Which lipoprotein is referred to as 'good cholesterol' due to its ability to lower blood cholesterol levels?

High-density lipoprotein (HDL) is known as 'good cholesterol' primarily because of its role in transporting cholesterol from the arteries and tissues back to the liver, where it can be metabolized and excreted. This process helps to reduce the risk of cholesterol accumulation, which can lead to atherosclerosis—a condition characterized by the buildup of plaques in blood vessels.

High-density lipoprotein achieves this by aiding in reverse cholesterol transport, effectively lowering overall blood cholesterol levels and contributing to a healthier cardiovascular profile. Elevated levels of HDL are often associated with a reduced risk of heart disease, whereas low levels may indicate an increased risk.

In contrast, low-density lipoprotein (LDL) is often referred to as 'bad cholesterol' because it can contribute to the build-up of fatty deposits in arteries, which can obstruct blood flow. Very low-density lipoprotein (VLDL) and intermediate-density lipoprotein (IDL) also carry triglycerides and cholesterol but do not facilitate the same beneficial effects on cardiovascular health as HDL does.