Blood lipids include your total cholesterol, triglycerides (another fat in the blood), HDL ("good") cholesterol, and LDL ("bad") cholesterol. Knowing only your total cholesterol is insufficient, because the risk of heart and vascular disease is related to an elevated LDL cholesterol and a low HDL cholesterol. To get these numbers you have to measure your blood fats after a 12-hour fast. That usually means not eating anything after the evening meal until after your blood is drawn the following morning. (Water and medications are permissible.) This "fast" is necessary because the triglycerides are markedly elevated for several hours after a meal, and the fasting triglyceride level is necessary to calculate the bad cholesterol. (LDL cholesterol equals the total cholesterol minus the triglycerides, divided by five.)

Anyone with coronary artery disease (heart attack, angioplasty, stent, bypass surgery, carotid artery blockage, or blockage in the arteries to the legs) has atherosclerotic disease and should have their LDL cholesterol lowered below 100 mg/dl. Anyone who has a significant family history of coronary heart disease or a low HDL cholesterol should also have their LDL cholesterol lowered below 100 mg/dl.

Medication with a "statin"-type drug usually is necessary to lower the LDL cholesterol to this degree. Some individuals can lower the level of blood cholesterol with diet, but most cannot. The reason is heredity and age. Heredity determines the number of receptors, or "locks," on the liver cells.

LDL cholesterol is the key that opens these locks and lets the cholesterol inside the cells. If cholesterol does not get inside the liver cells, the liver makes more cholesterol, even if the blood level is elevated. As we age, the number of receptors decrease and our blood cholesterol gradually increases. Therefore, in most individuals, diet alone cannot lower cholesterol to an optimal range. "Statin" drugs are necessary to block the liver from making cholesterol. On the other hand, if your elevated cholesterol is associated with an elevated triglyceride, then diet and/or drugs other than, or in addition to, "statins" are usually necessary.