Learn about LDL and HDL!

What are LDL and HDL?

HDl or "good" cholesterol which removes LDL or "bad" cholesterol from the bloodstream and arterial walls. It then takes the "bad" cholesterol to the liver for breakdown and processing.

LDL is "bad" cholesterol that deposits in arterial walls and starts the disorder known as atherosclerosis. This condition is defined by clogged arterial walls and lessened flexibility which can lead to heart attack and stroke.

How do LDL and HDL differ structurally and functionally?

HDL and LDL differ structurally in many ways. One way that they differ is that LDL is 50% cholesterol and 25% protein while HDL is 20% cholesterol and 50% protein, making it more dense. Not only that, but HDL is composed of mainly B-100 proteins and LDL is composed of mostly A-I and A-II proteins.

HDL and LDL differ functionally because of how they transport cholesterol. LDL transports cholesterol throughout all the cells in your body and bloodstream, causes arterial blockage. HDL on the other hand transports cholesterol away from the heart/organs and to the liver for processing/breakdown.

Why do doctors monitor the concentrations of LDL and HDL in patients' blood?

Doctors monitor LDL because excess levels of LDL in the bloodstream can cause heart attack, stroke, and other serious diseases/disorders. LDL can cause these serious problems because it can build up on the artery walls, causing blocked circulation to the heart and brain. Doctors also monitor HDL because it is necessary to support optimal heart health.

How are the concentrations of LDL and HDL associated with the risk for heart disease and associated disorders?

High concentrations of LDL can increase the risk for heart disease and similar disorders because of the massive arterial clogging it can cause. When arteries are clogged necessary nutrients (like oxygen) can be blocked from the heart, causing things like heart attack and heart failure. Not only that, but excess levels of LDL can cause atherosclerosis, a heart condition caused by the hardening of the arteries. Oppositely from LDL, high concentrations of HDL can promote good heart health. This is true because HDL can help remove LDL from the body.

What other molecules in a patient's blood are monitored along with LDL and HDL?

Other molecules measured in the blood include triglycerides, hemoglobin, glucose, creatinine, electrolytes, and blood urea nitrogen.

What do the results of a cholesterol test mean? How do patients interpret each value?

Cholesterol levels can fit into one of three categories. Desirable, borderline high, and high. Cholesterol levels in the desirable category measure less than 200, borderline high 200-239, and high 240 and up. As each level increases a patient's risk for heart attack and other disorders does the same.

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What can patients do to change the levels of LDL and HDL in their blood?

Taking on a healthy diet with lowered saturated fats can increase levels of HDL and decrease levels of LDL. Increased levels of Omega 3 can also increase HDL. Exercise can also raise and stabilize HDL levels if done consistently. If diet and exercise are not effective enough there are various treatments and medications that can effectively lower LDL.

How does intake of unsaturated, saturated, and trans fats affect cholesterol levels and overall health?

Excess saturated, unsaturated, and trans fats can increase LDL levels and lead to obesity, diabetes, heart disease, heart attack, and stroke. This can happen because of increased weight gain and arterial blockage. In moderation, unsaturated fats can improve cholesterol levels, lower inflammation of the organs, and improve overall heart health.


American Heart Association, (2015, January). Good Vs. Bad Cholesterol. American Heart Association Inc. Retrieved From:

Arielle Kamps, (2003) How Do LDL and HDL Differ Structurally and Functionally?. Demand Media.

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Medical News Today, (2014, October). What is cholesterol? What causes high cholesterol?. MediLexicon International Limited.

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Alaina Coleman, Emma McGuire & Paige Oldham