The role of insulin in the body

It may be easier to understand the importance of insulin therapy if you understand how this naturally occurring hormone usually works in the body and what happens if you have diabetes.

If you don't have diabetes, insulin helps:

• Regulate blood sugar levels. After you eat, carbohydrates break down into glucose, a sugar that is the body's primary source of energy. Glucose then enters the bloodstream. The pancreas responds by producing insulin, which allows glucose to enter the body's cells to provide energy.
• Store excess glucose for energy. After you eat — when insulin levels are high — excess glucose is stored in the liver in the form of glycogen. Between meals — when insulin levels are low — the liver releases glycogen into the bloodstream in the form of glucose. This keeps blood sugar levels within a narrow range.

If you have diabetes:

Your glucose levels will continue to rise after you eat because there's not enough insulin to move the glucose into your body's cells. People with type 2 diabetes don't use insulin efficiently (insulin resistance) and don't produce enough insulin (insulin deficiency). People with type 1 diabetes make little or no insulin.

Untreated, high blood glucose can eventually lead to complications such as blindness, nerve damage and kidney damage.