HeartPoint: Cholesterol: The Facts

HIGH CHOLESTEROL - The Facts

Read the whole section from beginning to end, or follow these links to specific questions

What is cholesterol?
What causes high cholesterol?
What happens if I lower my cholesterol?
Can you tell me a good diet?
But I follow my low-fat diet really closely. Why is my cholesterol still high?
What is a normal cholesterol level?
What should my level be? (Take this test)
How often should my cholesterol be checked?
Does it matter when my cholesterol and triglyceride levels are measured?
My level of cholesterol is normal. Does that mean I can’t have a heart attack or stroke?
What about triglycerides?

Like high blood pressure, high cholesterol (hypercholesterolemia) itself is not a disease, but a condition that can lead to some very important consequences, among them heart attack and stroke.. You can’t tell how high your cholesterol is without a blood test. You don’t feel bad just because the level of cholesterol in your bloodstream is high.

Remembering our goals at HeartPoint, while we'll spend a lot of time talking about different aspects of cholesterol, let's remember these important points throughout our discussion:

There is no question that increasing levels of cholesterol in the blood are associated with an increased risk of blockages of the arteries (arteriosclerosis and atherosclerosis). The evidence which has been found over the years is compelling.

More recent, but no less compelling, information definitely indicates that many people can lower their risk back towards normal with proper treatment of their cholesterol levels.

There is no single "right way" to deal with high cholesterol levels, but every program should include attention to diet and exercise. In addition, there are many safe and effective medications which have come on the scene in recent years for people who need more than diet and exercise.

That not to say that there's not a lot of controversy about how to lower cholesterol, the right diet, when to use medications and which ones, etc. But let’s not allow the controversy to obscure the fact that there’s plenty to do to help. With this in mind, we can go on and learn some more about this interesting and important topic.

What is cholesterol?

Cholesterol is a type of fat, one which is very important for life. It is a vital building block of many substances including the cell membrane of every cell in our body, digestive "bile" released by the gall bladder, the "sex hormones", Vitamin D (associated with calcium metabolism) and other important substances.

It is a waxy sort of substance when cooled. About one tablespoon circulates in the bloodstream at any one time. There are actually multiple types of molecules which make up the "total cholesterol" commonly measured.

Cholesterol is not all bad. We have to have some cholesterol, but the liver can make as much as we need. If the level is too high, it can be deposited in tissues, specifically the arteries, causing them to narrow and not carry enough blood to vital organs such as the brain or the heart. It can also weaken the artery, causing it to enlarge and produce an aneurysm. This process is termed "arteriosclerosis", and abnormal blood lipids (fats) including cholesterol are very important in its formation.

Cholesterol is not only present in the foods we eat, but our liver produces our own supply of cholesterol as well. It is primarily responsible not only for the manufacture of cholesterol, but regulating the proteins ("lipoproteins") which carry it.

It is tempting to think that cholesterol is a material which kind of "filters out" into the walls of the blood vessels, and the higher the amount of cholesterol in the blood, the more that will be deposited in the arteries. It is quite a bit more complicated than that. Depositing cholesterol in the walls also has to do with factors that injure the lining of the blood vessels, such as smoking with its many potent toxins such as carbon monoxide. Other stresses, such as high blood pressure likewise can disrupt the normal function and structure of the vessels, allowing the build-up of blockages primarily composed of cholesterol.

There are different types of cholesterol, or at least different molecules that carry it. Cholesterol itself cannot dissolve in the bloodstream, and needs proteins to "carry" it around. "Bad" cholesterol is that which is carried on a molecule called "LDL" (for "low-density lipoprotein"), and which has the tendency to release cholesterol into the tissues, including the vessel walls. A smaller molecule, "HDL" (for "high-density lipoprotein") is also called "good" cholesterol because it can bring cholesterol back from the tissues to the liver. The higher the level of HDL and the lower the level of LDL, the less likely it is someone will develop blockages (no levels guarantee it, though!).

Cholesterol which is "oxidized" is far more toxic than cholesterol which isn’t. Oxidized cholesterol causes an inflammatory response in the vessel wall, allowing for more cholesterol deposition. This inflammatory response can be important in the development of heart attacks. Even if the therapy of high cholesterol didn’t lower your blood level, and even if it didn’t remove the cholesterol from the vessel walls, if it just changed the type of cholesterol in the wall to a non-oxidized state, it would do a lot of good.

