Cholesterol Level

For a few decades now, we have been conscious of our diet and have been advised by doctors, dietitians and health experts to reduce our fats and cholesterol intake for the purpose of moderating our cholesterol levels. But what do we really know about cholesterol and why do we need to moderate our intake of it?

Cholesterol is a fatty, waxy substance found in the body. A large percentage of the cholesterol found in our body is produced by the liver (75%) while the rest of it is absorbed through our food consumption (25%). The long running belief of people and health experts is that to maintain a healthy body and to prolong our lives, we must keep our cholesterol levels low. This is because cholesterol is believed to be the main cause of atherosclerosis which entails the inflammation and hardening of the blood vessels, allegedly due to the accumulation of cholesterol along the walls of the arteries.

But recent studies have shown that Cholesterol is actually good for the body. Cholesterol is a lipidic substance that is responsible in building cell membranes and are important to produce and regenerate cells. Research also states that cholesterol is a precursor to steroid hormones, meaning without cholesterol, the body cannot produce these hormones necessary for our survival.

Because of the emergence of these recent studies, two types of lipoproteins, which are usually mistaken to be types of cholesterol were discovered. These are the Low Density Lipoproteins (LDL) and the High Density Lipoproteins (HDL) which are the new determinants of whether a person’s Cholesterol level is still healthy or already dangerous.

LDLs and HDLs are proteins that transport lipids or cholesterol within the body. Since cholesterols are oily substances, they are hydrophobic and will not be able to circulate through the blood vessels together with the blood (made mostly of water). This is where the lipoproteins come in – they carry the cholesterol around the body through the blood vessels and have no problems doing so because lipoproteins are hydrophilic substances.

LDLs carry the proteins from the liver to the cells while HDLs carry the cholesterol from the cells back to the liver either for recycling or discharge. With the roles of these two different lipoproteins in mind, the term “bad cholesterol” and “good cholesterol” was coined.

It is believed that a high level of LDL will cause a blockage or obstruction in the blood vessels causing atherosclerosis. And from this belief, LDLs are considered as bad cholesterols. On the other hand, since HDLs transport the cholesterols from the cells back to the liver, these proteins are then considered as good cholesterols. These are the main considerations of people when maintaining their cholesterol levels: they make sure that the good cholesterol in the body is high while the bad cholesterol is kept low.

But a new study on cholesterol, lipoproteins and their connection with atherosclerosis have risen and developed new theories.

Based on these recent studies, cholesterol is not bad to the body at all. In fact, the recent research tells us that the less the cholesterol found in the body, the higher the risk of the person from suffering cancer, mental illnesses, and various other sicknesses.

Apparently, the myth that LDLs are bad cholesterols was nothing but a misconception based on the belief that atherosclerosis is the accumulation of cholesterol molecules in the arterial wall. It was found out with the new research that cholesterol actually is not the cause of the mentioned disease and atherosclerosis is not an accumulation of the lipidic substance.

The true culprit to heart related sicknesses are oxidation and glycation. These two chemical reactions act in different ways but the effects are the same.

Oxidation is a process where a molecule loses an electron or gain oxygen molecule covalently or increase in oxidation state making the molecule ionically charged and unstable. When a Low Density Lipoprotein becomes oxidated and gets in contact with the walls of the artery, it causes a reaction on the tissues causing an inflammation. This inflammation will attract macrophages, which is a type of white blood cells, that will attempt to heal and repair the damage. The macrophage will absorb the oxidized lipoprotein in order to process it, break it down and prevent it from causing any more damage. But since the white blood cell is composed primarily of water and LDL carries the hydrophobic cholesterol, the white blood cell will not be able to process the hazardous substance completely until it ruptures spreading the oxidized cholesterol around the walls . This will attract even more macrophages that cannot remedy the situation causing a cycle of attracting macrophages and spreading the oxidized cholesterol. When this happens, an atheroma will be formed. This will cause the hardening and the blockage in the artery leading to atherosclerosis.

Atheromatous plaque was once believed that it was a huge deposit of fats and cholesterol in the blood vessels but actually, these are the accumulation of white blood cells that attempted to repair the damages caused by the reaction of the tissues in the arterial walls with the oxidized LDL. Based on this sequence of events, the level of cholesterol doesn’t have a direct relationship with atherosclerosis at all.

Glycation on the other hand is another chemical reaction that causes atherosclerosis. This is caused by the chemical bonding of sugar to proteins and to DNA. The sugar that has bonded with the protein will eventually be modified into a molecular structure called Advanced Glycation Endproduct (AGE). This new substance will interfere with the functions of the proteins that it has bonded with. Furthermore, AGE could also attach itself with adjacent protein strands through covalent cross links.

These cross links reduces the flexibility and elasticity of proteins causing them to stiffen. Also, these cross links may cause inflammation on tissues and may trigger auto immune responses from the body.

If a lipoprotein got cross linked, it would result to serious repercussions on the body. When this cross link gets in contact with the arterial wall, it would cause an inflammation which will trigger the immune system. After this, the whole process that will lead to atherosclerosis will start.

