Cholesterol 101

Corynne Turner

The Basic Functions of Cholesterol

Cholesterol is very important throughout the body, as it keeps us functioning like normal and it is a major functioning component of the body.

Cholesterol makes up nearly half of the cell membrane and it maintains the strength and integrity of it. In other words it makes the membrane firmer and durable, while securing certain, needed protein within the membrane. Another important thing it does in the cells is it helps them communicate with one another.

Sleep is beneficial for us to learn and memorize things, because while sleeping the brain produces more cholesterol. Memories and learning are directly dependent on cholesterol as the neurons get lost without it.

Cholesterol is also an important part of digestion as it helps to synthesize the bile that is used to digest the food within our bodies. Also, Vitamin D is created from cholesterol, as well as steroid hormones.

Food and Cholesterol

If you do not ingest the proper amount of food with cholesterol in it the body works harder to produce enough. The foods that contain the most cholesterol are meat and eggs, along with some seafood like shrimp, crabs, and sardines. Foods that have a lot of cholesterol a lot of the time contain other essentials needed for the human body. Eating cholesterol does not raise blood cholesterol levels, if it does then it has a positive impact.


LDL (low-density lipoprotein) is the "bad" cholesterol. It contributes to plaque ( which is a thick hard deposit) which can lead to clogged arteries and make them a lot less flexible. This type of cholesterol can lead to clots, which then can become heart attacks or strokes.

HDL (high-density lipoprotein) is the "good" cholesterol because it helps to remove the LDL from the arteries. A healthy level of HDL prevents heart attacks and strokes, while lower levels can lead to heart diseases.

Structure and Function

Th biggest structural difference between LDL and HDL is their compositions. About 50% of the weight of an LDL molecule is cholesterol and only 25%is protein.HDL, on the other hand, consist of 20%cholesterol and 50 % protein. Since protein is denser than fat, HDL is more dense than. The other major structural difference between LDL and HDL relates to the types of protein they contain. LDL contains proteins called B-100 proteins, while HDL contains mostly A-I and A-II proteins. The type of protein determines function.

LDL and HDL both transport cholesterol in the blood, but themain difference in the function of the two is they deliver cholesterol to different parts of your body. LDL (the main carrier) brings cholesterol to the cells throughout your body and can cause cholesterol to buildup within your arteries. HDL can benefit your health because they carry cholesterol away from your heart and other organs and deliver it back to your liver, where it removed from the body.

Why Do Doctors Monitor LDL and HDL in the blood?

Doctors monitor LDL because it is bad, and if there is too much in the blood it can result in a buildup in the arteries leading to strokes or heart attacks

Doctors monitor HDL because they want the levels to be high to ensure that the body has the proper amounts and is health.

What Other Molecules Are Monitored?

The other molecules are triglycerides and the total amount of cholesterol in the blood.

Cholesterol Test Results

Total Cholesterol Levels:

  • High Risk: 240 mg/dL and above
  • Borderline high risk: 200-239 mg/dL
  • Desirable: Less than 200 mg/dL
If the LDL level is 190 or above is very high and an HDL level of 60 or above is excellent and the risk of heart disease is lowered drastically.

To lower cholesterol levels diet is very important and lowering the amounts of saturated fat, trans fat, and cholesterol in the diet will help. Being overweight also increases the risk for heart and cholesterol problems/ Exercise is also another good way to lower cholesterol. A lot of other factors play into it but those are the ways to fix it yourself. There are also medications to lower the cholesterol if needed.


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Cholesterol Numbers Charts: HDL, LDL, Total Cholesterol, and Triglycerides. (n.d.). Retrieved March 7, 2015, from