All About Fats (Page 2)
Cholesterol is essential in small quantities for brain and nerve cells
and for hormones. Some cholesterol comes ready-made in animal foods
but most is made in the body. It is the body’s excess synthesis of
cholesterol that causes problems. When the diet is high in saturated
fats, more cholesterol is made. Excess cholesterol in the blood, leads
to clogged arteries, especially the arteries to the heart and brain.
Cholesterol can also block blood vessels to the penis and is the major
physical cause of impotence in men.
Cholesterol is made up of both HDL cholesterol (high density
lipoprotein) and LDL cholesterol (low density lipoprotein). HDL
cholesterol is ‘good’ and represents cholesterol being taken back from
the tissues to the liver. LDL cholesterol is ‘bad’ and correlates with
fatty deposits in the arteries.
Ideally, blood cholesterol levels
should be less than 5.0-5.5mmol/L. The higher is the percentage of
HDL cholesterol the better. Those from long-lived families, young
women and endurance athletes tend to have high HDL cholesterol
levels, generally ranging from 25 to 40 per cent of the total. Most
men and most post-menopausal women have HDL levels less than 20 per
cent of the total.
How to lower your cholesterol Level
Saturated fats lower protective HDL cholesterol and increase the nasty
LDL type. Polyunsaturated fats reduce the bad LDL cholesterol and are
preferable to saturated fats. Monounsaturated fats can reduce the bad
LDL cholesterol and may raise the good HDL cholesterol. These fats are
therefore best. They are found in olive or canola oils, avocado and
nuts such as almonds.
In trying to reduce blood cholesterol, many people make the mistake of
avoiding foods that contain cholesterol (such as eggs) while
continuing to eat foods that contain saturated fats. For example,
changing from animal fats to vegetable fats may not reduce your intake
of saturated fat if the vegetable fat is still saturated, as many are.
The best way to reduce your blood cholesterol is to avoid saturated
fats and lose any excess weight. Stress can also be a factor in
raising blood cholesterol levels.
We convert excess fats, alcohol and sugar into triglycerides. After a
meal, the level of triglycerides in the blood rises. Those not used
for energy are tucked away in fat depots. If the blood level of
triglycerides is still high after a 12-hour fast, it shows the body is
not clearing fats properly. This may occur in those with a
predisposition to diabetes. High triglyceride levels mean the blood
is fatty and the heart must work harder.
The small quantity of fat in most fish is rich in omega 3 fatty acids.
These are chemically different from the omega 6 fatty acids in
margarines and many varieties of vegetable oils.
The omega 3 fatty acids can prevent blood clots forming, make blood
less "sticky", lower blood pressure and triglyceride levels, and can
play a role in reducing inflammation in some kinds of arthritis and
eczema. They are also vitally important in the retina of the eye and
in the development of the brain.
Omega 3 fatty acids are found in all sea foods. Some also occur in
some seeds and green vegetables, although the conversion of these to
the same longer-chain omega 3 fats found in fish does not occur
efficiently if the diet is too high in omega 6 fats.
Ideally, we should have some omega 6 fats and some omega 3 fats.
Currently we have about 50 times as much of the omega 6s as the omega
3s. The ideal ratio is thought to be closer to 6 parts of omega 6s to
one of omega 3s. In practice, this means eating less margarine and
polyunsaturated vegetable oil and more fish. One to three fish meals a
week is ideal. Some of this should be fresh fish; some can be canned.