Type 1 diabetes occurs when the body's immune system attacks and destroys certain cells in the pancreas, an organ about the size of a hand that is located behind the lower part of the stomach. These cells -- called beta cells -- are contained, along with other types of cells, within small islands of endocrine cells called the pancreatic islets. Beta cells normally produce insulin, a hormone that helps the body move the glucose contained in food into cells throughout the body, which use it for energy. But when the beta cells are destroyed, no insulin can be produced, and the glucose stays in the blood instead, where it can cause serious damage to all the organ systems of the body.
For this reason, people with type 1 diabetes must take insulin in order to stay alive. This means undergoing multiple injections daily, or having insulin delivered through an insulin pump, and testing their blood sugar by pricking their fingers for blood six or more times a day. People with diabetes must also carefully balance their food intake and their exercise to regulate their blood sugar levels, in an attempt to avoid hypoglycemic (low blood sugar) and hyperglycemic (high blood sugar) reactions, which can be life threatening.
