Cholesterol

What is cholesterol?

Cholesterol is a member of a family of molecules called lipids. Fat is another member of the lipid family. Like fat, cholesterol molecules can't travel through blood in their original form because they don't mix with water, the major ingredient of blood. So cholesterol and fat are packaged with protein to form lipoproteins, which can travel through the blood.

What are VLDLs, LDLs and HDLs?

VLDL, which stands for very low-density lipoprotein, is made in the liver and carries fat to other parts of your body. LDLs, which are low-density lipoproteins, carry cholesterol to different parts of the body and are considered "bad" cholesterol because they may become deposited inside blood vessel walls. HDL, which stands for high-density lipoprotein, is considered "good" because it carries the deposited pieces of cholesterol back to the liver where it is repackaged into new VLDLs or is broken down and excreted.

What do all those numbers mean?

There are usually 3 different numbers produced from a cholesterol test: a total cholesterol level, a HDL cholesterol level and a LDL cholesterol level. A total cholesterol level of less than 200 is considered desirable. Borderline results range from 200-239 with 240 or greater considered a high cholesterol level. HDL results are the opposite, the higher the number the better your HDL level. Thismeans you have more good lipoproteins to remove the deposited cholesterol from your blood vessels. A desierable number is 35 or higher. Anything less than 35 is considered low. Your LDL cholesterol number is slightly more complicated. Whether your LDL level is desirable depends on your risk for heart disease. If you are at a definite risk for heart or arterial disease than your desired level is 100 or less. For those with no heart disease and fewer than two risk factors 160 or less is desired for you. If you have no heart disease but two or more risk factors than your desired level is less than 130.

What does cholesterol have to do with heart disease?

The Framingham Heart Study established that high blood cholesterol is a risk factor for coronary heart disease (CHD). Results of the Framingham study showed that the higher the cholesterol level, the greater the CHD risk. On the other end of the spectrum, CHD is uncommon at total cholesterol levels below 150 milligrams per deciliter (mg/dL). A direct link between high blood cholesterol and CHD has been confirmed by the Lipid Research Clinics-Coronary Primary Prevention Trial (1984) which showed that lowering total and LDL ("bad") cholesterol levels significantly reduces CHD. A series of more recent trials of cholesterol lowering using statin drugs have demonstrated conclusively that lowering total cholesterol and LDL-cholesterol reduces the chance of having a heart attack, needing bypass surgery or angioplasty, and dying of CHD-related causes.

HOW TO LOWER YOUR CHOLESTEROL

Here are steps you can take to lower your blood cholesterol or keep it low:

• Follow a low saturated fat, low-cholesterol diet
• Be more physically active
• Lose weight if you are overweight
• Reduce stress in your life
• Stop smoking

BENEFITS OF LOWERING CHOLESTEROL

Recent studies have shown that cholesterol lowering in people without heart disease greatly reduces their risk for developing CHD, including heart attacks and CHD-related death. This is true for those with high cholesterol levels and for those with average cholesterol levels.

A 1995 study called the West of Scotland Coronary Prevention Study (WOSCOPS) found that cholesterol lowering reduced the number of heart attacks and deaths from cardiovascular causes in men with high blood cholesterol levels who had not had a heart attack. For 5 years, more than 6500 men with total cholesterol levels of 249 milligrams per deciliter (mg/dL) to 295 mg/dL were given either a cholesterol-lowering drug or a placebo (a dummy pill that looks exactly like the medication), along with a cholesterol lowering diet. The drug that was given is known as a statin (pravastatin), and it reduced total cholesterol levels by 20 percent and LDL ("bad") cholesterol levels by 26 percent. The study found that in those receiving the statin, the overall risk of having a nonfatal heart attack or dying from CHD was reduced by 31 percent. The need for bypass surgery or angioplasty was reduced by 37 percent and deaths from all cardiovascular causes by 32 percent. A very important finding is that deaths from causes other than cardiovascular disease were not increased, and the overall deaths from all causes were reduced by 22 percent.

In 1998, the results of the Air Force/Texas Coronary Atherosclerosis Prevention Study (AFCAPS/TexCAPS) showed that cholesterol lowering in generally healthy people with average cholesterol levels reduced their risk for a first-time major coronary event by 37 percent. Study participants had no obvious evidence of CHD and relatively usual total cholesterol levels (average of 221 mg/dL) and LDL-cholesterol levels (average of 150 mg/dL) and lower than usual HDL ("good") cholesterol levels (average of 36 mg/dL for men and 40 mg/dL for women). This study used a statin drug (lovastatin) along with a low-saturated fat, low-cholesterol diet to lower cholesterol levels. Study participants who received a placebo followed the same low-saturated fat, low-cholesterol diet. After one year, total cholesterol levels in the treatment group were lowered by 18 percent and LDL-cholesterol levels by 25 percent. The risk for a heart attack was reduced 40 percent, unstable angina 32 percent, the need for bypass surgery or angioplasty 33 percent, and cardiovascular events 25 percent. The cholesterol-lowering benefits in this study extended to both men and women as well as older adults. There were no significant differences between treatment and placebo groups in non-cardiovascular disease deaths.

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