What is cholesterol?
Cholesterol is a waxy substance that occurs naturally in all parts of the body and that your body needs to function normally. It is present in cell walls or membranes everywhere in the body, including the brain, nerves, muscle, skin, liver, intestines, and heart. Your body uses cholesterol to produce many hormones, vitamin D, and the bile acids that help to digest fat. It takes only a small amount of cholesterol in the blood to meet these needs.
Blood cholesterol is a combination of the cholesterol manufactured by the body and that supplied by animal foods.
What are "normal" Blood Cholesterol Levels?
The National Institutes of Health and the American Heart Association have recommended that the blood cholesterol level of adults should not exceed 200 mg/dl. They have developed the following guidelines for all adults of all ages: less than 200 mg/dl total cholesterol is "desirable blood cholesterol:, 200-239 is "borderline high blood cholesterol", and 240 mg/dl or above is "high blood cholesterol".
How Is High Blood Cholesterol Diagnosed?
High blood cholesterol is diagnosed by checking levels of cholesterol in your blood. It is best to have a blood test called a lipoprotein profile to measure your cholesterol levels.
The lipoprotein profile will give information about your:
- Total cholesterol
- Low-density lipoprotein (LDL) bad cholesterol: the main source of cholesterol buildup and blockage in the arteries
- High-density lipoprotein (HDL) good cholesterol: the good cholesterol that helps keep cholesterol from building up in arteries
- Triglycerides: another form of fat in your blood
How Often Should Blood Cholesterol Levels Be Checked?
All adults over 20 should be tested for HDL and total cholesterol at least once every five years. If your total cholesterol is borderline-high and your HDL is above 35 you should be rechecked in a year or two. If your total cholesterol is borderline-high or high and your HDL is below 35, you should have a complete lipid profile to determine LDL. Then, if your LDL is under 130, you can wait five years to be retested. But if your LDL is 130 or higher and depending on your other risk factors, you'll need to be retested yearly, modify your diet and take other steps to reduce risk.
Why is high cholesterol bad?
If you have too much cholesterol in your bloodstream, it can lead to atherosclerosis, a condition in which fat and cholesterol are deposited in the walls of the arteries in many parts of the body, including the coronary arteries feeding the heart. In time, narrowing of the coronary arteries by atherosclerosis can produce the signs and symptoms of heart disease, including angina and heart attack.
Your blood cholesterol level has a lot to do with your chances of getting heart disease. High blood cholesterol is one of the major risk factors for heart disease. The higher your blood cholesterol level, the greater your risk for developing heart disease or having a heart attack.
A high level of fats and cholesterol in the blood stream, (called hyperlipidemia), is a major factor in coronary heart disease. Scientific studies have shown that people with a blood cholesterol level of 265 mg/dl have four times the risk of developing heart disease than do those with a level of 190 mg/dl or lower. Heart disease is the #1 cause of death in the United States, killing more people than all forms of cancer combined.
What are some other names for high cholesterol?
How Does Cholesterol Cause Heart Disease?
When there is too much cholesterol (a fat-like substance) in your blood, it builds up in the walls of your arteries. Over time, this buildup causes "hardening of the arteries" so that arteries become narrowed and blood flow to the heart is slowed down or blocked. The blood carries oxygen to the heart, and if enough blood and oxygen cannot reach your heart, you may suffer chest pain. If the blood supply to a portion of the heart is completely cut off by a blockage, the result is a heart attack.
High blood cholesterol itself does not cause symptoms, so many people are unaware that their cholesterol level is too high. It is important to find out what your cholesterol numbers are because lowering cholesterol levels that are too high lessens the risk for developing heart disease and reduces the chance of a heart attack or dying of heart disease, even if you already have it. Cholesterol lowering is important for everyone--younger, middle age, and older adults; women and men; and people with or without heart disease.
Special arteries, called coronary arteries, bring blood to the heart. Narrowing of your coronary arteries due to plaque can stop or slow down the flow of blood to your heart. When the arteries narrow, the amount of oxygen-rich blood is decreased. This is called coronary heart disease (CHD). Large plaque areas can lead to chest pain called angina. Angina happens when the heart does not receive enough oxygen-rich blood. Angina is a common symptom of CHD.
Some plaques have a thin covering and can burst (rupture), releasing cholesterol and fat into the bloodstream. The release of cholesterol and fat may cause your blood to clot. A clot can block the flow of blood. This blockage can cause angina or a heart attack.
Lowering your cholesterol level decreases your chance for having a plaque burst and cause a heart attack. Lowering cholesterol may also slow down, reduce, or even stop plaque from building up.
