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Understanding Diabetes

Cholesterol

CheeseButterMeat and eggs

What is Cholesterol?

Cholesterol is a type of fat which is produced within the body. It is also found in the diet, as a component of 'animal fat' such as butter, cheese and meats. It has a variety of functions including the formation of some essential hormones. We need cholesterol for day to day life but you can have too much of a good thing.

Why is a high cholesterol level bad?

If you have too much cholesterol in the blood, it ends up as fatty deposits in your blood vessels known as 'atheroma'. This increases your risk of angina, heart attacks, strokes and circulatory problems. When the fatty deposits get too big, they can block off a small blood vessel, causing damage.

Studies on large numbers of people have shown that people with higher blood cholesterol levels tend to suffer from coronary heart disease more often. The MRFIT study which examined more than 360,000 men aged 35-57 showed that the risk of heart disease increased appreciably when cholesterol exceeded 6.5 mmol/l and rose steeply when cholesterol rose above 7.8 mmol/l.

Please read the separate page on atheroma for more information.

What are the various type of fats in the blood?

Like all other fats, cholesterol does not ‘dissolve’ in the blood. Fats are carried in the blood bound to special proteins. These proteins act as carriers or transporters. They are known as lipo-proteins (fat + proteins).

Your doctor may measure LDL cholesterol, HDL cholesterol which are lipoproteins as well as Triglycerides.

Are all these fats equally dangerous?

There are two main types of cholesterol - LDL cholesterol or 'bad' cholesterol and HDL cholesterol or 'good' cholesterol. HDL cholesterol takes excess cholesterol away from blood vessels and transports it to the liver. Ideally you should have a low LDL ('bad') cholesterol level and a high HDL ('good') cholesterol level. A low level of HDL cholesterol conversely, will increase your risk of heart attacks. This is why these subtypes of cholesterol are measured by your doctor.

What is the normal level of cholesterol?

There is no 'normal' level of cholesterol which is considere to be universally healthy. A cholesterol level which is not considered dangerous for you may require treatment in someone else. Whether your cholesterol concentration is considered high or not depends on your age, sex, blood pressure and whether you smoke. It also depends on whether you already have angina or a previous heart attack when doctors will advise, you should have a cholesterol level of less than 5 mmol/l.

Why do I have high cholesterol?

Many different factors influence your levels of cholesterol and you will be glad to hear it is not all a question of diet.

  1. Genetic factors - high cholesterol runs in families. You cannot change your parents so there is not a great deal you can do to modify this particular risk !
  2. Diet - eating too much 'saturated' fat (found in animal fat) and cholesterol (also found in animal fat).
  3. Exercise - regular exercise can lower your cholesterol. Exercise can also increase your levels of 'good cholesterol' (HDL)
  4. Age and sex
  5. Weight - reducing weight can help improve your cholesterol concentrations

Will lowering my cholesterol prevent heart problems?

Yes, many large scale research studies using thousands of volunteers have shown this to be true. It is also important to pay attention to other risk factors such as high blood pressure and smoking. Lifestyle changes such as diet and exercise help as well. People who have already had a heart attack are at greater risk of a second attack. Lowering your cholesterol using a 'statin drug' will greatly reduce your risk of having a further heart attack.

I'm not keen on tablets, is improving my diet adequate treatment for high cholesterol ?

Diet is certainly important in controlling your cholesterol. A healthy diet may reduce your cholesterol concentrations by 5-10% at most. However, if your levels are high to start with, it is unlikely that dieting is going to make a big difference. A combination of diet and tablets, works best. You may have heard of the terms 'saturated fat' and 'polyunsaturated fat'. In general terms, more saturated fat in the diet helps to raise the blood cholesterol level and relatively more polyunsaturated fat helps to reduce cholesterol. Changing the amount of cholesterol in your food affects your cholesterol levels to a much lesser extent than does changing the ratio of 'polyunsaturated to saturated' fats.

How is a high blood cholesterol treated?

The statins are the main group of cholesterol lowering medication. They work by blocking a chemical enzyme known as HMG-CoA reductase. This has the effect of lowering blood cholesterol. Since the body produces more cholesterol during the night, it is best to take this medication at night.

What can I do to help reduce my cholesterol ?

Lifestyle changes may help to lower your cholesterol. These include:

  • low saturated fat Diet
  • weight loss if overweight
  • regular physical exercise
  • even if you begin drug treatment you should continue with these lifestyle changes.

What are the cholesterol lowering drugs available?

 

 

strength

simvastatin

ZocorR

10, 20 & 40 mg

pravastatin

LipostatR

10, 20 &, 40mg

atorvastatin

LipitorR

10, 20 &, 40mg

fluvastatin

LescolR

20 & 40 mg

What are the side effects of these drugs?

Statins are usually safe and free of major side effects in most patients.

The common side effects are gastrointestinal - constipation, abdominal pain or cramps. These symptoms usually subside with time.

Anyone on a statin experiencing muscle aches or dark coloured urine, should contact their doctor. The most serious and rare side effect is breakdown of muscle known as 'rhabdomyolysis'.

What precautions should be taken to avoid side effects?

  • void drinking too much alcohol when taking statins
  • you should have blood tests to check on your liver function from time to time
  • if you get muscular weakness, cramps or pain whilst taking these tablets, inform your doctor

How does alcohol affect cholesterol?

A regular intake of alcohol leads to an increase in good (HDL) cholesterol. This is not a good reason to take up alcohol!

 

Dr Nishan Wijenaike, Consultant Physician
West Suffolk Hospitals Diabetes Service.
Revised: October 2007