What is Cholesterol

By, Benjamin Trigg

What Are LDL and HDL?

The two types of lipoproteins that carry cholesterol to and from cells are low-density lipoprotein, or LDL, and high-density lipoprotein, or HDL. LDL cholesterol and HDL cholesterol, along with one fifth of your triglyceride level, make up your total cholesterol count, which can be determined through a blood test.

How do LDL and HDL differ structurally and functionally?

Functionally - LDL takes the cholesterol to the cells, while HDL removes excess cholesterol from the bloodstream and takes it back to the liver
Structurally - a general structure includes a core, which contains cholesterol esters and a surface monolayer of phospholipid, unesterified cholesterol and specific proteins; the difference is LDL has high density due to high protein/lipid ratio (50% cholesterol, 25% protein), and HDL is the highest in cholesterol esters and is made of 20% cholesterol and 50% protein

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

Both are must be assessed overall heart health, and for the doctor to know whether or not more cholesterol is being carried to or from cells. also too much LDL in the bloodstream can result in cholesterol plaques forming inside arteries. This results in atherosclerosis, or hardening of the arteries, and can lead to heart attack and stroke. Low levels of LDL cholesterol are associated with good cardiovascular health and a low risk of heart disease. Doctors measure HDL to ensure that levels are high enough to promote good cardiovascular health.

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

High levels of LDL cholesterol lead to atherosclerosis increasing the risk of heart attack and ischemic stroke. HDL cholesterol reduces the risk of cardiovascular disease as it carries cholesterol away from the blood stream.

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

Lipoprotein analysis (lipoprotein profile or lipid profile) measures blood levels of total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides.

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

A high level of LDL cholesterol means there's a higher risk of heart disease and stroke. LDL Cholesterol Levels: Less than 70 mg/dL = Optional goal if you're at very high risk of a heart attack or death from heart attack. High blood cholesterol signals a higher risk of heart attack and stroke.

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

Several things can be done to change the levels of both LDL and HDL in your blood. A healthy diet with reduced fat and cholesterol will increase HDL levels and decrease LDL levels. Saturated fat intake should be limited 7% or less of total calories, cholesterol should be 200mg per day or less, and Omega 3 fatty acids will increase HDL levels. It has been found that physical activity can raise HDL levels 5%. The activity needs to be consistent with at least 30 minutes a day for 5 days a week. An estimated every six pounds that are lost can increase HDL by one and lower LDL by one. Medication can also be used with the other things above.

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

Unsaturated - help reduce LDL, and lower risk of heart disease and stroke; provide nutrients to help develop and maintain cells
 Saturated - raises the level of cholesterol in blood; high levels can increase the risk of heart disease and stroke
 Trans - partially hydrogenated, raises LDL, which can clog arteries and cause heart disease, and lower HDL


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