Diabetes is a serious medical condition characterized by high levels of glucose in the blood.

Glucose is a simple sugar that comes from the food you eat. When your stomach digests food, glucose is absorbed into the bloodstream. The glucose circulates in your blood and serves as the main source of fuel for all the cells in your body.

All cells in the body need a continuous supply of energy to carry out normal body functions. Glucose, a simple sugar derived from the foods we eat, is the primary source of cellular energy. Glucose is transported throughout the body by the bloodstream.

However, glucose cannot get inside cells by itself. Glucose needs insulin, a hormone produced by the pancreas, to transport it from blood into cells.

The pancreas is a gland that lies behind the liver and stomach.

Diabetes occurs when the pancreas either can't produce any insulin at all, can't produce enough insulin, or the body can't use the insulin it makes. When any of these happens, glucose builds up in the blood. This is a condition known as hyperglycemia. The result is that the body lacks the fuel it needs.

  • Type 1 diabetes -- Usually starts in childhood and accounts for 5 - 10% of all diagnosed cases of diabetes. People with type 1 diabetes produce little or no insulin and therefore must use insulin daily to control their condition.
  • Type 2 diabetes -- Usually starts in adulthood, although it is being diagnosed more often in children because of rising rates of childhood obesity. The symptoms can be subtle. Many people don't even know they have type 2 diabetes. It is much more common than type 1, accounting for 90 - 95% of cases. People with type 2 diabetes are resistant to the insulin the body makes. Type 2 diabetes is often controlled with diet and exercise, and sometimes oral drugs or insulin.
  • Gestational diabetes -- Some women develop this form of diabetes when they are pregnant. Gestational diabetes usually goes away after the baby is born, but the woman is then at higher risk for developing type 2 diabetes later in her life.

Want to know all the different names for diabetes? (It's a little confusing, so feel free to skip this!)


American Diabetes Association. Diagnosis and classification of diabetes mellitus. Diabetes Care. 2007;30(suppl 1):542-547.

McDermott MT. Endocrine Secrets. 4th ed. St. Louis, MO: Mosby; 2004.


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Review Date: 5/10/2007

Reviewed By: Robert Hurd, MD, Professor of Endocrinology, Department of Biology, Xavier University, Cincinnati, OH. Review provided by VeriMed Healthcare Network.

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