Cholesterol

If you have high cholesterol, you’re not alone. About half of all Australian adults have cholesterol levels that are considered too high. Even if you don’t know what your cholesterol levels are, if you’re overweight (as three in five adults are) or sedentary (as two in five adults are), then it’s more than likely that your pattern of cholesterol and other blood fats is out of balance.

What is cholesterol?

Although cholesterol has been given a bad rap over the years, it’s not by itself a bad thing.

Cholesterol is a soft, waxy substance that occurs naturally in cell walls and membranes throughout your body, including your brain, nerves, muscles, skin, liver and heart. It’s one of several fats, or lipids, that your body produces. Without enough cholesterol, you simply could not live. You use cholesterol to produce sex hormones (including oestrogen and testosterone), vitamin D, and bile acids that help you digest fat.

However, you need only a relatively small amount to take care of all of these things. And your body (your liver, intestines and even skin) manufactures about three or four times more cholesterol than most Australians eat.

As with so many things, cholesterol isn’t bad for you unless there’s too much of it. The story isn’t quite that simple, however. There are different kinds of cholesterol, some bad, some good. And how much you have of each makes a big difference to your likelihood of developing coronary heart disease (CHD).

It’s actually not cholesterol per se that’s good or bad for you, but the “vehicle” through which it travels in your bloodstream. Because cholesterol is waxy, it can’t mix with blood, which is watery. Like oil in a salad dressing, it remains separate. To enter the cells and tissues where it’s needed, then, it hooks up with proteins, creating special transporters called lipoproteins. Think of these as submarine-like bubbles that carry cholesterol around the body. Some of these “submarines” are friends, but most are foes.

Low-Density Lipoprotein

Low-density lipoproteins, or LDLs, are the primary foes – the archenemies, in fact. LDLs carry most of the cholesterol (75% to 80%) in the blood, depositing it into the cells, including the arteries. There, these particles contribute to the formation of plaque, which narrows the arteries.That reduces the amount of blood that can get through, diminishing the oxygen that reaches the heart.

Some LDL types are more dangerous than others. Smaller, denser LDL particles are more damaging to blood vessels because it’s easier for them to cross the lining of the vessel and burrow into the vessel wall.

So what’s the ideal LDL level? That depends on your risk factors for CHD. But if you’re a man aged 45 or older or a woman 55 or older and don’t have CHD, diabetes, hypertension, or a family history of premature CHD, and don’t smoke, here’s what you should aim for (levels are measured in millimoles per litre, or mmol/L).

Everything from your weight to whether or not you smoke to your family health history – even the amount of stress you’re under – affects your LDL level. Of course, your diet makes a difference, too – particularly the types of fat you eat.