Cholesterol is made by some parts of the body, including the liver, but it can also get into the body from the foods which are eaten. Cholesterol has a number of different roles in the body, including its importance in cell membranes and as a precursor for hormones. Cholesterol can also be found in the blood packaged into different complexes, such as HDL and LDL. Levels of these compounds can affect a person's risk of heart disease.
Atherosclerosis and Heart Disease
Atherosclerosis is a condition which is caused by cholesterol building up in the walls of the arteries. When cholesterol gets into the walls of the arteries, it causes the arteries to become narrow and also makes the walls stiff. This can raise blood pressure and can impair blood flow. If the coronary arteries are affected by atherosclerosis, the heart may not get enough blood; if the coronary arteries become completely blocked, a heart attack will occur.
Lipoproteins
Cholesterol is a lipid, which means that it does not mix well with water-based liquids like the blood. As a result, cholesterol is found in the blood in the form of lipoproteins, which are made by the liver. Low-density lipoproteins, also known as LDL, increase a person's risk of atherosclerosis, because they carry cholesterol to other tissues. High-density lipoprotein, which is abbreviated as HDL, works as a cholesterol scavenger. High levels of HDL can protect against atherosclerosis, the American Heart Association explains.
Testing
HDL and LDL cholesterol are often measured as part of a test known as a lipid panel, which also measures triglyceride levels, as triglycerides can also affect the risk of atherosclerosis. Lipid panels are commonly ordered as part of a physical exam, particularly for patients who have a high risk of heart disease. A lipid panel is done using a blood sample.
Levels
HDL and LDL levels are usually measured in terms of mg per dL of blood. Optimal levels of LDL are under 100. Patients who have LDL levels between 160 and 189mg per dL of blood have high LDL levels, LabTestsOnline notes. Average HDL levels, on the other hand, are between 40 and 49mg per dL for men and 50 and 59mg per dL for women. High HDL levels are anything above 60mg per dL of blood.
Improving Cholesterol
Ideal cholesterol levels are high HDL and low LDL levels. Patients looking to lower their LDL levels can limit their saturated fat intake and lose weight, the National Heart Lung and Blood Institute explains. Increased physical exercise can also decrease LDL levels and can also help increase HDL. There are also medications which can raise HDL and lower LDL levels.
