Insulin is a hormone that is responsible for allowing glucose in the blood to enter cells, providing them with the energy to function. A lack of effective insulin plays a key role in the development of diabetes.
Hormones are chemical messengers that instruct certain cells or tissues to act in a certain way that supports a particular function in the body.
Insulin is essential for staying alive.
we look at how the body produces insulin and what happens when not enough of it circulates, as well as the different types that a person can use to supplement insulin.
Insulin is a chemical messenger that allows cells to absorb glucose, a sugar, from the blood.
The pancreas is an organ behind the stomach that is the main source of insulin in the body. Clusters of cells in the pancreas called islets produce the hormone and determine the amount based on blood glucose levels in the body.
The higher the level of glucose, the more insulin goes into production to balance sugar levels in the blood.
Insulin also assists in breaking down fats or proteins for energy.
A delicate balance of insulin regulates blood sugar and many processes in the body. If insulin levels are too low or high, excessively high or low blood sugar can start to cause symptoms. If a state of low or high blood sugar continues, serious health problems might start to develop.
In some people, the immune system attacks the islets, and they cease to produce insulin or do not produce enough.
When this occurs, blood glucose stays in the blood and cells cannot absorb them to convert the sugars into energy.
This is the onset of type 1 diabetes, and a person with this version of diabetes will need regular shots of insulin to survive.
In some people, especially those who are overweight, obese, or inactive, insulin is not effective in transporting glucose into the cells and unable to fulfill its actions. The inability of insulin to exert its effect on tissues is called insulin resistance.
Type 2 diabetes will develop when the islets cannot produce enough insulin to overcome insulin resistance.
Since the early 20th century, doctors have been able to isolate insulin and provide it in an injectable form to supplement the hormone for people who cannot produce it themselves or have increased insulin resistance.
Types of insulin
A person can take different types of insulin based on how long they need the effects of the supplementary hormone to last.
People categorize these types based on several different factors:
- speed of onset, or how quickly a person taking insulin can expect the effects to start.
- peak, or the speed at which the insulin reaches its greatest impact
- duration, or the time it takes for the insulin to wear off
- concentration, which in the United States is 100 units per milliliter (U100)
- the route of delivery, or whether the insulin requires injection under the skin,into a vein, or into the lungs by inhalation.
People most often deliver insulin into the subcutaneous tissue, or the fatty tissue located near the surface of the skin.
Three main groups of insulin are available.
The body absorbs this type into the bloodstream from the subcutaneous tissue extremely quickly.
People use fast-acting insulin to correct hyperglycemia, or high blood sugar, as well as control blood sugar spikes after eating.
This type includes:
- Rapid-acting insulin analogs: These take between 5 and 15 minutes to have an effect. However, the size of the dose impacts the duration of the effect. Assuming that rapid-acting insulin analogs last for 4 hours is a safe general rule.
- Regular human insulin: The onset of regular human insulin is between 30 minutes and an hour, and its effects on blood sugar last around 8 hours. A larger dose speeds up the onset but also delay the peak effect of regular human insulin.