What is diabetes?

Diabetes is a disorder caused by insufficient or lack of production of insulin (a hormone) by the pancreas (a gland in the abdomen). Insulin is responsible for absorbing glucose (a simple sugar) into the bloodstream, where it is available for body cells to use for growth and energy.

When most people eat, the pancreas automatically produces the correct amount of insulin to absorb the glucose. In people with diabetes the pancreas either produces little or no insulin, or the body's cells do not respond to the insulin that is produced. Glucose builds up in the blood, overflows into the urine and passes out of the body, with the result that the body loses its main source of fuel.

If untreated, diabetes can cause blindness, heart disease, strokes, kidney failure, nerve damage and birth defects in babies born to women with diabetes. There are two major forms of diabetes — type 1 diabetes and type 2 diabetes. Both types of diabetes tends to run in families, although only 10% of type 1 patients will have a family history of diabetes; in type 2 diabetes, this figure rises to 30%.

Type 1 diabetes

Also known as insulin-dependent diabetes (IDDM), this type is most often seen in children or young adults, although the disorder can appear at any age. Type 1 diabetes occurs when the body produces little or no insulin. Usually the cause of this type of diabetes is not known, but it can sometimes be due to a viral infection, injury of the pancreas or an immune system disorder.

Type 2 diabetes

Also known as non insulin-dependent diabetes (NIDDM), this is the most common type of diabetes — 90%—95% of people with diabetes have type 2 diabetes. In type 2 diabetes the pancreas usually continues to produce some insulin, but for some reason, the body cannot use the insulin effectively. It is most common in adults over the age of 40 and in people who are overweight or have high blood pressure. It has been linked with the Western lifestyle, since it is most common among overweight people and those who do not get enough exercise.

Other types of diabetes

Gestational diabetes — also known as pregnancy diabetes - usually develops or is discovered during pregnancy. The diabetes generally disappears after the birth, although women who have had gestational diabetes are at increased risk of developing type 2 diabetes later in life.

What are the symptoms of diabetes?

People with type 1 diabetes usually develop symptoms over a relatively short period. Symptoms in people with type 2 diabetes are not as noticeable as in type 1. Type 2 symptoms are often diagnosed by chance through routine medical check-ups. Symptoms vary from person to person, but common symptoms include:

  • Increased urination.
  • Increased appetite or loss of appetite.
  • Excessive thirst.
  • Visible weight loss.
  • Blurred vision.
  • Recurrent skin infections.
  • Fatigue.
  • Vaginal infections or infections of the foreskin in uncircumcised men.
  • Slowly healing sores.

How is diabetes diagnosed?

Diabetes is diagnosed by examining glucose levels in blood samples using one or more of the following tests:

  • Random glucose test — a glucose level above 11.1mmol/L taken at a random time on two occasions is a diagnosis of diabetes.
  • Fasting glucose test — a glucose level above 7.8mmol/L measured without anything to eat and on two different days is a diagnosis of diabetes.
  • Glucose tolerance test — a blood glucose test is taken two hours after a glucose drink is given to the patient. A level above 11.1mmol/L is a diagnosis of diabetes, while a level below 7.8 is normal.

How is diabetes treated?

While dietary control and an organised exercise programme are important for both types of diabetes, the medications used are different. Type 1 diabetes will require insulin treatment. Type 2 diabetes may be sufficiently controlled by diet and exercise alone. If medications are required, it is usually treated with oral glucose-lowering tablets (oral hypogylcaemics). Occasionally, those with type 2 diabetes will need insulin treatment.

Insulin therapy

Insulin therapy is the main treatment for type 1 diabetes. It may also be required by some people with type 2 diabetes.,

The aim of insulin therapy is to control the amount of insulin in the bloodstream so that glucose levels are normal or near normal. You will be put on insulin and begin to regulate your diet as soon as the diagnosis is confirmed.

As well as self-injections of insulin every day, you should also check your blood sugar level every day to ensure you get the right dosage of insulin — if you have too much or too little sugar in your blood, you will need to change your diet or the amount of insulin you are taking to keep your blood sugar at a healthy level.


Diet is important in both type 1 and type 2 diabetes, but in type 2 diabetes effective dietary management may be sufficient to control the disorder. The main aim is to maintain a normal blood sugar level.

