Cholesterol
What is cholesterol?
Cholesterol is a waxy substance your body uses to protect nerves, make cell tissues and produce certain hormones. Most of the cholesterol in your body is made by your liver. Some cholesterol also comes from foods such as eggs, meats and dairy products.
Why is a high cholesterol level unhealthy?
While some cholesterol is needed for good health, too much cholesterol in your blood can raise your risk of having a heart attack or stroke.
The extra cholesterol in your blood may be stored in your arteries (blood vessels that carry blood from your heart to the rest of your body). Buildup of cholesterol, or "plaque," in your arteries will cause them to narrow. This is called atherosclerosis. Large deposits of cholesterol can completely block an artery, so the blood can't flow through.
If the coronary artery (the blood vessel that supplies blood to the muscles in your heart) becomes blocked, a heart attack can occur. If an artery that supplies blood to your brain becomes blocked, a stroke can occur.
Types of Cholesterol
- Low-density lipoproteins (LDL) deliver cholesterol to the body.
- High-density lipoproteins (HDL) remove cholesterol from the bloodstream.
Low-density lipoprotein is the major cholesterol carrier in the blood. If too much LDL cholesterol circulates in the blood, it can slowly build up in the walls of the arteries feeding the heart and brain. Together with other substances it can form plaque, a thick, hard deposit that can clog those arteries. This condition is known as atherosclerosis. A clot (thrombus) that forms near this plaque can block the blood flow to part of the heart muscle and cause a heart attack. If a clot blocks the blood flow to part of the brain, a stroke results. A high level of LDL cholesterol (160 mg/dL and above) reflects an increased risk of heart disease. If you have heart disease, your LDL cholesterol should be less than 100 mg/dL. That's why LDL cholesterol is called "bad" cholesterol. Lower levels of LDL cholesterol reflect a lower risk of heart disease.
What is HDL cholesterol?
About one-third to one-fourth of blood cholesterol is carried by HDL. Medical experts think HDL tends to carry cholesterol away from the arteries and back to the liver, where it's passed from the body. Some experts believe HDL removes excess cholesterol from plaques and thus slows their growth. HDL cholesterol is known as "good" cholesterol because a high HDL level seems to protect against heart attack. The opposite is also true: a low HDL level (less than 40 mg/dL in men; less than 50 mg/dL in women) indicates a greater risk. A low HDL cholesterol level also may raise stroke risk.
Total cholesterol level
- Less than 200 is best.
- Between 200 to 239 is borderline high.
- 240 or more means you're at increased risk for heart disease.
- Less than 130 is best.
- Between 130 to 159 is borderline high.
- 160 or more means you're at higher risk for heart disease.
- Less than 40 means you're at higher risk for heart disease.
- 60 or higher reduces your risk of heart disease.
What can I do to improve my cholesterol level?
If you smoke, stop smoking. Lifestyle changes, such as a healthy diet and regular exercise can also help lower your risk of complications from high cholesterol.
How does physical activity affect cholesterol?
Regular physical activity increases HDL cholesterol in some people. A higher HDL cholesterol is linked with a lower risk of heart disease. Physical activity can also help control weight, diabetes and high blood pressure. Aerobic physical activity raises your heart and breathing rates. Regular moderate to intense physical activity such as brisk walking, jogging and swimming also condition your heart and lungs.
Physical inactivity is a major risk factor for heart disease. Even moderate-intensity activities, if done daily, help reduce your risk. Examples are walking for pleasure, gardening, yard work, housework, dancing and prescribed home exercise.
How does tobacco smoke affect cholesterol?
Tobacco smoke is one of the six major risk factors of heart disease that you can change or treat. Smoking lowers HDL cholesterol levels and increases the tendency for blood to clot.
How does alcohol affect cholesterol?
In some studies, moderate use of alcohol is linked with higher HDL cholesterol levels. However, because of other risks, the benefit isn't great enough to recommend drinking alcohol if you don't do so already.
If you drink, do so in moderation. People who consume moderate amounts of alcohol (an average of one to two drinks per day for men and one drink per day for women) have a lower risk of heart disease than nondrinkers. However, increased consumption of alcohol brings other health dangers, such as alcoholism, high blood pressure, obesity, stroke, cancer, suicide, etc. Given these and other risks, the American Heart Association cautions people against increasing their alcohol intake or starting to drink if they don't already do so. Consult your doctor for advice on consuming alcohol in moderation.
Informations obtained from National Institute of Health.