What are lipoproteins?
Lipoproteins transport cholesterol and other fats in the blood stream. Because cholesterol is like a fat it will not mix with water. Therefore, in order for blood cholesterol and fats to be able to travel through the blood stream, the body has to combine them with protein. This combination of blood cholesterol or fats (i.e. lipids) and protein is called a lipoprotein.
The two major kinds of lipoproteins are LDLs and HDLs. LDL stands for low density lipoprotein; it contains mostly cholesterol and little protein.
LDL is commonly known as the "bad" cholesterol because scientists believe it deposits its cholesterol onto artery walls. Under 130 mg/dl is desirable, 130 to 159 is borderline-high and 160 or more is high.
HDL stands for high density lipoprotein; it contains mostly protein and little cholesterol. HDL is commonly know as the "good" cholesterol because it is believed to take cholesterol away from the body's cells and transport the cholesterol to the liver for processing or removal. HDL (good) cholesterol protects against heart disease, so for HDL, higher numbers are better. A level less than 40 mg/dL is low and is considered a major risk factor because it increases your risk for developing heart disease. HDL levels of 60 mg/dL or more help to lower your risk for heart disease.
What are Triglycerides?
Most fats are more technically referred to as triglycerides. Triglycerides are the most common form of fat stored in the body and circulating in the blood. It is the form fat takes from the food we eat. Fat in table meat is composed of triglycerides. Triglyceride levels range from about 50 to 200 mg/dl depending on age and sex. A level between 200-400 is high.
Things that can increase triglyceride levels include:
- Physical inactivity
- Cigarette smoking
- Excessive alcohol use
- Very high carbohydrate diet
- Certain diseases and drugs
- Genetic disorders
How do you get high cholesterol?
Your blood cholesterol level is affected not only by what you eat but also by how quickly your body makes LDL-cholesterol and disposes of it. In fact, your body makes all the cholesterol it needs, and it is not necessary to take in any additional cholesterol from the foods you eat.
Patients with heart disease or those who are at high risk for developing it typically have too much LDL-cholesterol in their blood. Many factors help determine whether your LDL-cholesterol level is high or low.
A variety of things can affect cholesterol levels. These are things you can do something about:
- Diet. Saturated fat and cholesterol in the food you eat make your blood cholesterol level go up. Saturated fat is the main culprit, but cholesterol in foods also matters. Reducing the amount of saturated fat and cholesterol in your diet helps lower your blood cholesterol level.
- Weight. Being overweight is a risk factor for heart disease. It also tends to increase your cholesterol. Losing weight can help lower your LDL and total cholesterol levels, as well as raise your HDL and lower your triglyceride levels.
- Physical Activity. Not being physically active is a risk factor for heart disease. Regular physical activity can help lower LDL (bad) cholesterol and raise HDL (good) cholesterol levels. It also helps you lose weight. You should try to be physically active for 30 minutes on most, if not all, days.
Things you cannot do anything about also can affect cholesterol levels. These include:
- Age and Gender. As women and men get older, their cholesterol levels rise. Before the age of menopause, women have lower total cholesterol levels than men of the same age. After the age of menopause, women's LDL levels tend to rise.
- Heredity. Your genes partly determine how much cholesterol your body makes. High blood cholesterol can run in families.
How do you treat high cholesterol?
There are two main ways to lower your cholesterol:
- Therapeutic Lifestyle Changes (TLC)--includes a cholesterol-lowering diet, physical activity, and weight management.
- Drug Treatment--if cholesterol-lowering drugs are needed, they are used together with TLC treatment to help lower your LDL.
There are several types of drugs available for cholesterol lowering including statins, bile acid sequestrants, nicotinic acid, fibric acids, and cholesterol absorption inhibitors. Your doctor can help decide which type of drug is best for you.
The five major types of cholesterol-lowering medicines are:
- Statins. Very effective in lowering LDL (bad) cholesterol levels. Safe for most people. Rare side effects to watch for are muscle and liver problems
- Bile Acid Sequestrants. Help lower LDL cholesterol levels. Sometimes prescribed with statins. Not usually prescribed as the only medicine to lower cholesterol
- Nicotinic Acid. Lowers LDL cholesterol and triglycerides, and raises HDL (good) cholesterol. Should only be used under a doctor's supervision
- Fibrates. Lower triglycerides. May increase HDL (good) cholesterol levels. When used with a statin, may increase the chance of muscle problems
- Ezetimibe. Lowers LDL cholesterol. Acts within the intestine to block cholesterol absorption