Overview
Cholesterol is a waxy substance found in the blood. The body needs cholesterol to build healthy cells. But high levels of cholesterol can raise the risk of heart disease.
With high cholesterol, fats and other substances can build up in blood vessels called arteries. This buildup is called plaque. As more plaque forms over time, the arteries can become narrowed or clogged. That makes it hard for enough blood to flow through the arteries. Sometimes a piece of plaque can break loose and form a blood clot. The clot may cause a heart attack or stroke.
High cholesterol can be inherited. That means it can pass from parents to children through genes. But high cholesterol often is the result of lifestyle choices such as not getting enough exercise, not eating a balanced diet or consuming large amounts of saturated fat. You can make changes to help prevent it. And if you have high cholesterol, you can help lower it with a healthy diet, regular exercise and sometimes medicine.
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Symptoms
High cholesterol has no symptoms. A blood test is the only way to find out if you have it.
When to see a doctor
The American Heart Association recommends that children get checked, also called screened, for high cholesterol once between ages 9 and 11. Screening may start earlier if a child has a family history of high cholesterol, heart attack or stroke. Screening also may start earlier if a child has conditions such as diabetes or obesity.
The next cholesterol screening is recommended for people between ages 17 and 21. After that, many adults get their cholesterol checked every 4 to 6 years. People who have health conditions such as high blood pressure and diabetes may need to get screened more often. So might those who take cholesterol-lowering medicine. Those who have a family history of high cholesterol or heart disease also may need more-frequent screenings.
If your test results aren't within the desirable range, your healthcare professional might recommend more-frequent testing as well.
Causes
Lifestyle factors that may be within your control are the most common cause of high cholesterol. These factors include eating a diet high in saturated and trans fats and not getting enough exercise.
Sometimes factors that aren't within your control can lead to high cholesterol. These include gene changes that pass from parents to children, some health conditions, and some medicines.
Conditions that can cause high cholesterol include:
- Familial hypercholesterolemia.
- Chronic kidney disease.
- Chronic liver disease.
- Diabetes.
- HIV/AIDS.
- Hypothyroidism.
- Lupus.
- Overweight and obesity.
- Sleep apnea.
Some types of medicines taken for other health conditions also can make cholesterol levels worse. These include treatments for:
- Acne.
- Cancer.
- High blood pressure.
- HIV/AIDS.
- Irregular heartbeats.
- Organ transplants.
Cholesterol travels through the blood, attached to proteins. This mix of proteins and cholesterol is called a lipoprotein. There are various types of cholesterol. The types are based on what the lipoprotein carries. They are:
-
Low-density lipoprotein (LDL) cholesterol. This is known as the "bad" cholesterol. LDL carries cholesterol particles throughout the body. "Bad" cholesterol builds up in the walls of arteries. This makes the arteries hard and narrow.
When a gene change causes high cholesterol, the body has trouble removing LDL cholesterol from the blood. Or the body has trouble breaking down LDL cholesterol in the liver.
- High-density lipoprotein (HDL) cholesterol. This is known as the "good" cholesterol. HDL picks up extra cholesterol and takes it back to the liver.
Most often, a blood test to check cholesterol levels also measures a type of fat in the blood that is not a type of cholesterol, called triglycerides. Having a high triglyceride level also can raise the risk of heart disease. Lifestyle factors that you may be able to control play a role in triglyceride levels.
Risk factors
Risk factors for high cholesterol levels include:
- Eating habits. Eating too much saturated fat or trans fats can lead to high cholesterol. Saturated fats are found in fatty cuts of meat and full-fat dairy products. Sometimes trans fats are found in packaged snacks or desserts.
- Obesity. This complex disease involves having too much body fat.
- Lack of exercise. Exercise helps boost the body's "good" HDL cholesterol.
- Smoking. Cigarette smoking may lower the level of HDL.
- Alcohol. Drinking lots of alcohol can raise total cholesterol. Try to limit alcohol to up to one drink a day for women and up to two drinks a day for men.
- Age. Even young children can have high cholesterol. But it's much more common in people over 40. As you age, your liver becomes less able to remove "bad" LDL cholesterol.
Complications
Development of atherosclerosis
Development of atherosclerosis
If there's too much cholesterol in the blood, the cholesterol and other substances may form deposits called plaque. Plaque can cause an artery to become narrowed or blocked. If a plaque ruptures, a blood clot can form. Plaque and blood clots can reduce blood flow through an artery.
High cholesterol can lead to other health conditions called complications. With high cholesterol, a dangerous amount of plaque can build up on the walls of arteries. This is called atherosclerosis. Over time, the plaque buildup can cause arteries to narrow and block blood flow. Less blood flow through the arteries can cause complications such as:
- Chest pain, also called angina. If the arteries that supply the heart with blood are affected, that may cause chest pain. It also may cause other symptoms of a common type of heart disease called coronary artery disease.
- Heart attack. If plaques tear or break, a blood clot can form. The clot may block the flow of blood at the site where it broke. Or it may completely break free and block an artery farther away. If blood flow to part of the heart stops, a heart attack happens. A heart attack is an emergency that needs treatment right away.
- Stroke. A stroke happens when a blood clot blocks blood flow to part of the brain. It's also an emergency that needs treatment right away.
Prevention
The same heart-healthy lifestyle changes that can lower cholesterol also can help prevent high cholesterol. You can practice the following habits:
- Eat a diet that focuses on lean protein, fruits, vegetables and whole grains. Limit sodium and added sugar.
- Also limit the amount of saturated and trans fats you eat. Instead, eat foods with healthy fats such as fatty or oily fish, nuts, and olive or canola oil.
- Lose extra weight and keep it off.
- If you smoke, ask your care team to help you quit.
- Exercise on most days of the week for at least 30 minutes.
- Drink less alcohol, if at all. Limit alcohol to no more than up to one drink a day for women and up to two drinks a day for men.
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