Diabetes Explained

This leaflet explains what diabetes is. It also explains the difference between Type 1 diabetes and Type 2 diabetes.


Diabetes Mellitus is a common health condition. About 3.6 million people in the UK have been diagnosed with diabetes, that is about 6 in every 100 people. This figure rises to over 4 million when those as yet undiagnosed are included who don’t know they have diabetes. 

Diabetes Mellitus is a condition in which the amount of glucose (sugar) in the blood is too high because the body cannot use it properly. Glucose comes from the digestion of starchy foods such as bread, rice, potatoes, chapatis, yams and plantain, from sugar and other sweet foods, and from the liver which makes glucose. Insulin is vital for life. It is a hormone produced by the pancreas, that helps the glucose to enter the cells where it is used as fuel by the body for energy.

The main symptoms of untreated diabetes are increased thirst, going to the toilet all the time (especially at night), extreme tiredness, weight loss, genital itching or regular episodes of thrush and blurred vision.

There are two main types of diabetes 

  • Type 1 diabetes
  • Type 2 diabetes (Nine out of ten people with diabetes have type 2) 

Type 1 diabetes develops if the body is unable to produce any insulin. This type of diabetes usually appears before the age of 40. It is treated by insulin injections and diet and regular exercise is recommended. Type 1 diabetes develops when the insulin-producing cells in the pancreas have been destroyed. Nobody knows for sure why this happens but damage to the cells is most likely an abnormal reaction of the immune system that may be triggered by a virus or other infection. Type 1 Diabetes sometimes runs in families suggesting a genetic influence. This type of diabetes generally affects younger people. 

Type 2 used to be called 'maturity onset' diabetes because it usually appears in middle-aged or elderly people, although it does occasionally and increasingly occur in younger people. Type 2 diabetes develops when the body can still make some insulin, but not enough, or when the insulin that is produced does not work properly (known as insulin resistance). This type of diabetes usually appears in people over the age of 40, though it can appear before the age of 40. People who are overweight are particularly likely to develop Type 2 diabetes. It tends to run in families and is more common in South Asian and African-Caribbean communities, where it usually appears in people over the age of 25.

Type 2 Diabetes is treated by diet and exercise alone or by diet, exercise and tablets or by diet, exercise and insulin injections. The main aim of treatment of both types of diabetes is to achieve blood glucose and blood pressure levels as near to normal as possible. This, together with a healthy lifestyle, will help to improve well-being and protect against long-term damage to the eyes, kidneys, nerves, heart and major arteries. Some people wrongly describe Type 2 diabetes as 'mild' diabetes. There is no such thing as mild diabetes. All diabetes should be taken seriously, monitored regularly, and treated properly.

Diabetes UK published a free 'Know your risk?' calculator which calculates your risk of developing type 2 diabetes.

This video also gives a good explanation of “What Causes Diabetes?”

Other causes of diabetes

There are some other much rarer causes of diabetes.

These include:

  • Disorders of the pancreas gland such as chronic pancreatitis
  • Diabetes caused by drugs such as steroids
  • Diabetes as part of another condition such as cystic fibrosis or an endocrine condition like Cushing syndrome
  • Monogenic Diabetes which is associated with a defect in a specific gene usually associated with a very strong family history. Diabetes genes is a great site with loads more information. http://www.diabetesgenes.org.
  • Neonatal Diabetes is a particular type of diabetes occurring before the age of 6 months
  • Latent Onset Automimmune Diabetes of Adulthood (LADA) which is an automimmune condition like Type 1 diabetes but occurs at an older age with a relatively rapid (but not immediate) requirement for insulin, usually within a year of diagnosis, sometime much quicker.
  • Gestational Diabetes is diabetes that occurs in some women during pregnancy then remits after birth. People with gestational diabetes are more likely to develop Type 2 diabetes later in life 

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