Diabetes is a disease that affects the way the body uses food. It is caused by a lack of insulin, which is a hormone made in the pancreas that helps the body’s cells use sugar (glucose) for energy. Insulin is necessary for the body to process nutrients (carbohydrates, fats and proteins), and its absence causes high sugar (glucose) levels in the blood.

There are two types of diabetes:

    • Type 1 diabetes or insulin-dependent diabetes used to be called juvenile diabetes because it usually starts in childhood or during the teen years. It is also sometimes diagnosed in people in their 20s, but diagnosis after age 30 is much less common. It is less prevalent than type 2 diabetes, and the onset is sudden. The condition occurs when the body’s own immune system destroys the insulin-producing cells of the pancreas (called beta cells), in other words, the pancreas stops making insulin altogether.
    • Type 2 or non-insulin-dependent diabetes is a lifelong disease that develops when the pancreas cannot produce enough insulin or when the body’s tissues become resistant to insulin. While the body still makes some insulin, it either doesn’t make enough or the body can’t use it properly. Type 2 diabetes accounts for up to 80 per cent of the diabetes cases in South Africa. The disease usually starts in people who are over 40 years of age, who are overweight – and who may not even realise that they have it.

Some people develop a type of diabetes called secondary diabetes, which is similar to type 1 diabetes. The beta cells are not destroyed by the immune system but by some other factor, such as cystic fibrosis (an inherited disease of the mucus and sweat glands that affects mostly the lungs, pancreas, liver and intestines, sinuses and sex organs), or pancreatic surgery.