What is cholesterol and how does arteriosclerosis develop?
The human body needs cholesterol to work properly. For example, cholesterol is needed to make certain and it is an important building block for cell walls. But too much cholesterol in the blood can sometimes mean an increased risk of cardiovascular disease.
Cholesterol is needed by every cell in the human body. Most of it is made in the liver. Only a small proportion comes from our diet. The bloodstream transports cholesterol from the liver to the other organs and tissues in the body. Spare cholesterol is carried back to the liver in the bloodstream.
Although cholesterol is often referred to as a “blood fat,” chemically speaking that is not quite correct. But, like fats, cholesterol does not dissolve in water (or blood), so our bodies need a special system to transport it. Cholesterol is packed into tiny parcels in the liver. The parcels are made up of cholesterol, proteins, fats (lipids) and other things in our blood. They can be transported through our bodies in the bloodstream. Because they are mainly made up of lipids and proteins, the parcels are called “lipoproteins.” There are two different kinds of lipoproteins, which differ in how densely they are packed:
- “LDL” cholesterol: “LDL” stands for “low-density lipoprotein.” This type of parcel transports cholesterol from the liver to the rest of the body. High levels of LDL cholesterol are associated with a higher risk of cardiovascular disease, which is why it is sometimes referred to as “bad” cholesterol.
- “HDL” cholesterol: “HDL” stands for “high-density lipoprotein.” This type of parcel transports cholesterol back to the liver from the body’s organs and tissues. Because high levels of HDL cholesterol are associated with a lower risk of cardiovascular disease, it is sometimes called “good” cholesterol.