Look after your Cholesterol

Having cholesterol is often assumed to cause heart disease. In reality a number of factors like cigarette smoking, high blood pressure, being overweight, not taking enough exercise, age and family history are more relevant risk factors. Having a high cholesterol level does not cause symptoms and most people only find out they have high cholesterol during health checks or when health problems have actually happened.

Cholesterol is a natural fatty substance, known as a lipid, mostly made by the liver and needed for a multitude of purposes including the manufacture of cells, the stimulation of hormone production and the absorption of certain vitamins from food. It is transported around the body in the blood by being attached to a protein. This fat-protein combination is known as a lipoprotein. Lipoproteins can be:

1. High density (HDL)
2. Low density (LDL)
3. Very low density (VLDL)

The difference between each type of lipoprotein all depends on how much protein there is in relation to fat.

• About 70% of cholesterol is transported around the body as LDL and is mostly fat and not much protein. LDL causes cholesterol to be deposited in the arteries narrowing blood flow and is sometimes referred to as ‘bad cholesterol’.
• About 20% of cholesterol is transported as HDL which is mostly protein and actually helps prevent cholesterol building up in the arteries. HDL is sometimes referred to as ‘good cholesterol’.
• About 10% are triglycerides. These are a different type of fat which mostly comes from fat in the food we eat when calories that are not used immediately are converted into triglycerides and transported to fat cells for storage. Triglycerides are carried in the blood as very low density lipoproteins (VLDL).

The main risk associated with a high concentration of low level cholesterol is that blood vessels can narrow with fatty deposits called plaques. This can result in angina (chest pain) if blood supply to heart muscle is reduced, a heart attack if the blood vessel to the heart is completely blocked and/or the development of other health problems according to which blood vessels are becoming narrowed or blocked. These include ‘Stroke’ if the blood supply to the brain is reduced or leg pain and leg ulcers if blood supply to the lower limbs is reduced.

Cholesterol is measured in units called millimoles per litre of blood, usually shortened to mmol/l. It is desirable to have a total cholesterol level under 5mmol/l and a LDL that is under3 mmol/l. The ‘European Atherosclerosis Society’ has produced the following guide to cholesterol levels:

CHOLESTEROL LEVEL	MEANING
Less than 5 mmol/l	An acceptable level
Between 5 mmol/l and 6.5m.mol/l	Mildly increased
Between 6.5mmol/l and 7.8m.mol/l	Moderate increase
Greater than 7.8m.mol/l	Significant increase

When cholesterol is above 5mmol/l, you should reduce the total amount of fat that you eat and increase the fibre content of your diet. This can be achieved by cutting down your intake of saturated fats from dairy products and by increasing your consumption of cereals, vegetables and fruit.

Quantities of cholesterol that are greater than 6.5 mmol should be made known to your GP who will consider a fasting blood test to look at the ratio between total cholesterol and HDL (‘good cholesterol’) called the TC: HDL ratio.

The overall aim of lowering cholesterol is to reduce the risk of heart disease. The type of treatment depends on the overall risk. There are two main ways. The first is a healthy lifestyle – exercising on most days, eating a low fat diet, not smoking and drinking alcohol within the recommended limits. The second is to combine lifestyle changes with cholesterol lowering medicines known as statins.

For further information visit the British Heart Foundation website www.bhf.org.uk