Cholesterol is a type of fatty substance that is essential for building cell membranes and producing certain hormones and vitamin D in the body. It is a crucial component of the lipid profile, which also includes triglycerides and other lipids. Cholesterol is carried in the blood by lipoproteins, which are particles that consist of both lipids and proteins.

There are two main types of cholesterol-carrying lipoproteins:

  1. Low-Density Lipoprotein (LDL): Often referred to as "bad" cholesterol, LDL carries cholesterol from the liver to the cells. If too much LDL cholesterol is present in the blood, it can build up in the walls of arteries, forming plaques that can narrow and block blood vessels. This increases the risk of cardiovascular diseases, including heart attacks and strokes.

  2. High-Density Lipoprotein (HDL): Known as "good" cholesterol, HDL carries cholesterol away from the cells and back to the liver, where it is either broken down or passed out of the body as a waste product. Higher levels of HDL are associated with a lower risk of heart disease.