High Blood Cholesterol
By Mayo Clinic Staff
Cholesterol is found in every cell in your body. Cholesterol is used by your body to build healthy cells, as well as some vital hormones.
When you have high cholesterol, you may develop fatty deposits in your blood vessels. Eventually, these deposits make it difficult for enough blood to flow through your arteries. Your heart may not get as much oxygen-rich blood as it needs, which increases the risk of a heart attack. Decreased blood flow to your brain can cause a stroke.
High cholesterol (hypercholesterolemia) is largely preventable and treatable. A healthy diet, regular exercise and sometimes medication can go a long way toward reducing high cholesterol.
High cholesterol has no symptoms. A blood test is the only way to detect high cholesterol.
When to see a doctor
Ask your doctor for a baseline cholesterol test at age 20 and then have your cholesterol retested at least every five years. If your test results aren't within desirable ranges, your doctor may recommend more frequent measurements. Your doctor may also suggest you have more frequent tests if you have a family history of high cholesterol or other risk factors, like smoking or diabetes.
Cholesterol is carried through your blood, attached to proteins. This combination of proteins and cholesterol is called a lipoprotein. You may have heard of three different types of cholesterol, based on what type of cholesterol the lipoprotein carries. They are:
- Low-density lipoprotein (LDL). LDL, or "bad," cholesterol transports cholesterol particles throughout your body. LDL cholesterol builds up in the walls of your arteries, making them hard and narrow.
- Very-low-density lipoprotein (VLDL). This type of lipoprotein contains the most triglycerides, a type of fat, attached to the proteins in your blood. Like LDL cholesterol, VLDL cholesterol makes LDL cholesterol particles larger, causing your blood vessels to narrow. If you're taking cholesterol-lowering medication but have a high VLDL level, you may need additional medication to lower it because VLDL is high in triglycerides.
- High-density lipoprotein (HDL). HDL, or "good," cholesterol picks up excess cholesterol and takes it back to your liver.
Various factors within your control - such as inactivity, obesity and an unhealthy diet - contribute to high LDL cholesterol and low HDL cholesterol. Factors beyond your control may play a role, too. For example, your genetic makeup may keep cells from removing LDL cholesterol from your blood efficiently or cause your liver to produce too much cholesterol.
You're more likely to have high cholesterol that can lead to heart disease if you have any of these risk factors:
- Smoking. Cigarette smoking damages the walls of your blood vessels, making them likely to accumulate fatty deposits. Smoking may also lower your level of HDL, or "good," cholesterol.
- Obesity. Having a body mass index (BMI) of 30 or greater puts you at risk of high cholesterol.
- Poor diet. Foods that are high in cholesterol, such as red meat and full-fat dairy products, will increase your total cholesterol. Eating saturated fat, found in animal products, and trans fats, found in some commercially baked cookies and crackers, also can raise your numbers.
- Lack of exercise. Exercise helps boost your body's HDL "good" cholesterol while lowering your LDL "bad"cholesterol. Not getting enough exercise puts you at risk of high cholesterol.
- High blood pressure. Increased pressure on your artery walls damages your arteries, which can speed the accumulation of fatty deposits.
- Diabetes. High blood sugar contributes to higher LDL cholesterol and lower HDL cholesterol. High blood sugar also damages the lining of your arteries.
- Family history of heart disease. If a parent or sibling developed heart disease before age 55, high cholesterol levels place you at a greater than average risk of developing heart disease.
- High cholesterol can cause atherosclerosis, a dangerous accumulation of cholesterol and other deposits on the walls of your arteries. These deposits - called plaques - can reduce blood flow through your arteries. If the arteries that supply your heart with blood (coronary arteries) are affected, you may have chest pain (angina) and other symptoms of coronary artery disease.
- If plaques tear or rupture, a blood clot may form at the plaque-rupture site - blocking the flow of blood or breaking free and plugging an artery downstream. If blood flow to part of your heart stops, you'll have a heart attack. If blood flow to part of your brain stops, a stroke occurs.
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