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© Dirk Biddle
Cholesterol is a lipid that is essential for life. It forms the membranes for cells in all organs and tissues in the body. A small amount of the body's cholesterol circulates in the blood in complex particles called lipoproteins. Measurement of lipoprotein levels is used to estimate the risk of developing heart disease. Increased values may indicate a tendency toward hardening and/or blocking of the arteries due to plaque deposition (atherosclerosis). When the arteries feeding the heart become blocked, a heart attack may occur. If the arteries that go to the brain are affected, then the result may be a stroke.
Cholesterol in itself is not all bad, in fact our bodies need a certain amount of this substance to function properly. However, when the level gets too high, vascular disease can result. There are three major kinds of cholesterol: High Density Lipoprotein (HDL), Low Density Lipoprotein (LDL) and Very Low Density Lipoprotein (VLDL).
i) HDL (high density lipoprotein) cholesterol is a ‘good cholesterol’ as it protects against heart disease by helping remove excess LDL cholesterol deposited in the arteries. High levels seem to be associated with low incidence of coronary heart disease. Conversely, low levels are associated with increased risk of coronary heart disease.
ii) LDL (low density lipoprotein) is a type of lipoprotein that carries cholesterol in the blood. LDL cholesterol is considered "bad cholesterol" because LDL cholesterol deposits form in the arteries when blood LDL levels are high, contributing to hardening of the arteries. There are two ways to report LDL. The most common is simply an estimate calculated from Total Cholesterol, HDL and triglyceride results (This may be stated as "LDL Calc" on a report). However, a directly measured LDL Cholesterol is usually more accurate, but it is also more expensive and may require that your doctor specify the direct LDL.
iii) VLDL (very low density lipoprotein) is another carrier of fat in the blood. VLDL is composed mostly of cholesterol, with little protein. VLDL is also often called a ‘bad cholesterol’ because it deposits cholesterol on the walls of arteries. Increased levels of LDL and VLDL are associated with atherosclerosis and coronary heart disease.
iv) Triglyceride is fat in the blood which, if elevated, has been associated with heart disease, especially if over 500 mg. High triglycerides are also associated with pancreatitis. Triglyceride levels over 150 mg/dl may be associated with problems other than heart disease. It has also been noted that whenever triglycerides are increased, HDL cholesterol decreases.
Ways to lower triglycerides include a) weight reduction, if overweight, b) reduce animal fats in the diet: eat more fish, c) take certain medications your physician can prescribe, d) get regular aerobic exercise, e) decrease alcohol and sugar consumption—alcohol and sugar are not fats, but the body can convert them into fats then dump those fats into your blood stream, and f) restrict calories - carbohydrates are converted to triglycerides when eaten to excess.