Does lowering LDL cholesterol prevent atherosclerosis and heart attacks?

Both heredity and diet have a significant influence on a patient's LDL, HDL and total cholesterol levels. For example, familial hypercholesterolemia (FH) is a common inherited disorder whose victims have a diminished number or nonexistent LDL receptors on the surface of liver cells.

The resultant decreased activity of the LDL receptors limits the liver's ability to remove LDL cholesterol from blood. Thus, affected family members have abnormally high LDL cholesterol levels in the blood. They also tend to develop atherosclerosis and heart attacks during early adulthood.

Diets that are high in saturated fats and cholesterol decrease the LDL receptor activity in the liver, thereby raising the levels of LDL cholesterol in the blood. Fats are classified as saturated or unsaturated according to their chemical structure. Saturated fats are derived primarily from meat and dairy products and can raise blood cholesterol levels. Some vegetable oils made from coconut, palm, and cocoa are also high in saturated fats. On the other hand, most other vegetable oils are high in unsaturated fats. Unlike saturated fats, unsaturated fats do not raise blood cholesterol and can sometimes lower cholesterol. Olive and canola oil are high in monounsaturated fats, which may have a protective effect against coronary heart disease. Unfortunately, some vegetable oils are converted to saturated fats during a process called "hydrogenation" which can be required for food processing.

Does lowering LDL cholesterol prevent atherosclerosis and heart attacks?

In the past 10 years, clinical trials have conclusively demonstrated that lowering LDL cholesterol reduces heart attacks and saves lives. The benefits of lowering LDL cholesterol include:

• Reducing the formation of new cholesterol plaques;
  
• Eliminating existing plaques;
  
• Preventing rupture of existing plaques;
  
• Decreasing the risk of heart attacks; and
  
• Lowering the chance of strokes.
  

How low should LDL cholesterol be?

The National Cholesterol Education Program (NCEP) has issued LDL cholesterol treatment guidelines for adults. The NCEP target levels are different for people who have varying risks for heart attacks. For example, since individuals who have already suffered a heart attack have a greater chance of experiencing another heart attack than individuals without known coronary heart disease, their LDL cholesterol levels need to be more aggressively lowered than people without known coronary heart diseases.

In July 2004 the NCEP (National Cholesterol Education Program) issued a new set of guidelines for treatment of high blood cholesterol in adults. Please read the New Cholesterol Guidelines article for more information.