Cholesterol is a fat-like substance produced by the liver; it is also an animal sterol found in all foods from animal products. While it is an essential cellular component, cholesterol can cause atherosclerosis (i.e., arterial plaque buildup) when too much exists in the blood stream, leading to heart disease and stroke.
In Our Own Words
Cholesterol is needed in order to live, but cholesterol imbalance puts you at risk for heart disease, stroke and other diseases. Cholesterol is a waxy type of fat that circulates in your blood, carried by particles called lipoproteins. Too much low-density lipoprotein (LDL) cholesterol, often referred to as bad cholesterol, can lead to a buildup in the arteries, causing heart disease and stroke.
Not enough high-density lipoproteins (HDL) cholesterol, or good cholesterol, can also be a problem. HDL cholesterol is the kind that removes excess cholesterol from the blood, taking it to the liver to be dealt with productively. Heredity, poor diet, being overweight, smoking and a sedentary lifestyle are common causes of imbalance, or high cholesterol.
In the absence of certain conditions (e.g., familial hypercholesterolemia), maintaining a proper balance of LDL and HDL can often be achieved by following a diet low in fats and high in fiber, maintaining a healthy weight and exercising regularly.