Good vs. Bad Cholesterol... What is LDL cholesterol and why is it so "bad"?

LDL.... what is it and how does it affect our health? LDL is a class of lipoproteins that are active in our bodies and contain a large amount of our circulating cholesterol. In simpler terms LDL are fats that move cholesterol around our bodies through our blood.

When our levels of LDL are high in our bodies the plaque in our arteries increases and builds up. This build up is bad for our circulation and other important body functions. High levels of LDL cholesterol are a factor in increased risk for heart disease and stroke. High LDL levels are also a factor in recognizing metabolic syndrome within a patient.

There are four categories of lipoproteins in our bodies, these categories are:

• Chylomicrons – contain mostly triacyclglycerols

• VLDL – carries triglycerides to the body's tissues

• LDL - “Bad Cholesterol” - too much leads to plaque buildup in arteries.

• HDL - “Good Cholesterol” - absorbs cholesterol in the blood and delivers it to the liver

In order to test for LDL cholesterol, we must use a total cholesterol test. This test shows your total cholesterol levels as well as your HDL and LDL components. A normal total cholesterol level for a person over the age of 20 is 125 mg/dL to 200 mg/dL.

Specific Levels of Cholesterol:

• Fasting triglyceride level:

• Normal: less than 150 mg/dL

• Mild hypertriglyceridemia: 150 to 499 mg/dL

• Moderate hypertriglyceridemia: 500 to 886 mg/dL

• Very high or severe hypertriglyceridemia: greater than 886 mg/dL

• LDL-C level:

• Optimal: less than 100 mg/ dL

• Near optimal/above optimal:100 to 129 mg/dL

• Borderline high: 130 to 159 mg/dL

• High: 160 to 189 mg/dL

• Very high: greater than 190 mg/dL

• HDL level:

• Low: less than 40

• High: greater than or equal to 60

*** These numbers are provided from a scholarly source and are exact to provide studied specific numbers.

Source: Lee Y, Siddiqui WJ. Cholesterol Levels. [Updated 2023 Jul 24]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK542294/

These lipoproteins are hydrophobic, meaning they fear or do not mix well with water. Since LDL is hydrophobic, LDL’s must connect with proteins to be able to flow naturally through the blood. The main function of lipoproteins is to transport lipids in the blood. High HDL and lower LDL levels are said to be healthy for our body's natural state.

A lot of researchers used to believe that if we focus mainly on our diet, we can change or modify our HDL & LDL levels. New studies are showing that dietary cholesterol has very little to no effect on overall serum cholesterol levels. While dietary cholesterol has a hard time regulating our lipoproteins, diets high in trans fatty acids and saturated fats can substantially raise our LDL cholesterol while lowering our HDL levels. A way we can try to limit our LDL consumption is to lower our saturated and trans-fat intake, reducing our intake can support our bodies while trying to regulate our lipoprotein levels.

Cardiovascular disease is a major killer in our current day and age. Researchers are attempting to differentiate between particle size of LDL and if there are effects on the different size of LDL particles. A study by Superko & Gadesam researchers stated that LDL-C and LDL-Num are not equivalent to actual size variation. For example, If the LDL-C markers are the same in a patient there is no way to know if their LDL particles are in excess or too low which results in different cardiovascular risks between the two patients. For this reason, I do not believe LDL particle size should be used in determining cardiovascular risk or state of disease. I believe LDL particle size should not be used due to cardiovascular disease having multifactorial possibilities that determine risk. When looking at patients with abnormal LDL and HDL we need to continue to monitor other factors that may contribute to increased heart disease risk such as stress, activity levels and family history.

References:

13 Foods You Should Add to Your Diet If You Have High Cholesterol. Health. Accessed October 31, 2023. https://www.health.com/foods-to-lower-cholesterol-8347635

British Heart Foundation. Blood cholesterol. Bhf.org.uk. Published May 2, 2018. https://www.bhf.org.uk/informationsupport/heart-matters-magazine/medical/tests/blood-cholesterol

Lee Y, Siddiqui WJ. Cholesterol Levels. [Updated 2023 Jul 24]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK542294/

Superko HR, Gadesam RR. Is it LDL particle size or number that correlates with risk for cardiovascular disease?. Curr Atheroscler Rep. 2008;10(5):377-385. doi:10.1007/s11883-008-0059-2

What Is the Normal Range for HDL and LDL? www.icliniq.com. Published April 30, 2022. https://www.icliniq.com/articles/blood-health/normal-range-for-hdl-and-ldl