Based on this new study that emerged regarding the true cause of atherosclerosis, some experts believe that keeping the cholesterol level low will not guarantee a healthier body. It is actually bad for you to keep your cholesterol level too low because it plays an important role to keep our body healthy. What we can do though is maintain a level of healthy LDL’s plus a high level of HDL to clean up any free cholesterol that could cause the build up of plaque in the arteries.

To be safe, have your cholesterol level checked once in a while to see if you are still healthy. When checking your cholesterol level, your HDL and LDL counts are determined. Since lipoproteins are the carriers of cholesterol and triglycerides, which are both hydrophobic substances, knowing their numbers and ratio would determine if you are at risk. The safe HDL and LDL levels are:

• Total: 4 to 5.5 millimoles / liter
• LDL : should be less than 3.5 millimoles / liter
• HDL: should be more than 1.0 millimoles / liter
• Triglycerides: should be less than 2.0 millimoles / liter
• LDL to HDL ratio: should be less than 4

Although it is not cholesterol that is the actual cause of plaque build up, avoiding the oxidation of LDL molecules will prevent the occurence of the series of events that will lead to atherosclerosis. This is the reason why we want our LDL levels to be lower. Also, a good way to prevent any illness would be to intake as much anti oxidants as possible to prevent oxidation of cells and molecules in the body.

Good Cholesterol

Doctors, Dietitians, and Health Experts all advice that we should keep our Good Cholesterol up and that we maintain the quality of our good cholesterol. But what really is good cholesterol and why do we need it?

This good cholesterol that most advertisements and drug companies speak of is not actually a type of cholesterol but rather a lipoprotein. There is only one type of cholesterol and that is “Cholesterol”; there is no good cholesterol nor bad cholesterol.

Lipoproteins however have five types and each type has its own function and characteristics. Two of the more popular lipoproteins are LDLs and HDLs. These two popular kinds of lipoproteins are the ones that are usually mistaken by people as bad and good cholesterol.

High Density Lipoproteins (HDL) are lipoproteins that contain the highest proportion of proteins in its make up. Its primary function is to retrieve cholesterol from the tissues within the body and return it to the liver for recycling. Based on this function, it is referred to as the “good cholesterol.”Low Density Lipoproteins (LDL) on the other hand are considered to be “bad cholesterol” because it carries cholesterol from the liver to the tissues.

It is believed that to reduce the risk of heart illnesses, one must maintain high levels of HDL in the body while keeping a low count of LDL that delivers cholesterol to the tissues. This may help reduce the risk of atherosclerosis and other heart related diseases but it is also important to remember that by merely increasing the HDL level in the body is not enough to reduce the risk of heart diseases. What you want is to maintain a high level of “good quality HDL” that will collect the unused cholesterol from the tissues and not just a high level of HDL.

HDL Cholesterol

Apolipoproteins are types or proteins that bind to lipids and create a new substance called “lipoproteins”. This new substance is unique and interesting aside from being an important substance in the body. It’s outer shell is composed mostly of proteins which allows it to be hydrophilic, or water soluble while the inside is lipidic which is compatible with cholesterol and triglycerides.

Since cholesterol is hydrophobic, it cannot travel nor mix with the water based blood stream so it will require a transport to travel from one point in the body to another. The transport that will carry these cholesterol molecules around the body are the lipoproteins. These lipoproteins will absorb cholesterol molecules and store them within tits core as it travels around the blood stream.

There are five known kinds of lipoproteins and all of which have its own characteristics and functions. These lipoproteins are: the Chylomicrons, Very Low Density Lpoproteins (VLDL), Intermediate Density Lipoproteins (IDL), Low Density Lipoproteins (LDL) and the High Density Lipoproteins (HDL). Of the five lipoproteins, the HDL and the LDL are the most popular because of their functions in the body.

The LDL, which carries cholesterols and triglycerides from the liver to the tissues are usually referred to as the “bad cholesterol” while the HDL, which carries cholesterols from the tissues to the liver are referred to as “good cholesterols”.

Now how do these HDLs function?

HDLs, move within the blood stream. As it moves around the body, it collects unused cholesterol from tissues. It will absorb these lipidic substances and store them in its core as it travels around the body. When it starts its rounds, the HDL’s shape is usually flat, but as it picks up cholesterols along the way, this lipoprotein will grow and change in size making it spherical. It will continue to grow as it absorbs cholesterol from the tissues and other lipoproteins. Then the cholesterol that it is carrying will be brought back either to the liver for excretion or recycling or to steroidogenic organs such as the ovaries, testes and adrenals.

One hypothesis which also led to the belief that HDLs are good cholesterols is that HDLs are capable of picking up the lipidic substances from the atherosclerotic areas of the arteries and deliver them back to the liver for excretion.

Based on the process and the function of these HDL molecules, it is obvious and easy to understand why this type of lipoproteins is very important for the body. With HDLs, our body maintains its health by keeping the unused cholesterol moving and preventing them from being rancid. At the same time it has properties that allow it to protect the body from suffering serious heart related illnesses.