MEDICAL SURFARI: KNOW YOUR CHOLESTEROL

By now you have probably heard of "the good cholesterol" and "the bad cholesterol." I am referring to the storybook version of the beneficial and detrimental effects of cholesterol. I remember some years ago when I was studying for my master's degree, my major professor, a comparative endocrinologist, returned from seeing his physician for a general checkup.

This included a blood test to measure his lipid (fat) blood levels, which in turn included testing his various cholesterol levels.

As he told me the story he chided this man for presenting an embarrassingly over-simplified, storybook version of lipid physiology describing his cholesterol as "the good cholesterol" and "the bad cholesterol." A few years later I read a medical essay in a supplement to the Mayo Clinic Health Letter. It stated, "My doctor gave me the results of my cholesterol test. He said, Your good cholesterol is low that is bad, and your bad cholesterol is high that is bad too. You need to raise your good and lower your bad that would be good.'"

I believe that this sort of explanation is not only insulting to the intelligence of the listener, it is nothing less than confusing. Since that time I vowed that I would never resort to the "good and bad cholesterol" storytelling.

Cholesterol is a waxy lipid that serves as an essential building material throughout your body to build cell membranes and to insulate your nerves.

In addition, it is the backbone molecule of certain hormones and it is also the backbone molecule of bile acids produced by your liver, which help you digest your food. About 80 percent of your blood cholesterol is produced in your liver and about 20 percent comes from your diet, consequently the amount of fat and cholesterol you eat may influence blood lipid levels including your blood cholesterol levels.

For fats to be transported through your blood vascular system they must be coated with protein and this coated molecule is referred to as lipoprotein.

Lipoproteins are responsible for transporting blood lipids, cholesterol and triglycerides in your blood vascular system. Lipoproteins that carry these lipids may vary in density and some are called low-density lipoproteins (LDLs) whereas others are called high-density lipoproteins (HDLs) and there are very-low-density lipoproteins (VLDL) as well. LDLs bind to the surface of cells but if they are not used by the cell they may saturate it with cholesterol, and this may in turn become deposited within the walls of the cells lining your arteries resulting in plaques that cause atherosclerosis (narrowing and blockage of the artery).

Enlarging plaques may cause the inner lining of your artery to become rough, which may in turn cause a blood clot to form that severely narrows the caliber of the blood vessel or completely plugs it, preventing blood flow.

When this occurs in one of the blood vessels in your heart, it results in a heart attack. If it occurs in part of your brain, it results in a brain attack, or stroke. So your blood cholesterol levels are important because this is a significant risk factor for heart blood vessel disease, which is still the No. 1 killer of Americans. Your risk for heart and brain blood vessel disease can be significantly lowered by keeping your cholesterol levels within normal ranges.

One of the ways the body keeps cholesterol from damaging blood vessels is by circulating HDLs, which pick up unused LDLs attached to the surface of cells thereby preventing these from becoming deposited. In fact, the ratio of LDL and HDL is very important and in some cases more attention is being paid to the HDL level to be certain that it is high enough to scavenge the excess LDLs. The only way to know if your blood lipids are in the desirable range is to have a blood test after you have fasted overnight. Your family physician or specialist can order this test and help you interpret the results.

WORLD WIDE WEB

Resources: www.americanheart.org/cld/ This Web site, provided by the American Heart Association discusses, the different types of cholesterol and methods in cholesterol reduction.

www.mayohealth.org/mayo/9306/htm/choleste.htm This Web site, provided by the Mayo Clinic, provides information on what cholesterol is, ways to reduce cholesterol levels, and problems associated with high cholesterol.

www.pharmico.com/disease/cardio/atpsum.html This Web site, provided by the National Institutes of Health, provides information on detection, evaluation, and treatment of elevated cholesterol.