Diabetes mellitus is a common disease that interferes with the body's ability to store energy from food. The pancreas makes a substance called insulin that helps to store energy from food. In type 2 diabetes mellitus (also called adult-onset diabetes), the body makes plenty of insulin but is unable to use it normally. The result is high blood sugar levels that, over time, can lead to complications that include blindness, kidney failure, nerve damage, and heart disease. Fortunately, good care to keep blood sugar under control can prevent the development of these complications. The control of blood pressure also is extremely important in preventing diabetes complications and death.