What is Cholesterol?

Kendyl Garton

How do LDL and HDL differ structurally and functionally?

Although LDL and HDL are each classified as lipoproteins, they each differ both structurally and functionally.

-The structure of LDL contains a low density, but it's molecules are larger than HDL molecules. Each LDL molecule has one molecule called Apo lipoprotein. This can affect its function. "The structure of HDL is denser than LDL. It has a protein called ApoA-I, which protects it from being too modified." (Chandler, S.) Now that you know the differences between the structures of LDL and HDL, you'll now read on about the differences in their functions.


- LDL's function is to bind to cholesterol in the liver so that it can carry itself to cells throughout the body. If blood vessels become damaged during this process, LDL will "bind and accumulate along the walls of blood vessels." (Chandler, S.) This can lead to plaque formation, so high levels of LDL increases the risk for heart attack. HDL's function is to move through the blood vessels and pick up excess cholesterol. It then carries it back to the liver for breakdown. HDL helps protect against heart disease. (Chandler, S.)

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

LDL is associated with the risk for heart disease because the accumulation of cholesterol in the blood vessels leads to plaque formation. High blood pressure and plaque buildup increases your risk for heart disease. Low levels of HDL can be associated with heart disease because there's not enough to clear out the extra cholesterol in the body. (Beckerman, J.)

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

When getting your cholesterol tested three specific kinds of fats are measured: low-density lipoproteins (LDL), high-density lipoproteins (HDL), and triglycerides. They will also look at your family history.

"It's necessary to look at ALL the numbers in a cholesterol test." (Cassobhoy, A.) Here is how you interpret each value of your test:


LDL cholesterol levels: if these levels show 190 mg/dL or higher then you are at a high risk for heart disease, and treatment would include therapy and changes to your life style. If those levels or equal to or less than 189 mg/dL its recommended that you lower your LDL by 30%-50%.


HDL cholesterol levels: if these levels are less than 40 mg/dL then your risk is much higher for factors that can affect your heart and blood vessels' health.


Triglyceride levels:

- Normal: less than 150 mg/dL

- Borderline risk: 150-199 mg/dL

- High risk: 200-499 mg/dL

- Very high risk: 500 mg/dL and above

(Cassoobhoy, A.)

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

Unsaturated fats:

These fats are helpful in many ways, one including that they can improve blood cholesterol levels. They're liquids at room temperature. Foods you can find them in are plants, like nuts, seeds, and vegetable oils. In an experiment researchers tested that by replacing carbohydrates with unsaturated fats, these fats decreased levels of harmful LDL and increased HDL, therefor lowering cholesterol levels. (HARVARD T.H. CHAN)


Saturated fats:

Cutting back on saturated fats can be good for your health, as long as you replace those fats with good fats. If you eat too much saturated fat then it is bad for the heart, especially for those who have insulin issues causing them to be overweight. These fats are solids at room temperature and when too much is consumed it causes your body to work harder to break them down. It can raise LDL levels and lower HDL levels, making risk of cholesterol higher. (HARVARD T.H. CHAN)


Trans fats:

These fats are also called hydrogenated oils which are found in many fast foods and used for baked goods, frying, and processed snack foods. They contain large amounts of cholesterol and saturated fat, which is very bad for your health. Trans fats raise LDL and lower HDL even more than saturated fats do, so they are much worse for cholesterol levels. It causes your immune system to over work, therefor leading to heart disease stroke, and diabetes. It's very important to make sure these fats are limited in your diet to keep cholesterol levels low and your body healthy. (HARVARD T.H. CHAN)

Documentation of Sources

Beckerman, J. (2013, October). Heart disease and lowering cholesterol. WebMD. Retrieved from http://www.webmd.com/heart-disease/guide/heart-disease-lower-cholesterol-risk?page=5


Cassoobhoy, A. (2014, March). Understanding your cholesterol test results. WebMD. Retrieved from http://www.webmd.com/cholesterol-management/cholesterol-tests-understand-your-results?page=3



Chandler, S. (2013, August). How does LDL and HDL differ structurally and functionally. Livestrong.com. Retrieved from http://www.livestrong.com/article/401250-how-does-ldl-hdl-differ-structurally-functionally/



HARVARD T.H. CHAN (n.d.). Fats and cholesterol: out with the bad, in with the good. Retrieved from http://www.hsph.harvard.edu/nutritionsource/fats-full-story/