What is cholesterol?

Without cholesterol your body wouldn't work:
it's vital to ensure the body's normal function.
Like specialised bricks, it forms part of the outer membrane that surrounds every cell.
It's used to insulate nerve fibres (and so make nerve signals travel properly) and make hormones,
which carry chemical signals around the body.

Too much cholesterol in the blood, however, increases the risk of coronary
heart disease and disease of the arteries.


Cholesterol and food

One of the biggest misconceptions people have is that food's packed with cholesterol.
In fact, very little cholesterol is found in foods.
The main culprits are eggs, offal and shellfish.

What's important is the type of fat in the food you choose,
especially saturated fat. Once inside the body, the liver turns this fat into cholesterol.


Lipoprotein levels

Knowing your cholesterol level isn't, on its own,
enough to tell you what your personal risk of heart disease is.

You also need to know about lipoproteins.
These are special molecules that carry or transport cholesterol around the body.

There are three main types:

* Low-density lipoprotein (LDL) - often known as bad cholesterol.
It carries cholesterol from the liver to the cells and,
if supply exceeds demand, can cause harmful build-up of cholesterol.

* High-density lipoprotein (HDL) - or good cholesterol.
This takes cholesterol away from the cells and back to the liver, where it's either broken down or excreted.
* Triglycerides.


The greatest danger is when someone has high levels of LDL cholesterol and trigylcerides, and low levels of HDL cholesterol.