Understanding LDL Cholesterol

Often called “bad” cholesterol, LDL is a lipoprotein particle in the blood that can contribute to heart disease when levels are too high.

Low-density lipoprotein, or LDL, is the most common form of cholesterol in the bloodstream. Each particle contains a lipoprotein shell surrounding a cholesterol core.

Even though it carries the label “bad” cholesterol, LDL is not automatically harmful. The body needs it to help protect nerves and to produce cells and hormones.

High-density lipoprotein, or HDL, is the other main type of cholesterol and is often described as “good” cholesterol. The liver produces both LDL and HDL.

When LDL levels are elevated, it can collect in blood vessel walls as plaque. Over time, that buildup may lead to atherosclerosis, also known as hardening of the arteries.

Atherosclerosis can increase the likelihood of heart attack, stroke, and death. If plaque develops in arteries that supply the brain, abdomen, arms, or legs, it can also cause intestinal damage and peripheral arterial disease.

High cholesterol is shaped by both inherited and lifestyle-related factors. About 20 percent of the world’s population is believed to have elevated levels of lipoprotein(a), or Lp(a), a form of LDL cholesterol. Lp(a) is considered a risk factor for plaque formation well before the usual age when heart disease appears.

In an observational study of more than 283,000 adults in the United Kingdom, researchers found that measured Lp(a) was linked with atherosclerotic cardiovascular disease, adding to evidence of the variant’s medical importance.

Because there is no specific treatment for Lp(a), people who carry it should keep their LDL cholesterol as low as possible. Unlike general high LDL cholesterol, which can often be improved with lifestyle changes and medication, elevated Lp(a) is largely determined by genetics.

The American Heart Association does not currently advise universal screening for Lp(a), but some physicians, including George Thanassoulis, MD, of McGill University in Montreal, suggest testing because more targeted therapies for high Lp(a) may become available soon.

Although less common, another inherited condition can also cause unusually high cholesterol: familial hypercholesterolemia, or FH. This disorder affects about 1 million Americans and can raise LDL levels early in life, potentially leading to premature heart attacks if it is not treated. A blood test can confirm the diagnosis, though the condition is relatively rare.

Overall cholesterol testing is recommended by the American Heart Association. Since cholesterol usually causes no symptoms until heart disease or other complications develop, regular blood tests, also called lipid panels, are important. Ask your physician or primary care provider at your next visit.

LDL Cholesterol Facts

Nearly 94 million adults in the United States—almost 40 percent of the population—have total cholesterol levels above the normal range. Slightly more than half of adults with high cholesterol are being treated to lower it.

A desirable LDL level is below 100 mg/dL. A reading from 100 to 159 mg/dL is considered at risk, while 160 mg/dL or higher is considered dangerous.

How to Lower LDL Cholesterol

Healthy lifestyle habits are the first line of defense against high LDL cholesterol. If lifestyle changes are not enough, a doctor may also prescribe cholesterol-lowering medication.

Avoid a diet high in saturated and trans fats. Diets rich in saturated fats, which are found in animal products such as full-fat dairy and in many processed foods, can raise LDL and total cholesterol.

Trans fats, sometimes found in fast food and many commercially baked breads, cookies, cakes, chips, crackers, and snack foods, can also raise LDL cholesterol while lowering HDL cholesterol.

Instead, the American Heart Association recommends eating more fruits, vegetables, poultry, fish, nuts, and nontropical vegetable oils.

Get regular exercise. The American Heart Association recommends at least 150 minutes of moderate aerobic exercise each week, ideally spread across several days. For those just starting out, low-impact aerobic activity is a good place to begin.

Exercise affects cholesterol in two ways: it raises HDL cholesterol and increases the size of LDL particles, making them less likely to form plaque on the coronary artery walls.

Keep blood sugar levels in check. For people with diabetes or prediabetes, monitoring blood sugar is also important. High blood sugar can raise LDL cholesterol, lower HDL cholesterol, and weaken the lining of arteries.

Keep your weight in a healthy range. A body mass index, or BMI, of 30 or higher is typically linked with a greater risk of abnormal LDL and total cholesterol levels.

Watch your waistline. In addition to overall weight, abdominal fat and waist circumference can increase the risk of high cholesterol.

For men, a waist measurement of 40 inches (102 centimeters) or more raises risk. For women, the threshold is 35 inches (89 centimeters) or more.

Quit tobacco. Even though it can be difficult, stopping tobacco use can help prevent high cholesterol. If you do not smoke, do not start.

Tobacco smoke damages blood vessel walls, making it easier for plaque to accumulate. Smoking also lowers HDL cholesterol.

Cholesterol-lowering drugs. Depending on family history, genetic risk, or lifestyle, healthy habits may not always be enough to lower LDL cholesterol.

If you and your doctor find that your numbers are not improving, medication may help manage high cholesterol.