Cholesterol is an essential component of many vital organic molecules within the body, such as cellular membranes, steroid hormones (estrogen and testosterone), and bile acids. Cholesterol is a fatty substance made in the liver and is synthesized according to the body’s needs and specific requirements.

However, abnormally high levels of blood cholesterol (hypercholesterolemia), can be caused by dietary, lifestyle, and genetic factors. High blood cholesterol can build-up cholesterol-filled plaque in the arteries. This process is linked to coronary heart disease (CHD), heart attack, and strokes. Other risk factors for high blood cholesterol include low thyroid function (hypothryroidism), physical inactivity, obesity, and smoking.

Cholesterol is transported to and from the cells by special lipoprotein carriers; low-density lipoprotein (LDL) and high-density lipoprotein (HDL).

• LDL is called the “bad” form of cholesterol, because it’s the main source of cholesterol accumulation in the blood vessels to the heart and brain. The higher the LDL blood cholesterol (greater than 160 mg/dL), the greater the risk of CHD. Patients with heart disease need to maintain an LDL cholesterol level of less than 100 mg/dL (milligrams per deciliter).

• HDL is called the “good” form of cholesterol, because it doesn’t form cholesterol-filled plaque in the arteries. Instead, HDL picks up cholesterol from the arteries and carries it back to the liver for disposal from the body. A high HDL blood cholesterol may protect against heart disease. Patients with a low HDL level (less than 35 mg/dL) have a higher risk of both heart attack and stroke.