by Olwen Anderson

Created on: February 20, 2009   Last Updated: February 21, 2009

Why should you be worried if your doctor sternly informs you that you have high cholesterol, and that it must be reduced, or you will be prescribed cholesterol lowering medication for life? After all, you feel fine. Alas, a test result of 'high cholesterol' means that there is a silent time bomb ticking in your arteries, counting down towards a heart attack unless you take action.

HOW DID THIS HAPPEN?

Your body needs cholesterol. Your liver is constantly creating lipoproteins, molecules containing protein and cholesterol. They transport hormones; make protective insulation for nerve endings, and help form cell membranes.

LDL cholesterol ('bad' cholesterol) is produced by your liver and despatched in search of storage sites. If there are none available, the cholesterol will be deposited on your artery walls.

HDL cholesterol ('good' cholesterol) acts like a vacuum cleaner, removing excess cholesterol from your artery walls and returning it to your liver for disposal through bile and faeces.

Making sure you have more HDL cholesterol than LDL cholesterol is the key to maintaining healthy cholesterol levels.

WHY IS FAT PASTED ON THE ARTERIES NEAR MY HEART?

It seems unfair that when arteries narrow due to fat deposits on the walls, it's the large arteries near your heart that are affected most. There's a reason for this.

In your blood vessels, the blood flowing through small capillaries is quite slow. Blood cells and molecules gently bump against capillary walls as they move along. When leaving the heart however, blood is under enormous pressure.

Blood cells and molecules in this area crash into your artery walls with great force, sometimes enough to cause damage to artery walls. This is known as 'shear stress'. Damage can result to the endothelium, the inner lining of your artery, and a lesion (wound) forms. This lesion attracts immune cells as well as LDL molecules. As the artery wall repairs itself, it may try to build a new endothelium over the lesion. This repair process creates toxic chemicals, trapping lipid (fat) molecules, cholesterol deposits, immune components and toxins within an atherosclerotic 'plaque'.

Major problems can result if all or part of that atherosclerotic plaque detaches from your artery wall, releasing a torrent of lipids (fats), pro-thrombotic immune components, and toxic chemicals. Most fatal coronary events have been traced back to one or more of these plaques breaking apart.

IT DOESN'T HAVE TO BE THIS WAY

If the balance of your cholesterol is good (more HDL than LDL), and your body's oxidative stress load is under control, HDL lipoproteins will remove fat molecules from your artery walls. Your body's normal healing mechanisms will repair damage done in the original lesion, and the artery will remain wide and clear.

SYMPTOMS OF HIGH CHOLESTEROL

Alas, high cholesterol is completely silent until your arteries clog up enough to start interfering with blood flow to your heart. This is why a check of your cholesterol level every year or so is a good idea; particularly if there is a history of heart disease, stroke or atherosclerosis in your family.

Some people with disorders of lipid metabolism develop xanthelasma, slightly raised, yellow tinted cholesterol deposits on their eyelids. These are not necessarily a definitive diagnosis of high cholesterol they can also be a symptom of hypothyroidism and kidney problems; but certainly warrant professional investigation.

Don't ignore a test result of 'high cholesterol'. It may be silent, but it's a ticking time bomb that you need to defuse.

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