Armed with this knowledge, we can try to answer some of the more common questions that are posed by patients.

What causes high cholesterol?

There are several other diseases (specifically, diabetes and some forms of thyroid, liver, and kidney diseases) that can cause high cholesterol, and your physician should check for these as part of the evaluation. Some medications can alter the levels of cholesterol and/or triglycerides.

However, it is most frequently caused by a combination of diet and genetic factors built in to a person’s make-up. Even patients with "great genes" for cholesterol metabolism can overwhelm the system by pursuing an inactive lifestyle, gaining an imprudent amount of weight, and eating a high fat diet. Many more people don’t even need to try very hard to get a high cholesterol because their livers don’t handle even a moderate amount of saturated fat and cholesterol intake well.

The importance of diet is shown most clearly by studying groups of people who migrate from their lands of origin, and its culture and diet. The Japanese who have moved to America have been well studied. Japanese people who remain in Japan and follow the more "heart healthy diet" continue to show a low incidence of heart disease. Those who come to Western cultures and adopt our style of eating have a prompt and definite increase in their cholesterol level. This is closely followed by an increase in their frequency of heart disease. In other words, their genes didn’t change, but their diets did!

What happens if I lower my cholesterol?

Here’s some great news – Every 1% reduction in your cholesterol reduces your risk by 2%. Every 1 mg/dL (not percent) increase in your good cholesterol lowers your risk 2-5%. Time to get with it!

Can you tell me a good diet?

We’ll do our best. Follow the link Low Fat Diet

But I follow my low-fat diet really closely. Why is my cholesterol still high?

It is a shame that some people try so hard, yet never get desired results. It is really important to realize that the nature of some people’s problem with cholesterol is one that simply does not completely normalize even with the best of diets. Many patients have a defect in the enzymes in the liver that regulate cholesterol properly. In addition to diet and exercise, they may require medications to help achieve more optimal cholesterol levels.

What is a normal cholesterol level?

When discussing cholesterol levels, it is more appropriate to realize that there is a spectrum of risk: that is, your level is not "normal" or "abnormal". Rather, the higher the level of cholesterol, the higher the risk of developing a problem. Furthermore, as we noted earlier, it’s important to take into account whether the person has other risk factors which makes the level of cholesterol more dangerous, if they have already developed blockages.

It’s more reasonable to talk about "desirable" levels of cholesterol. Experts disagree on exactly what numbers should be used, but this is a public health and statistical question. For the individual patient, the lower your level, the lower your risk of coronary artery disease and other forms of arteriosclerosis.

The NCEP (National Cholesterol Education Program) was formed to help define public health policy in this area. This group of experts hashed out a huge variety of questions regarding cholesterol with an eye towards what was best for most people. In a document of this size, designed for public and not individual health, there is bound to be controversy. However, many extremely reasonable conclusions and recommendations were made. It is helpful to note their recommendations regarding cholesterol levels.
For the population as a whole:
Desirable (less than 200)
Borderline (200-239)
High (greater than or equal to 240)

Patients with established atherosclerotic disease, other risk factors, or high levels should have decisions based on their LDL cholesterol (take the test below).

What should my level be? (Take this test)

It depends . . .

Everyone should aim for an HDL of greater than 35 mg/dL.

If you have known coronary artery disease, angioplasty or bypass surgery, your LDL levels should be less than 100 mg/dL (this generally corresponds to a total cholesterol of 150-170 mg/dL).

If you don’t have established arteriosclerotic problems, add up how many "risk factors" you have:

___ I am a smoker
___ I have high blood pressure
___ I have diabetes
___ I am a male 45 years or older
___ I am a female 55 years or older
___ I am female less than 55 years with premature menopause without replacement estrogen therapy.
___ I have a family history of early heart disease (a male parent or sibling less than 55 years old, or female parent or sibling less than 65 years old)
___ My HDL level of cholesterol is less than 35 mg/dL.

If your HDL level of cholesterol is greater than 60 mg/dL, then subtract one.

Okay. If you have less than two risk factors, then your goal LDL is less than 160 mg/dL. This corresponds to a total cholesterol of about 240 mg/dL. This is a pretty high cholesterol, and should be re-evaluated in about 1 year. LDL levels greater than 190 mg/dL are a real concern.

