Blood cholesterol has a big effect on the risk of having a heart attack or stroke, but not all cholesterol is bad. Too much of one type of cholesterol and too little of another can affect heart disease risk. According to the American Heart Association, or AHA, each year more than 1 million people have heart attacks in the U.S. It is therefore important to understand the difference between the good and bad cholesterol and know their levels.
Identification
Cholesterol is a waxy material that does not dissolve in blood. So, in order to be transported to different parts of the body where it is needed for various life functions, it is carried by lipoproteins, says the National Institutes of Health. Low-density lipoprotein, or LDL, is known as "bad" cholesterol. High-density lipoprotein, or HDL, is known as "good" cholesterol. These two types of lipids are measured in a blood cholesterol test called a "lipoprotein profile," says the NIH.
Effects
LDL cholesterol is known as bad cholesterol because it builds up in arteries and blood vessels that go to the heart and brain and causes their narrowing and eventual blockage, says the NIH. According to the AHA, HDL cholesterol is good cholesterol because it helps to prevent cholesterol from building up in the arteries and also removes cholesterol from the artery walls and carries it back to the liver where it is eliminated from the body.
Levels
For HDL cholesterol, which protects against heart disease, higher levels are best. HDL levels of 60 mg/dL or more are considered desirable and a level below 40 mg/dL is considered low and increases the risk for heart disease, says the NIH. For LDL cholesterol, low levels are best. According to the NIH, an LDL level below 100 mg/dL is desirable, 160 to 189 mg/dL is considered high and 190 mg/dL or higher is considered very high.
Risk Factors
Some factors that can cause increased LDL levels include genetic factors and a diet that has saturated fats, trans fats and dietary cholesterol, reports the NIH. According to MayoClinic.com, lifestyle factors have the greatest effect on HDL levels. Factors that lower HDL levels and increase heart disease risk include smoking, being overweight, a diet containing saturated and trans fats, physical inactivity and excessive drinking.
Considerations
To achieve healthy levels of HDL and LDL, the AHA advises a diet that has healthier fats, is low in sodium and is high in fruits, vegetables, whole grains, fat-free and low-fat dairy products and high-fiber foods. Also, eating fish such as salmon, trout or haddock at least two times a week, nuts and other foods high in omega-3 fatty acids are beneficial for improving LDL and HDL levels. Quitting smoking, managing weight and performing regular aerobic physical activity can increase HDL, according to MayoClinic.com.
