Are Your Cholesterol Numbers Normal?

Many people believe that a common theory that suggests cholesterol causes cardiovascular disease is really just a myth, so there is no need to monitor your cholesterol numbers at all. The truth is, however, that  your cholesterol  levels play a big role and are critical to the process of atherogenesis that clogs your arteries up. The very same cholesterol that causes these clogs in your ateries, however, is not the cholesterol that is usually measured.

What Exactly Is Cholesterol?

A surprising amount of people don't know much about what cholesterol even is. Most people think of Cholesterol is usually described as a fatty, waxy substance. This is not exactly true, however. The kind of cholesterol that runs in our bloodstreams is actually something quite different.

Fats do not dissolve in water. Therefore, cholesterol could not properly be transported through the bloodstream except for being coated with proteins that are water-soluble. Without a balloon-like layer of lipoprotein, cholesterol could never enter your circulation.

The body is made up of about 85% of the cholesterol in circulation, the other 15% comes from the food you eat. The basic building blocks of cholesterol are triglycerides, which basically store your unused carb calories as a substance called glycerol, combining both of these with unused fatty acids. Triglycerides can be broken down into fuel, or the liver can process them into smaller, protein-coated particles of cholesterol. Cholesterol is not just one thing , but there's many different types. Not all kinds of cholesterol function in the same way in the human body.

What Are the Different Kinds of Cholesterol?

When we get our cholesterol numbers checked out, we are usually told our total cholesterol levels. Total cholesterol is (1) a fatty substance that has to be coated with protein to circulate through the bloodstream but is not (2) a triglycerides. The lab measures your total level of both lipids and triglycerides, and what's left is cholesterol. 

The "balloon" of protein coating cholesterol, however, may be of various sizes. The lightest, fluffiest, largest particles of cholesterol are known as very low-density lipoprotein or VLDL cholesterol. As the VLDL cholesterol circulates through the body and its glycerol and fatty acids are used to fuel your muscles and internal organs, it shrinks into a slightly denser form known as low-density lipoprotein or LDL cholesterol. 

The liver can still extract more fatty acids and glycerol from LDL cholesterol to make high-density lipoprotein or HDL cholesterol. But why exactly does the size of cholesterol even make a difference?

Some particles of cholesterol are too large to get trapped in the linings of your arteries. Others are too small. LDL cholesterol is what is known as the "bad" cholesterol that can contribute to the process of calcification. However, not even every kind of LDL cholesterol is harmful to your body. Only the just-large-enough pieces of cholesterol known as apoliprotein B1 (or apo-B1) is capable of "unlocking" your white blood cells in the linings of  your arteries so that they fill up with cholesterol and eventually calcify into the plaques that  are known for blocking your arteries.

Neither triglycerides nor any of the other various forms of cholesterol is always good or bad for you. The process of plaque formation depends on more than just the presence of cholesterol, even the kind of cholesterol that can get trapped in the lining of an artery matters.

What Is A Healthy Cholesterol Level?

One of the realities of cholesterol measurement is that some people who have "low cholesterol," referring to total cholesterol, will develop cardiovascular disease, and some people who have "high cholesterol" will not.

Don't Take LDL Readings at Face Value

That is also true of LDL levels. LDL actually is not measured by lab tests. It is estimated. The lab measured total lipids, triglycerides, and HDL cholesterol. VLDL and LDL cholesterol are not measured.

As a rule of thumb, VLDL cholesterol is estimated as 1/5 of triglycerides, and then the "bad" cholesterol is calculated with a simple mathematical formula:

LDL = Total lipids - HDL - triglycerides - (1/5 of triglycerides)

Since LDL is an estimate, however, measurement can go wrong. If you go on a diet, your body has fewer excess carbohydrates and fatty acids to store as triglycerides. When the lab is simply applying the formula rather than directly measuring LDL cholesterol (a test that typically costs an additional $500 or so in the USA and is not available in other countries because of cost), lowering triglycerides artificially inflates the LDL number.

It is not unusual for people to be told they have "borderline high cholesterol," go on a diet, and then be told they need medication. The test simply does not take into account good behavior. There are similar problems when diabetics get their triglycerides down by lowering their blood sugar levels. 

This means that lab values for LDL tend to be higher than true values. But it isn't "LDL" that causes cardiovascular disease.

When LDL Levels Are Not "Normal"

Many commentators believe that since "LDL" is not really the cause of cardiovascular disease, and the lipoprotein apo-B1 that actually causes heart disease is not usually measured, then it is OK to ignore cholesterol. This turns out not to be a good idea.

While LDL is not the precise cause of heart and blood vessel disease, it turns out that apo-B1 goes up and down in a relatively tight relationship to the measurement of total LDL. If you have high LDL, especially if you have high triglycerides, then steps to manage your cholesterol (such as taking a statin drug) actually are a good idea.

What is a safe and normal cholesterol level, then? Since cholesterol is not the only factor in the development of cardiovascular disease, normal levels of cholesterol vary. Here are some good guidelines:

• If you smoke, if you have diabetes, if you have had heart disease, or if a close family member has had heart disease, an LDL level of 190 mg/dl or more indicates a need for immediate treatment. An LDL level of 160 mg/dl also requires treatment, probably with smaller doses of statin drugs. Getting LDL down to 70 mg/dl or lower is optimal.

• If you do not have any risk factors for heart disease, then you probably won't be treated for high cholesterol as long as your LDL is 160 mg/dl or lower.

However, LDL cholesterol is just one factor in heart disease. Triglycerides are another. Even if you have good LDL and total cholesterol levels, many doctors will put you on statin drugs if your triglycerides are over 150 mg/dl, even if your cholesterol levels are normal.

The cholesterol myth is just a myth. Cholesterol levels really do make a difference in whether you get heart disease. While it is best if your doctor orders measurements of apo-B1, high LDL cholesterol levels also require medication.