If you have two or more risk factors, then your goal LDL is 130 mg/dL, corresponding to a total cholesterol of about 200 mg/dL. Take good care of your other risk factors and follow a good diet. Since you have several risk factors, follow-up with cholesterol levels every year. LDL levels greater than 160 mg/dL are a real concern in this group.

How often should my cholesterol be checked?

Even in people without heart disease or high cholesterol, it is recommended that the level be treated every 5 years. Some groups should be checked every 1-2 years. There is probably little benefit from being checked every 2-3 months unless one is under some sort of intensive therapy.

The one I don’t understand is the person who has high levels of cholesterol, will not modify their diet, and declines medications. Despite this, they want their level checked every 2 months, "just to see how things are doing". Why check if you’re not going to do anything about it?

Does it matter when my cholesterol and triglyceride levels are measured?

The most reproducible measurements are those that are obtained after a period of not taking anything in but water (a 12-14 hour fast is best). However, cholesterol is not extremely sensitive to the foods you have just eaten, and non-fasting samples may be adequate for screening purposes. Fasting samples may be required for the most accurate measurements in people with borderline or high levels, or for patients on certain types of therapy for their cholesterol. Triglycerides do show significant changes with what was eaten at the most recent meal, and are more accurate when measured in the fasting state.

Realize too that after a heart attack, within minutes of its onset, the cholesterol level can change. It is often falsely low, and remains so for 3-6 months. Likewise, recent surgery or other major illness may throw the level off.

My level of cholesterol is normal. Does that mean I can’t have a heart attack or stroke?

Unfortunately, no. The lower the level, the lower the risk of heart attack, stroke or other manifestations of arteriosclerosis. However, there are other factors which determine that risk. Furthermore, there is more than one cause for heart attacks or strokes.

In short, everyone is at risk – it’s just that some are more at risk than others. Try to be in the lower risk group by following a good diet, exercise, and (if necessary) medication program!

What about triglycerides?

Triglycerides are another type of fat that is associated with adverse health consequences. Many patients with high cholesterol also have high triglycerides. It is therefore difficult to see if the triglycerides create their own effect, or if all of the increase in problems with arteriosclerosis are simply due to the fact that high triglycerides go along with the high cholesterol.

The studies go back and forth. It is not surprising – the metabolism of lipids in general and triglycerides in particular is quite complex Triglycerides themselves certainly do not get deposited in vessel walls, a point which should seem to indicate they aren’t very important in the overall scheme of atherosclerosis. However, they are carried on many of the same molecules (lipoproteins) as cholesterol, and this would argue that they must be exerting some influence. It is clear that for most people, triglycerides are not nearly as important as cholesterol in causing arteriosclerosis. It seems to be more important in women and patients with diabetes.

Normal fasting levels are generally less than 200 mg/dl. Medications are rarely indicated for levels under 400 mg/dl.

High triglycerides can cause other important health problems. Although it is usually caused by other health problems, pancreatitis is a serious inflammatory condition of the pancreas which can be caused by marked elevations of triglycerides (usually over 1000 mg/dl).

Triglyceride levels are strongly influenced by diet. While cholesterol levels remain pretty constant over a month or so, and aren’t terribly effected by meals, triglycerides respond quickly to a meal, particularly one with a lot of fat, sugar, or alcohol. While a non-fasting cholesterol level still gives reasonable information, triglyceride levels need to be determined after not eating for 8-12 hours to be accurate (or at least reproducible). Furthermore, patients with high triglycerides need to be particularly careful about their diets.

While we generally don’t worry as much about high triglyceride levels as we do about cholesterol. Patients who have arteriosclerosis with high triglycerides as their only obvious abnormality of fat metabolism may need to be approached differently, however. And, it is important for other causes of high triglycerides need to be looked for. It is not always only due to diet or the patient’s genes. It may be associated with other health conditions.

The treatment for high triglycerides (hypertriglyceridemia) is similar to that for high cholesterol. Recommendations are found on the section on treatment. Treatment of High Cholesterol

�COPY;1997 HeartPoint Updated September 1997

There’s really a lot more if you’re still interested in discovering it --Links to Cholesterol section

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