"Cholesterol" is a household word, but still an elusive concept for many people. And no wonder. Biochemistry is hardly simple, even for biochemists. Here are a few cholesterol review notes.
Cholesterol is a fat-like substance found in all animal cells, human and otherwise. It is essential to life. The human body manufactures all the cholesterol it needs—thus we can live without eating any cholesterol. Cholesterol is attached to protein packages called lipoproteins, which are assembled in the liver and circulate in our bloodstream. Two of the better known types of lipoproteins are HDL (high-density lipoprotein), the "good" type that carries cholesterol out of the system; and LDL (low-density lipoprotein), the "bad" type that deposits cholesterol in arterial walls, where it can build up and narrow the arteries. High LDL cholesterol is a known risk factor for heart attack.
The chart below will refresh your memory on guidelines for total cholesterol and HDL cholesterol. In the U.S., cholesterol is measured in milligrams per deciliter (mg/dL) of blood. In Canada and many other countries, it's measured in millimoles per liter (mmol/L). The latter is known as the International System. (To convert to millimoles, divide the milligrams by 38.67. To convert from millimoles to milligrams, multiply by 38.67.)
Optimal: Less than 100 mg/dL (2.58 mmol/L)
Desirable:100-129 mg/dL (2.58 -3.34 mmol/L)
Borderline-high: 130-159 mg/dL (3.37 -4.11 mmol/L)
High: 160 mg/dL or more (4.14 mmol/L or more)