LDLs, called the "bad" cholesterol, carry cholesterol to the body's cells, where it can be stored, woven into the cell membranes, or used to make vitamin D or steroid hormones. LDL isn't "bad" because of this activity. However, it's considered "bad" when the body's cells don't accept the LDL, and it remains in the bloodstream.
Only certain types of cells accept cholesterol from LDLs. These cells have special structures called receptors located on the surface of their membranes that are responsible for pulling in the cholesterol from the LDLs. A large number of these receptors are found on the surface cells of the liver; the rest are found on a variety of other cells in the body.
When these cells have taken up all the cholesterol they can manage for use, the number of receptors shrinks to decrease the amount of cholesterol entering the cell. Any extra LDL cholesterol then remains in the blood. This is where the danger to your heart lies. The LDLs take the unused cholesterol and deposit it in the walls of your arteries as plaque, causing a condition known as coronary atherosclerosis.
A person who has a high total blood-cholesterol level usually has a high level of LDLs. Several studies have shown that a high level of LDLs is an independent risk factor for coronary heart disease. An independent risk factor is a trait, condition, or habit that is associated with an increased chance of developing a disease, regardless of whether other traits or conditions are present.
In one study, when scientists looked at the arteries of young people who had died from causes other than heart disease, they found that the victims who had high levels of LDL cholesterol also had more fatty buildup in their arteries.
Further evidence of the role of LDLs comes from studies of the Pima Indians. Although obesity and diabetes are common among the members of this group, they have low total cholesterol levels, low LDL-cholesterol levels, and low rates of coronary heart disease.
Studies of families with an inherited defect that causes high LDL levels also implicate LDLs as the key to coronary heart disease risk. In an informative study of 116 families with familial hypercholesterolemia (inherited high cholesterol) conducted by the National Institutes of Health, family members who had the defect not only had a higher risk of coronary heart disease than unaffected family members, but their coronary heart disease occurred an average of 20 years earlier.
Studies of both diet and drug therapy have shown that lowering LDL-cholesterol levels decreases the risk of coronary heart disease. If you want to lower your risk of coronary heart disease, lowering your level of LDLs is the place to start.
Of course, LDLs aren't the only important kind of cholesterol. High levels of HDL cholesterol can lower the risk incurred by high levels of LDL cholesterol. Learn why on the next page.
This information is solely for informational purposes. IT IS NOT INTENDED TO PROVIDE MEDICAL ADVICE. Neither the Editors of Consumer Guide (R), Publications International, Ltd., the author nor publisher take responsibility for any possible consequences from any treatment, procedure, exercise, dietary modification, action or application of medication which results from reading or following the information contained in this information. The publication of this information does not constitute the practice of medicine, and this information does not replace the advice of your physician or other health care provider. Before undertaking any course of treatment, the reader must seek the advice of their physician or other health care provider.