What
is cholesterol?
Cholesterol, one of the groups of fats in the
blood called lipids, is a word we have all heard many times, especially, since
it was established that cholesterol was one ofthe most important factors in the
development of coronary heart disease (CHD).
Cholesterol
is a small molecule but despite this has been so intensively studied that by 1985
it had been the subject of 13 Nobel prizes.
In
the 1980s there was considerable reluctance to treat cholesterol abnormalities,
however in 1994 evidence became available that lowering cholesterol reduced the
incidence of heart attacks, strokes and the devlopment of angina and lowered overall
mortality. Since that time there has been unprecedented growth in the prescription
of medicines to lower cholesterol.
Is cholesterol bad for you?
Cholesterol is bad for you
is a statement most people would accept. In fact, cholesterol is essential for
life and we could not live without it, but problems arise when cholesterol levels
in the blood are too high.
How
can there be 'good' cholesterol and 'bad' cholesterol? They sound contradictory
but there is a very important distinction.
"Good"
cholesterol (or HDL cholesterol) makes up about 20% of the blood cholesterol.
It is know known that high levels of HDL Choleserol gives some protection against
cardiovascular disease but low levels of HDL Cholesterol increase the risk of
cardiovascular disease.
"Bad"
cholesterol (or LDL cholesterol) can be deposited in blood vessels leading to
narrowing and blockage. If this happens in one of the coronary (heart) arteries
it can cause a heart attack or if it occurs in an artery to the brain it can cause
a stroke.
Cholesterol
and Triglyceride is a fat that always circulates in the blood, especially after
a meal high in saturated fat.
High
triglyceride levels are associated with obesity, diabetes, low HD cholesterola
dn high LDL choelsterol.
Triglyceride
levels can be lowered by:
Some
people, (about 1 in 500), have very high levels of bad cholesterol. This runs
in families and is due to an inherited gene, which disturbs the way LDL cholesterol
is removed from the blood. This is called familial hypercholesterolaemia (FH).
Where
does cholesterol come from?
The body produces its own supply
of cholesterol, mainly in the liver, but lesser amounts can come from the diet
in foods of animal origin such as meat, dairy products and eggs. Thre are two
groups of fat, namely unsaturated fat and saturated fat. saturated fat is often
visible and solid at room temperature (e.g. fat on meat).
Unsaturated
fat include monosaturated fats, polysaturated fats and omega-3 fats and our diet
should contain equal amounts of these. However, a Western diet usually contains
a lot more saturated fat than the other kinds of fat.To eat healthily we not only
have to reduce the quantity of fat we eat but more importantly our diet should
contain the right porportions of the correct kind of fat.
The
following chart summarises the effects of the different groups of fats: