Diabetes is a chronic disease that occurs when the pancreas is unable to produce insulin or when the body is unable to make good use of the insulin it produces. In the blood, all carbohydrate foods are broken down into glucose. Insulin aids in the passage of glucose into the cells. High blood glucose levels are caused by the inability to manufacture or use insulin properly (known as hyperglycaemia). Long-term high glucose levels are linked to organ and tissue failure, as well as harm to the body's internal organs and tissues.