Cholesterol is a waxy, fatlike substance that your body – mainly the
liver – produces. Cholesterol is used to make some hormones, vitamin
D, and bile acids, which help to digest fat. Cholesterol also is used
to build healthy cell membranes (walls) in the brain, nerves, muscles,
skin, liver, intestines, and heart. It only takes a small amount of
cholesterol to meet all these needs. Your body makes enough; you don't
have to get cholesterol in your diet.
Why is a high cholesterol level unhealthy?
Cholesterol causes a problem only when you have too much of it in
your blood. Excess cholesterol is deposited in the lining of the
arteries, including the arteries that feed your heart muscle. This
narrows the area inside the artery, through which blood flows. High
blood cholesterol itself does not cause symptoms, so many people are
unaware that their cholesterol level is too high.
You should have your cholesterol checked at least every five years
if your cholesterol is normal, starting at age 20. The most accurate
test is a lipoprotein profile, a blood test given after fasting for 10
to 12 hours. The test will give you these details:
- Your total cholesterol
- Your LDL ("bad")
cholesterol; this cholesterol is what's deposited in your
arteries
- Your HDL ("good") cholesterol; this
cholesterol helps keeps deposits from building up in your
arteries
- Your triglycerides; these are another form of fat in
your blood
Even without a lipoprotein profile, you can get a rough idea of your
cholesterol health if you know your total cholesterol and HDL
cholesterol. These levels can be determined through a non-fasting
cholesterol test often given at shopping malls or health fairs. If
your total cholesterol is 200 mg/dL or more, or if your HDL
cholesterol is less than 40 mg/dL for men and less than 50 mg/dL for
women, you should ask your doctor about getting a complete lipoprotein profile.
Total cholesterol
For adults, a total cholesterol level of 190 mg/dL to 224 mg/dL is
considered borderline high. Anything above 225 mg/dL is high.
HDL (high-density lipoprotein) cholesterol
An HDL level of less than 40 mg/dL for men and 50 mg/dL for women is
low; 60 mg/dL and above is considered optimal. The higher your HDL
cholesterol, the better, because it helps protect against heart disease.
LDL (low-density lipoprotein) cholesterol
The National Heart, Lung, and Blood Institute says that 100 mg/dL is
an optimal LDL level. An LDL level of 120 to 159 mg/dL is considered
borderline high; 160 mg/dL and above is high to very high. For people
with known heart disease and diabetes, the cholesterol level targets
are more stringent; ask your doctor what they are. Having a high level
of LDL cholesterol can cause fatty plaque to form along the insides of
your artery walls. This makes the arteries narrower and stiffer.
Narrower arteries mean less room for blood to flow through – like a
partially clogged pipe. This process, called atherosclerosis, develops
over a long time. It is especially dangerous if it narrows the vessels
to the heart and brain, creating a major risk for heart attack and
stroke. Build-up of cholesterol in the arteries of the legs can cause
leg and foot pain and trouble walking.