Cholesterol: Hero or Villain?
By Hans Diehl, M.D. www.chiphealth.com
Cholesterol: You Need It, but... What can turn a normal, needed, healthful substance into a dangerous killer? How can something that makes sex hormones, helps build strong bones, and balances the body's stress response also choke off oxygen and damage vital organs and tissues?
Cholesterol is both hero and villain. While we cannot live without cholesterol, in excessive amounts it can kill us.
The blood cholesterol level is the single most important factor in determining a person's risk for heart disease, the nation's number one killer. For instance, a person with a total blood cholesterol level of 260 mg% (6.8 mmol/L) is four times more likely to have a fatal heart attack than is a person with a cholesterol of less than 220 mg% (5.6 mmol/L). And 220 is far from ideal! Every 10% rise in blood cholesterol is accompanied by a 30% rise in heart attack risk.
Doesn't Heredity Determine Cholesterol Level?
Very few people have genetic cholesterol disorders. The vast majority of blood cholesterol levels is determined by dietary factors. Depending on what we eat, cholesterol levels can go up or down substantially even within a couple of weeks.
How Does High Cholesterol Cause Heart Attacks?
It does it by gradually narrowing the vital heart-nourishing arteries through a process called atherosclerosis, which is followed by a hardening of the arterial wall due to calcification.
Most heart attacks are related to plaques, which are made up mostly of cholesterol and fat. Plaques are like tire patches. They are the body's response to damaged areas in arterial walls which may be caused by free radicals, especially those found in oxidized cholesterol. The body responds to the irritation by adding more and more 'patches' to protect the area, causing the plaque to slowly enlarge. But in doing so it also chokes off the blood flow and may eventually obstruct the artery completely.
When blood cholesterol levels are under 150 mg% (3.8 mmol/L), initial arterial damage usually heals quickly and the scars shrink. But when cholesterol levels edge past 180 (4.6 mmol/L), LDL-cholesterol begins to attach itself to the vessel walls, causing atherosclerosis (thickening, narrowing, stiffening, and plaque formation).
Massive studies of world populations have documented the fact that the total blood cholesterol levels, in general, are the most dependable predictor of arterial obstructions resulting from plaque formation. Lately, however, the emphasis has shifted towards the pivotal role LDL cholesterol plays, which ideally should be kept below 90 mg% (2.3 mmol/L). Research on migrant groups of people confirms that this is not so much a disease of genetics as it is a disease of lifestyle. When people who have been protected by a simple diet move into a Westernized culture with its dietary excesses, their blood cholesterol levels go up and soon they begin developing the same arterial diseases as Westerners.