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Health
Fats
and Cholesterol
The
Good The Bad and The Healthy Diet
"Eat
a low-fat, low-cholesterol diet." Most of us have heard
this simple recommendation so often over the past two decades
that we can recite it in our sleep. Touted as a way to lose
weight and prevent cancer and heart disease, it's no wonder
much of the nation - and food producers - hopped on board.
Unfortunately,
this simple message is now largely out of date. Detailed
research -much of it done at Harvard - shows that the total
amount of fat in the diet, whether high or low, isn't really
linked with disease. What really matters is the type of
fat in the diet.(1) Bad fats increase the risk for certain
diseases and good fats lower the risk. The key is to substitute
good fats for bad fats.
And
cholesterol in food? Although it is still important to limit
the amount of cholesterol your eat, especially if you have
diabetes, dietary cholesterol isn't nearly the villain it's
been portrayed to be. Cholesterol in the bloodstream is
what's most important. High blood cholesterol levels greatly
increase the risk for heart disease. But the average person
makes about 75% of blood cholesterol in his or her liver,
while only about 25% is absorbed from food. The biggest
influence on blood cholesterol level is the mix of fats
in the diet.
<>The
Cholesterol--Heart Disease Connection<>
Cholesterol is a wax-like substance. The liver makes it
and links it to carrier proteins called lipoproteins that
let it dissolve in blood and be transported to all parts
of the body. Why? Cholesterol play essential roles in the
formation of cell membranes, some hormones, and vitamin
D.
Too
much cholesterol in the blood, though, can lead to problems.
In the 1960s and 70s, scientists established a link between
high blood cholesterol levels and heart disease. Deposits
of cholesterol can build up inside arteries. These deposits,
called plaque, can narrow an artery enough to slow or block
blood flow. This narrowing process, called atherosclerosis,
commonly occurs in arteries that nourish the heart (the
coronary arteries). When one or more sections of heart muscle
fail to get enough blood, and thus the oxygen and nutrients
they need, the result may be the chest pain known as angina.
In addition, plaque can rupture, causing blood clots that
may lead to heart attack, stroke, or sudden death. Fortunately,
the buildup of cholesterol can be slowed, stopped, and even
reversed.
Cholesterol-carrying
lipoproteins play central roles in the development of atherosclerotic
plaque and cardiovascular disease. The two main types of
lipoproteins basically work in opposite directions.
Low-density
lipoproteins (LDL) carry cholesterol from the liver to the
rest of the body. When there is too much LDL cholesterol
in the blood, it can be deposited on the walls of the coronary
arteries. Because of this, LDL cholesterol is often referred
to as the "bad" cholesterol.
High-density
lipoproteins (HDL) carry cholesterol from the blood back
to the liver, which processes the cholesterol for elimination
from the body. HDL makes it less likely that excess cholesterol
in the blood will be deposited in the coronary arteries,
which is why HDL cholesterol is often referred to as the
"good" cholesterol.
In general,
the higher your LDL and the lower your HDL, the greater
your risk for atherosclerosis and heart disease.
Source:
www.hsph.harvard.edu/nutritionsource
Copyright
(R) thedailystar.net 2004
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