HDL Cholesterol

Apolipoproteins are types or proteins that bind to lipids and create a new substance called “lipoproteins”. This new substance is unique and interesting aside from being an important substance in the body. It’s outer shell is composed mostly of proteins which allows it to be hydrophilic, or water soluble while the inside is lipidic which is compatible with cholesterol and triglycerides.

Since cholesterol is hydrophobic, it cannot travel nor mix with the water based blood stream so it will require a transport to travel from one point in the body to another. The transport that will carry these cholesterol molecules around the body are the lipoproteins. These lipoproteins will absorb cholesterol molecules and store them within tits core as it travels around the blood stream.

There are five known kinds of lipoproteins and all of which have its own characteristics and functions. These lipoproteins are: the Chylomicrons, Very Low Density Lpoproteins (VLDL), Intermediate Density Lipoproteins (IDL), Low Density Lipoproteins (LDL) and the High Density Lipoproteins (HDL). Of the five lipoproteins, the HDL and the LDL are the most popular because of their functions in the body.

The LDL, which carries cholesterols and triglycerides from the liver to the tissues are usually referred to as the “bad cholesterol” while the HDL, which carries cholesterols from the tissues to the liver are referred to as “good cholesterols”.

Now how do these HDLs function?

HDLs, move within the blood stream. As it moves around the body, it collects unused cholesterol from tissues. It will absorb these lipidic substances and store them in its core as it travels around the body. When it starts its rounds, the HDL’s shape is usually flat, but as it picks up cholesterols along the way, this lipoprotein will grow and change in size making it spherical. It will continue to grow as it absorbs cholesterol from the tissues and other lipoproteins. Then the cholesterol that it is carrying will be brought back either to the liver for excretion or recycling or to steroidogenic organs such as the ovaries, testes and adrenals.

One hypothesis which also led to the belief that HDLs are good cholesterols is that HDLs are capable of picking up the lipidic substances from the atherosclerotic areas of the arteries and deliver them back to the liver for excretion.

Based on the process and the function of these HDL molecules, it is obvious and easy to understand why this type of lipoproteins is very important for the body. With HDLs, our body maintains its health by keeping the unused cholesterol moving and preventing them from being rancid. At the same time it has properties that allow it to protect the body from suffering serious heart related illnesses.