Why Cholesterol Matters

Cholesterol is a waxy, fat-like substance found in the walls of cells in all parts of the body, from the nervous system to the liver to the heart. The body uses cholesterol to make hormones, bile acids, vitamin D, and other substances.

The body makes all the cholesterol it needs. Cholesterol circulates in the bloodstream but cannot travel by itself. As with oil and water, cholesterol (which is fatty) and blood (which is watery) do not mix. So cholesterol travels in packages called lipoproteins, which have fat (lipid) inside and protein outside.

Two main kinds of lipoproteins carry cholesterol in the blood:

■ Low density lipoprotein, or LDL, which also is called the “bad”cholesterol because it carries cholesterol to tissues, including the arteries. Most of the cholesterol in the blood is the LDL form. The higher the level of LDL cholesterol in the blood, the greater your risk for heart disease.

■ High density lipoprotein, or HDL, which also is called the “good” cholesterol because it takes cholesterol from tissues to the liver, which removes it from the body. A low level of HDL cholesterol increases your risk for heart disease.

If there is too much cholesterol in the blood, some of the excess can become trapped in artery walls. Over time, this builds up and is called plaque. The plaque can narrow vessels and make them less flexible, a condition called atherosclerosis or “hardening of the arteries.”

This process can happen to blood vessels anywhere in the body, including those of the heart, which are called the coronary arteries. If the coronary arteries become partly blocked by plaque, then the blood may not be able to bring enough oxygen and nutrients to the heart muscle. This can cause chest pain, or angina. Some cholesterol-rich plaques are unstable—they have a thin covering and can burst, releasing cholesterol and fat into the bloodstream. The release can cause a blood clot to form over the plaque, blocking blood flow through the artery—and causing a heart attack.

When atherosclerosis affects the coronary arteries, the condition is called coronary heart disease or coronary artery disease. It is the main type of heart disease and this booklet will refer to it simply as heart disease.

Because high blood cholesterol affects the coronary arteries, it is a major risk factor for heart disease. Risk factors are causes and conditions that increase your chance of developing a disease.

Other major heart disease risk factors are given here:

Heart Disease Risk Factors

Risk factors are conditions or behaviors that increase your chance of developing a disease. For heart disease, there are two types of risk factors—those you can’t change and those you can. Fortunately, most of the heart disease risk factors can be changed.

Risk factors you can’t change

● Age—45 or older for men; 55 or older for women

● Family history of early heart disease—father or brother diagnosed before age 55, or mother or sister diagnosed before age 65

Risk factors you can change

● Smoking

● High blood pressure

● High blood cholesterol

● Overweight/obesity

● Physical inactivity

● Diabetes

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What Affects Cholesterol Levels?

Various factors can cause unhealthy cholesterol levels. Some of the factors cannot be changed but most can be modified. The factors are:

Those you cannot change—

■Heredity: The amount of LDL cholesterol your body makes and how fast it is removed from your body is determined partly by genes. High blood cholesterol can run in families. However, very few people are stuck with high cholesterol just by heredity —and everyone can take action to lower their cholesterol.

Furthermore, even if high cholesterol does not run in your family, you can still develop it. High cholesterol is a common condition among Americans, even young persons, and even those with no family history of it.

■ Age and sex: Blood cholesterol begins to rise around age 20 and continues to go up until about age 60 or 65. Before age 50, men’s total cholesterol levels tend to be higher than those of women of the same age—after age 50, the opposite happens. That’s because with menopause, women’s LDL levels often rise.

Those under your control—

■ Diet. Three nutrients in your diet make LDL levels rise: • Saturated fat, a type of fat found mostly in foods that come from animals;

• Trans fat, found mostly in foods made with hydrogenated oils and fats such as stick margarine, crackers, and french fries; and

• Cholesterol, which comes only from animal products. These nutrients will be discussed more later But it’s important to know that saturated fat raises your LDL cholesterol level more than anything else in your diet. Diets with too much saturated fat, trans fat, and cholesterol are the main cause for high levels of blood cholesterol—a leading contributor to the high rate of heart attacks among Americans.

■ Overweight. Excess weight tends to increase your LDL level. Also, it typically raises triglycerides, a fatty substance in the blood and in food, and lowers HDL. Losing the extra pounds may help lower your LDL and triglycerides, while raising your HDL.

■ Physical inactivity. Being physically inactive contributes to overweight and can raise LDL and lower HDL. Regular physical activity can raise HDL and lower triglycerides, and can help you lose weight and, in that way, help lower your LDL.

Knowing Your Cholesterol Level

You can have high cholesterol and not realize it. Most of the 65 million Americans with high cholesterol have no symptoms. So it’s important to have your blood cholesterol levels checked. All adults age 20 and older should have their cholesterol levels checked at least once every 5 years. If you have elevated cholesterol, you’ll need to have it tested more often. Talk with your doctor to find out how often is best for you.

Cholesterol Classifications

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Total Cholesterol

Less than 200 mg/dL Desirable

200–239 mg/dL Borderline high

240 mg/dL and above High

LDL Cholesterol

Less than 100 mg/dL Optimal (ideal)

100–129 mg/dL Near optimal/above optimal

130–159 mg/dL Borderline high

160–189 mg/dL High

190 mg/dL and above Very high

HDL Cholesterol

Less than 40 mg/dL Major heart disease risk factor 60 mg/dL and above gives some protection against heart disease women. It can slow, stop, or even reverse the buildup of plaque. It also can lower the cholesterol content in unstable plaques, making them more stable and less likely to burst and cause a heart attack.

Lowering LDL is especially important for those who already have heart disease or have had a heart attack—it will reduce the risk of another heart attack and can actually prolong life. The level to which your LDL must be lowered depends on the risk for developing heart disease or having a heart attack that you are found to have at the start of treatment.