According to the National Heart Lung and Blood Institute (NHLBI), cholesterol is transported through the blood by two types of lipoproteins: high density lipoproteins (HDL) and low density lipoproteins (LDL).
Lipoproteins
According to the NHLBI, lipoproteins are a combination of liver-produced cholesterol and proteins. Lipoproteins provide transportation for cholesterol through the bloodstream.
Cholesterol
According to the AHA, cholesterol is a soft waxy substance found among the lipids in the bloodstream. The body uses cholesterol to form cell membranes and some hormones.
HDL
According to the Mayo Clinic, high density lipoproteins are known as the good cholesterol because they transport cholesterol away from the arteries and to the liver for excretion.
LDL
According to the AHA, low density lipoprotein is known as the bad cholesterol because too much LDL can cause a plaque build-up in the arteries and lead to heart disease.
Recommended Cholesterol Levels
The Mayo Clinic recommends total cholesterol levels (HDL plus LDL) be at 200 mg/dl or lower. In addition, the Mayo Clinic also recommends HDL levels of 60 mg/dl or higher and LDL levels of 120 mg/dl or lower.
High Cholesterol
Total cholesterol levels of 240 mg/dl or higher are considered high and can cause serious medical conditions such as heart disease.
