Cholesterol is a waxy, fat-like substance found in body cells of humans and animals. Actually these descriptions refer to the substances called lipoproteins that carry cholesterol throughout the body in the bloodstream.
Lipoproteins are a combination of varying amounts of fats and proteins.
HDLs are believed to remove excess cholesterol from the body, therefore higher levels of HDLs are also believed to be associated with lower rates of heart disease. LDLs carry cholesterol in the blood to body cells. High levels of LDLs are usually associated with an elevated blood cholesterol and an increased risk of heart disease due to cholesterol and fat being deposited in the arteries. These fatty deposits decrease the interior size of the arteries so the blood supply is reduced, thus increasing the risk of heart disease and stroke. There is no proven way to control HDL and LDL levels, but diet may play a part.