What Is the Role of Insulin?

The main role of insulin, a hormone, is to help the body use the glucose that it takes in from food sources for energy or to store it as glycogen in the liver. Insulin is produced by special cells called “beta cells” inside the pancreas. The hormone acts as a key that allows glucose to enter the body’s cells, where it is used for energy. If the body doesn’t produce enough of the hormone, sugar remains in the blood stream and the cells begin to starve.

The body makes all of the different types of sugars that it ingests into simple sugars, mainly glucose. This sugar is the main source of energy to nearly every process in the body. While most cells do rely on glucose for their energy, cells in the brain and nervous system cannot function at all unless the body’s glucose levels remain steady. When sugars are ingested and glucose is produced, insulin is responsible for helping the body balance its blood sugar levels.

The blood glucose levels in the body typically rise after a meal. When insulin is working properly, the pancreas secretes the hormone to lower those levels. The more the person eats, the higher the level of hormone released. Most of the glucose is stored as glycogen for later use. When blood sugar levels drop, another pancreatic hormone, glucagon, tells the liver to convert some of the glycogen back to glucose and release it into the blood stream.

When the mechanism is working in balance, the level of glucose in the blood remains stable. Sugar is processed, stored, and released precisely when needed. When a disruption to the process causes glucose levels to rise, the body tries to compensate by increasing insulin production and eliminating some of the excess glucose though the urine. If the pancreas is not secreting enough of the hormone, as in patients with diabetes, the chronically high levels of glucose in the blood can damage several of the body’s organs, including the eyes, kidneys, nerves, heart, and blood vessels.

There are two types of diabetes. In type 1, the pancreas completely stops making insulin due to the destruction of the beta cells. Patients with this type require daily insulin injections to help process the glucose. In type 2, the pancreas still produces some of the hormone, but the body no longer responds to it properly. Type 2 diabetes can be treated with medications that help the body use insulin better, or insulin shots if needed. Several types of shots are available, with some working faster than others. A physician determines the type of injection used based on the patient's needs.