Good vs. Bad Cholesterol
Cholesterol
can't dissolve in the blood. It must be transported through your
bloodstream by carriers called lipoproteins, which got their name
because they’re made of fat (lipid) and proteins.
The two types of lipoproteins that carry cholesterol to and from cells
are low-density lipoprotein, or LDL, and high-density lipoprotein, or
HDL. LDL cholesterol and HDL cholesterol, along with one fifth of your
triglyceride level, make up your total cholesterol count, which can be
determined through a blood test.
View an animation of cholesterol.
LDL (Bad) Cholesterol
LDL cholesterol is considered the “bad” cholesterol because it
contributes to plaque, a thick, hard deposit that can clog 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. Another condition called peripheral artery disease can develop when plaque buildup narrows an artery supplying blood to the legs.
HDL (Good) Cholesterol
HDL cholesterol is considered “good” cholesterol because it helps
remove LDL cholesterol from the arteries. Experts believe HDL acts as a
scavenger, carrying LDL cholesterol away from the arteries and back to
the liver, where it is broken down and passed from the body. One-fourth
to one-third of blood cholesterol is carried by HDL. A healthy level of
HDL cholesterol may also protect against heart attack and stroke, while
low levels of HDL cholesterol have been shown to increase the risk of
heart disease.
Triglycerides
Triglycerides are another type of fat, and they’re used to store
excess energy from your diet. High levels of triglycerides in the blood
are associated with atherosclerosis. Elevated triglycerides can be
caused by overweight and obesity, physical inactivity, cigarette
smoking, excess alcohol consumption and a diet very high in
carbohydrates (more than 60 percent of total calories). Underlying
diseases or genetic disorders are sometimes the cause of high
triglycerides. People with high triglycerides often have a high total
cholesterol level, including a high LDL cholesterol (bad) level and a
low HDL cholesterol (good) level. Many people with heart disease 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.