Your doctor will advise you about which foods you should eat and how to space your meals to avoid going too long without food. The number of calories you are allowed is determined by whether you need to maintain, lose or gain weight.

Your doctor may refer you to a dietician to help you plan a diet that includes a lot of carbohydrates and high-fibre food, and minimises the intake of sugar-rich foods. If you are overweight, you will be advised to lose weight — losing as little as a few pounds can reduce your need to take medication.


Exercise is very important both type 1 and type 2 diabetes. A good exercise programme can help to control your blood sugar level. However, you may need to adjust your insulin dose according to the amount of exercise you take, as too much insulin and exercise may lower your blood sugar level.

Oral medications

Oral medications lower the blood sugar by increasing the amount of insulin secreted by the pancreas or by increasing the action of insulin in the body or by delaying the absorption of glucose. These drugs are called hypoglycaemic tablets. They will not be effective unless they are combined with dietary restrictions.

Routine check-ups

  • The aims of routine check-ups are to check that treatment is progressing satisfactorily and to optimise your treatment to help to prevent complications. If any complications are present, they will be monitored and treated.
  • Your doctor may want to see you every three to six months to check the amount of HbA1c (long-term glucose) in your blood and take your blood pressure, evaluate your home glucose readings, and discuss your diet and exercise.
  • You will also have other regular checks including the lipid (fat) levels in your blood, urine tests for protein (albuminuria), blood tests for kidney function, eye examinations and regular examinations of your feet.

How do hypoglycaemic reactions (‘hypos’) occur?

People with diabetes being treated with insulin or some of the oral hypoglycaemic tablets must be careful about maintaining blood glucose levels. If you have stimulated your system with insulin or tablets, blood glucose will continue dropping until you have some food in the form of carbohydrates. The symptoms of low blood pressure (hypos) include tiredness, feeling hungry or feeling generally unwell. You may also feel dizzy or confused and you may sweat. If blood sugar levels drop too low, you could go into a diabetic coma. Avoiding ‘hypos’ is a key part of a diabetic treatment programme and this programme will be geared to the individual. To help prevent hypos, people at risk are advised to monitor their blood or urinary sugar levels regularly. As a precaution against an attack of hypoglycaemia, people with type 1 diabetes should carry some sugar or glucose with them at all times.

What are the complications of diabetes?

Complications are more likely if the diabetes has not been well controlled — studies have shown that good glucose control can significantly reduce the likelihood of complications occurring. Late-stage complications do not usually develop for 10—15 years in type 1 diabetic patients. In type 2 diabetes symptoms can appear close to the time of the diagnosis because the disease may have been undetected for a long time. Complications can include:

  • Low blood sugar levels leading to weakness, confusion and sometimes seizures and loss of consciousness.
  • Susceptibility to infections.
  • Ulcers and infections of the feet.
  • Arteriosclerosis (hardening of the arteries), particularly in smokers and those with high blood pressure.
  • Diabetic nephropathy (kidney disease).
  • Diabetic retinopathy (diabetes-related eye disease).
  • Diabetic neuropathy (nerve damage).

What can I do to maintain good health?

If you have type 1 diabetes:

  • Learn how to use your home blood glucose testing kit and use it regularly — this will enable you to measure your blood glucose levels and control your insulin dose.
  • Learn how to give yourself insulin injections — you are going to need them for the rest of your life.
  • If you smoke, quit.
  • Follow the diet advised by your doctor and eat at regular times.
  • Exercise regularly and eat more or decrease the insulin you are taking to prevent low blood sugar levels.
  • Carry some form of sugar so that you can treat low blood sugar quickly and a protein snack to make sure you eat as often as you should.
  • Visit your doctor regularly so that your blood glucose levels can be checked and your eyes, kidneys and feet examined for signs of any late stage diabetic symptoms.
  • Tell your doctor if you feel ill or if you have been diagnosed with another disease.
  • Carry identification (such as a card or bracelet) that says you have diabetes, in case of an emergency.

If you have type 2 diabetes:

What is the outlook?

If you have type 1 diabetes:

Type 1 diabetes is a lifelong condition, but, if treated effectively, you will reduce the risk of developing late-stage diabetic complications.

If you have type 2 diabetes:

Type 2 diabetes is also a lifelong condition, but it can usually be controlled with a combination of diet and medication, although as the disease progresses, you may find that you also need insulin injections to minimise the risk of further complications.

Back to top of page