What are islet cells?
Diabetes – or diabetes mellitus – is a common condition in which the amount of glucose (sugar) in the blood is too high because the body is unable to use it properly. This is because the body's method of converting glucose into energy is not working as it should.
Normally, a hormone called insulin carefully controls the amount of glucose in our blood. It helps the glucose to enter the cells where it is used as fuel by the body. Islets are the cells that produce insulin within the pancreas (see illustration), a gland that lies just behind the stomach.
We obtain glucose from the food that we eat, either from sweet foods or from the digestion of starchy foods such as bread or potatoes. The liver can also make glucose.
After a meal, the blood glucose level rises and insulin is released into the blood. When the blood glucose level falls – for example, during physical activity – the level of insulin falls. Insulin, therefore, plays a vital role in regulating the level of blood glucose and, in particular, in stopping the blood glucose from rising too high.
There are two main types of diabetes:
- Type 1 diabetes
- Type 2 diabetes
Type 1 diabetes develops when there is a severe lack of insulin in the body because most or all of the cells in the pancreas that produce it have been destroyed. This type of diabetes usually appears in people under the age of 40, often in childhood. It is treated by insulin injections and diet.
Type 2 diabetes develops when the body can still produce some insulin, though not enough for its needs, or when the insulin that the body produces does not work properly. This type of diabetes usually appears in people over the age of 40, though in South Asian and African-Caribbean people it often appears over the age of 25. However, recently, more children are being diagnosed with the condition, some as young as seven. Type 2 diabetes is treated by diet alone, or by a combination of diet and tablets, or by a combination of diet and insulin injections.