Type 2 diabetes mellitus (known as type 2 diabetes for short) is a metabolic disorder in which either the pancreas doesn’t make enough insulin or the cells of the body become resistant to insulin. Your body needs insulin to regulate the levels of sugar (glucose) in your bloodstream.
Type 2 diabetes often goes hand in hand with obesity, high blood pressure and high cholesterol. It used to be known as adult-onset diabetes or non-insulin-dependent diabetes. These terms aren’t used any more, because type 2 diabetes is increasingly affecting younger people and some people with type 2 diabetes have to use insulin.
Insulin is produced in the pancreas, a large, long gland that sits behind your stomach. After you eat a meal, carbohydrates are broken down into glucose and passed into the bloodstream. The pancreas detects the rising level of glucose in your blood (called blood glucose or blood sugar level) and releases insulin.
Insulin helps to take glucose out of the bloodstream by promoting its uptake into fat and muscle cells. Once in the cells, the glucose is used as the energy to fuel the cells doing their different jobs, for instance the muscles working, or is stored in the liver or muscles for use later.
In people with type 2 diabetes one of 2 things goes wrong:
Both of these faults lead to glucose accumulating in the bloodstream. Doctors call this hyperglycaemia. If left untreated, high blood glucose can lead to complications caused by nerve and blood vessel damage, or even death.
Type 2 diabetes doesn’t develop overnight. It usually begins with insulin resistance, where the body’s cells can’t use insulin properly. Glucose builds up in the bloodstream. The pancreas keeps on producing insulin to try and get the blood glucose level down. Over time the pancreas loses its ability to secrete enough insulin. This can sometimes result in the person with type 2 diabetes having to inject insulin every day.
The good news is that because it doesn’t develop overnight, if people at risk of developing type 2 diabetes are identified early enough, they may be able to take measures to avoid it.
This is why having your blood glucose level tested is a good idea. A slightly raised blood glucose level that is above normal, but below the cut off point for a diabetes diagnosis, may be a sign of glucose intolerance or what doctors have named ‘pre-diabetes’. This puts you at risk of developing not only diabetes, but also heart disease.
If you have a slightly raised blood glucose there are things that you may be able to do to try to prevent or delay type 2 diabetes from developing. Doctors have identified lifestyle measures which can often restore blood glucose levels to normal and so avoid type 2 diabetes developing and avoid damage to the heart and circulatory system.
Excess weight (especially weight that's carried around the waist) and fatty tissue seem to contribute to insulin resistance. Weight reduction of 5-7 per cent and getting regular exercise (about 30 minutes of moderately intense activity per day) can help prevent the progression to diabetes in overweight people with glucose intolerance (pre-diabetes). Eating a fibre-rich diet in which less than 30 per cent of total energy comes from fat and less than 10 per cent of energy comes from saturated fat, as well as foods that have a low glycaemic index, can also help.
Taking glucose-lowering medications may also slow or prevent progression to diabetes in people with impaired glucose tolerance.
Diabetes often develops with no symptoms at all or the symptoms are so mild that they go unnoticed. For this reason, blood glucose testing is important because it can highlight diabetes in the making and allow early treatment to avoid complications developing.
The symptoms of diabetes may include:
Type 2 diabetes or insulin resistance often goes hand in hand with central obesity (excess body fat that's concentrated around the waist), high blood pressure and high cholesterol. This cluster of disorders is sometimes known as syndrome X or metabolic syndrome.
Factors that increase a person’s risk of developing type 2 diabetes include:
The aim of treatment of type 2 diabetes is to lower your blood glucose. The first strategies to do this are usually lifestyle changes. Eating healthily, losing weight and getting enough exercise can help to lower blood glucose.
If these lifestyle measures aren’t enough, your doctor may recommend that you take tablets to lower your blood glucose. There are various types of medication to lower blood glucose. They work in different ways: some stimulate your pancreas to make more insulin; others make you more sensitive to insulin; and some decrease the amount of glucose that your liver makes. Some of these tablets have been around for over 30 years. Your doctor may recommend that you take more than one type of tablet if one type alone does not reduce your blood glucose sufficiently.
In some cases your doctor may suggest that you inject insulin as well as take diabetes tablets. This will be if you are not getting good enough control with tablets alone. After a few years some people will need to inject insulin because their bodies will stop making it.
Combining tablets with a healthy eating plan and weight management may mean that you can get by just with tablets and not need insulin injections for a longer time than if you took tablets alone with no lifestyle changes.
You may also need medications to control your blood pressure and the amount of cholesterol and other lipids (types of fats) in your blood. Maintaining a healthy weight, exercising, and eating a healthy diet can also help reduce your need for these extra medications.
Your blood glucose is affected by:
Eating too much food can make your blood glucose go too high. Drinking alcohol without eating any food can make your blood glucose drop too low. Not taking your diabetes tablets or insulin correctly can also lead to your blood glucose going outside of a healthy range.
Ways that you can try to maintain a relatively stable and healthy blood glucose level are:
The glycaemic index (GI) is a scale that gives foods a rating from 0 to 100 depending on how quickly they raise blood glucose levels after they have been eaten. All foods are rated against glucose which scores 100 because it causes blood glucose levels to rise the fastest after it’s eaten.
Foods with low GI values are absorbed slowly and cause blood glucose levels to rise steadily. High GI value foods cause blood glucose levels to rise quickly. Eating low GI foods can help people with diabetes to avoid big peaks and troughs in blood glucose levels. Generally raw, unprocessed foods have a low GI and processed foods tend to be high GI foods.
|Glycaemic index of foods|
|Low GI foods||High GI foods|
|Stone fruits, e.g. peach, cherry||Watermelon|
|Wholegrain bread||White bread|
|Basmati rice||Other white rices|
|Peas, beans, lentils||Potatoes|
|Nuts||Jelly beans, lollies|
Eating low GI foods can also improve sensitivity of the body to insulin, help lower cholesterol and other blood fats, and help people to keep their weight down.
People with diabetes shouldn’t drink alcohol on an empty stomach because the liver will be so tied up trying to metabolise the alcohol, that it won’t do its normal job of putting some glucose back into the bloodstream to raise the blood glucose. The liver’s priority is to clear the alcohol and it won’t produce any glucose until it’s dealt with the alcohol. This can lead to very low blood glucose levels, known as hypoglycaemia.
Last Reviewed: 30 September 2009