with heart disease and/or
diabetes also have high triglyceride levels.
Lp(a) Cholesterol
Lp(a) is a genetic variation of LDL (bad)
cholesterol. A high level of Lp(a) is a significant risk factor for the
premature development of fatty deposits in arteries. Lp(a) isn’t fully
understood, but it may interact with substances found in artery walls and
contribute to the buildup of fatty deposits.
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