Over the past four decades, the evidence has been accumulating that cholesterol
is related to heart disease, particularly angina and heart attacks. Numerous studies
now show that the higher a populations' average cholesterol level, the more frequently
heart disease occurs in that population. For example, populations with very low
cholesterol, such as the Chinese in Mainland China, have an extremely low rate
of heart disease.
Animal studies are also indicative. Rabbits fed cholesterol showed that some
of the dietary cholesterol gets deposited in the arteries, and this is what
causes "hardening of the arteries" and narrowing of the arteries, known as arteriosclerosis
or atherosclerosis. This then results in decreased blood flow to the heart muscle,
which leads to chest pain during exercise or other stresses (angina) and/or
Another link between cholesterol and heart disease is seen in people with inherited
disorders of cholesterol, such as familial hypercholesterolemia. Individuals with
this inherited high level of cholesterol develop heart disease early in life.
For example, if an individual inherits two genes for this disorder, extensive
narrowing of the arteries can occur as early as five to six years of age.
Most importantly, clinical trials using cholesterol-lowering regimens, either
diet or drugs, have shown a significant reduction in cardiac problems, including
angina and heart attack.
The benefit of lowered blood cholesterol in preventing angina and heart attack
has been shown in many large studies. In the Lipid Research Clinic Study,
for every 1% decrease in blood cholesterol, there was 2% decrease in the likelihood
of a heart attack. In people who suffer from angina or have had a heart attack,
lowering of LDL-cholesterol not only decreased the frequency of subsequent episodes
(including stroke) but also increased their overall survival.