Cholesterol is a fatty substance your body needs to rebuild its cells and to make certain hormones. It's carried throughout your body in your bloodstream. Your body only requires a small amount of cholesterol.
When there's too much cholesterol in your bloodstream, you have high cholesterol. This is a very common condition. Cholesterol levels generally rise with age. Unfortunately, high cholesterol can significantly increase your risk of heart disease, stroke, and peripheral vascular disease.
Most of your body's cholesterol (about 80%) is made in your liver. The rest comes from your diet. Dietary cholesterol is found in foods from animal sources, such as eggs, meats, and dairy products. There are two important types of cholesterol you should know about:
- low-density lipoprotein (LDL), or "bad" cholesterol
- high-density lipoprotein (HDL), or "good" cholesterol
Most of the LDL, or "bad," cholesterol circulates in the blood and remains unused. Normally, the liver removes this "extra" cholesterol, but many people have more LDL cholesterol than the liver can handle. LDL cholesterol promotes buildup of harmful plaque (fatty deposits) in the walls of the arteries. The term high cholesterol refers to having high levels of LDL cholesterol.
HDL gets its "good" name by picking up LDL cholesterol from the arteries and tissues and carrying it back to the liver, where it can be broken down.
Many factors determine whether your cholesterol is high or low, including:
- age (cholesterol levels increase with age)
- alcohol consumption
- cigarette smoking
- gender (men have higher cholesterol)
- level of physical activity
- Ethnicity (South Asian and Indigenous individuals are more likely to have high cholesterol)
Another cause of high cholesterol is eating foods that are high in saturated fats and cholesterol. Other factors that can increase your cholesterol levels include an inactive lifestyle and being overweight. In some cases, high cholesterol is an inherited genetic condition, called familial hypercholesterolemia. This condition puts you at an increased chance of developing heart disease at an early age.
Some medical conditions, such as diabetes, high blood pressure, hypothyroidism, liver disease, and kidney disease can raise cholesterol levels. Certain medications can also increase your cholesterol levels.
Symptoms and Complications
LDL cholesterol in the bloodstream can settle as fatty deposits on the inside of your blood vessels. These build up over time to become plaque. Plaque can damage and clog the arteries, including the arteries feeding the heart, the brain, and the limbs. This process is called atherosclerosis (hardening of the arteries) and can result in angina (chest pain), heart attack, or stroke. High levels of LDL cholesterol cause more plaque buildup and increase the risk of a heart attack.
High cholesterol usually has no obvious symptoms. Like high blood pressure, it's a "silent" condition that offers no early warning. Most people first discover the problem during a routine blood test and physical exam. They often find they have high blood pressure as well.
You can get symptoms from the complications of high cholesterol. These include angina and pain in the calves caused by narrowed arteries to the legs. The main complications of high cholesterol are heart disease and stroke.
Making the Diagnosis
Many times, high cholesterol is diagnosed during routine blood tests to check your cholesterol level. These tests usually measure your total cholesterol level as well as your levels of LDL and HDL cholesterol. Testing is started at different ages depending on your risk factor. In Canada, people without risk factors usually start screening at the age of 40.
As part of this screening process, your doctor may give you a physical exam and ask you about your diet and medical conditions in your personal and family history. Your doctor will also check for other risk factors you may have for heart and blood vessel disease.
Treatment and Prevention
Lowering cholesterol levels with treatment reduces the risk of developing coronary artery disease, heart attack, stroke, and other disorders.
A healthy lifestyle is the best defense against high cholesterol. This also helps against other risk factors that increase your risk of heart and blood vessel disease. The following lifestyle changes are an important part of overall treatment in managing high cholesterol:
- follow a diet low in saturated fats and cholesterol
- eat a wide variety of vegetables, whole grains, fruits, nuts, and seeds
- Adopt a healthy dietary pattern (e.g. Mediterranean diet, Portfolio diet, or DASH diet)
- boost your level of physical activity (at least 150 minutes per week of moderate-to-vigorous intensity aerobic physical activity)
- maintain a healthy body weightlimit your alcohol consumption to:
- no more than 2 drinks per day (or no more than 3 drinks on special occasions) to a maximum of 10 drinks per week for women
- no more than 3 drinks per day (or no more than 4 drinks on special occasions) to a maximum of 15 drinks per week for men
If you quit smoking and keep your blood pressure down, it will help lower your risk of developing angina, heart attack, and stroke.
For people who are at a high risk for heart and blood vessel disease, drug therapy is started immediately along with lifestyle changes. For those at a moderate or low risk, lifestyle changes may be started first. Medication may be added if the cholesterol targets are not reached within a few months or if there are additional risk factors.
Medications used to treat high cholesterol include the "statins" (e.g., atorvastatin*, rosuvastatin, pravastatin, simvastatin), resins (e.g., cholestyramine, colestipol, colesevelam), fibrates (e.g., fenofibrate, gemfibrozil), cholesterol absorption inhibitors (e.g., ezetimibe), PCSK9 inhibitors (e.g., alirocumab, evolocumab) and niacin. Medications have been shown to lower the chance of further clogging of the arteries and treat cholesterol problems by lowering levels of LDL (bad) cholesterol and raising the levels of HDL (good) cholesterol. These medications must be used in addition to, not as a substitute for, healthy lifestyle changes.
Some people think that it's too late to change your habits if you've already had a heart attack or stroke, but this is not true. It's vital to reduce your cholesterol to help prevent it from happening again. Some patients with heart and blood vessel disease are now treated with a "statin" even if their cholesterol level is normal. Your body is constantly producing cholesterol, so you must take your medication and follow lifestyle changes as recommended by your doctor to prevent cholesterol levels from rising.
*All medications have both common (generic) and brand names. The brand name is what a specific manufacturer calls the product (e.g., Tylenol®). The common name is the medical name for the medication (e.g., acetaminophen). A medication may have many brand names, but only one common name. This article lists medications by their common names. For information on a given medication, check our Drug Information database. For more information on brand names, speak with your doctor or pharmacist.