The key difference between HDL and LDL cholesterol is that HDL cholesterol is good cholesterol since they carry LDL cholesterol back from arteries to the liver and reduce the risk of LDL while LDL cholesterol is bad cholesterol that contributes to fatty buildups in arteries and causes heart attacks.
Cholesterol is an organic compound found in animals. It is a lipid composed of fatty acids and glycerol. Cholesterol plays a vital role in maintaining good health by creating cell membranes, hormones like estrogen and testosterone, and functioning as an intracellular messenger. Hence, it is an essential molecule at normal levels. However, abnormal levels of cholesterol can affect your health. Endogenous production of cholesterol mostly happens in the liver with the rest comes from the diet. Lipoproteins carry out the transportation of cholesterol to and from cells. High-density lipoproteins (HDL) and Low-density lipoproteins (LDL) are two types of lipoproteins. We also call HDL and LDL “good” and “bad” cholesterol respectively based on their effects on our health. This article will discuss the difference between HDL and LDL in detail.
CONTENTS
1. Overview and Key Difference
2. What is HDL Cholesterol
3. What is LDL Cholesterol
4. Similarities Between HDL and LDL Cholesterol
5. Side by Side Comparison – HDL vs LDL Cholesterol in Tabular Form
6. Summary
What is HDL Cholesterol?
High-density lipoproteins (HDL) are a type of cholesterol that has a positive effect on the cardiovascular system by acting as scavengers. It is done through the extraction of LDL cholesterol particles from the arterial walls and transporting them to the liver to be excreted as bile, thus preventing the formation of atherosclerotic plaques.
Figure 01: HDL
High level of HDL is good for health since we can associate it with long life and reduction in morbidity. On the other hand, a low level of HDL is not good since it is related to a higher incidence of heart attacks and strokes. Elevation of HDL levels can be achieved by positive lifestyle modifications and medications such as nicotinic acid, gemfibrozil, estrogen and statins.
What is LDL Cholesterol?
Low-density lipoproteins (LDL) are a type of cholesterol that is bad for our health. They carry newly formed cholesterol from the liver to various tissues in our body. More importantly, LDLs cause earlier atheroma formation progressing into atherosclerosis with narrowing of arteries and leading up to cardiovascular disease (heart attacks & strokes) at an early age and death.
Figure 02: LDL
In fact, there is a correlation between the levels of LDL and levels of HDL. It is because HDL carries LDL from the arteries to the liver and removes them from the body. Therefore, when the HDL level falls, LDL levels rise, posing the above-mentioned threats. You can reduce the LDL levels in your body through positive lifestyle modifications and compliant use of the medication statin and to a lesser level with fibrates, nicotinic acid, gemfibrozil and resins like cholestyramine.
What are the Similarities Between HDL and LDL Cholesterol?
- HDL and LDL cholesterol are two types of cholesterol present in our body.
- Also, both are lipoproteins that help in the transport of lipids from one organ to the other.
- Moreover, they have a similar, basic makeup at the molecular level with hydrophilic heads jutting out and hydrophobic/lipophilic tails jutting into the cholesterol particles.
- Besides, when they are at normal levels, they are good for our health.
- A blood test can measure both types.
What is the Difference Between HDL and LDL Cholesterol?
HDL is good cholesterol that has a positive effect on our cardiovascular system. On the other hand, LDL is a type of bad cholesterol that forms plaque in our arteries due to deposition. Therefore, this is the key difference between HDL and LDL cholesterol. Functionally, HDL levels are expected to be in the high range, while LDL levels to be in the low range, in order to maintain good health. Hence, this is another important difference between HDL and LDL cholesterol. The functional difference between HDL and LDL cholesterol is that the HDL transports cholesterol from tissues to the liver to be excreted, while LDL transports them from the liver to the tissues to be deposited.
Moreover, cardiovascular diseases resulting in heart attacks and strokes are associated with high LDL and low HDL levels. In reducing LDL levels, statin drugs have a significant role to play, whereas in elevating the HDL level it is minute. We can consider this also as a difference between HDL and LDL cholesterol. Also, nicotinic acids, fibrates, gemfibrozil have the majority action in elevating HDL, whereas the reduction in LDL levels by it is negligible. Furthermore, the resin cholestyramine acts to reduce the LDL level, but it has no effect on the HDL level.
The below infographic summarizes the difference between HDL and LDL cholesterol.
Summary – HDL vs LDL Cholesterol
In summarizing the difference between HDL and LDL cholesterol, cholesterol is an essential fat for the good health of the human body as it puts together the building blocks of cells and system function. Our body makes cholesterol, and we also consume food that contains cholesterol. There are two types of cholesterols as good cholesterol (HDL) and bad cholesterol (LDL). HDL transports bad cholesterol from other parts of our body back to the liver and removes them from the body. It reduces the risk of heart attacks and strokes. However, a high level of LDL causes atherosclerosis ending up with morbidity and mortality.
Besides, a high level of cholesterol in our body is mainly due to an unhealthy living style that includes unhealthy eating patterns, smoking, lack of physical activities, etc. So in order to lower your cholesterol levels, you must engage in regular physical activities and weight management while following a heart-healthy eating plan.
Reference:
1. “Cholesterol.” MedlinePlus, U.S. National Library of Medicine, 5 Feb. 2019, Available here.
2. “Cholesterol.” Wikipedia, Wikimedia Foundation, 17 Feb. 2019, Available here.
Image Courtesy:
1. “Atheroma” By Manu5 – (CC BY-SA 4.0) via Commons Wikimedia
2. “Hdl1” By Rfch – Own work (Public Domain) via Commons Wikimedia