If you have been diagnosed with diabetes mellitus, your doctor may recommend insulin as part of your treatment. Learning about insulin therapy will help you understand its importance in managing your diabetes. Knowing how insulin therapy works will also help you work with your doctor to select the treatment plan that best suits you.
What is insulin?
Insulin is one of the many hormones produced by your body. Hormones are proteins that help your body’s cells in carrying out many different processes. Insulin, in particular, is one of the hormones in charge of keeping your blood glucose (or sugar) at a normal level. Glucose is a carbohydrate that comes from the food that you eat. It may also be made by your liver. The cells in your body, especially those in your brain and muscles, use glucose as their main fuel.
Insulin allows your cells to take glucose from your blood. The beta cells in your pancreas are responsible for releasing insulin into your bloodstream. Normally, if there is a high level of glucose in your blood, more insulin is released. This lets your cells take up more glucose, bringing down your blood glucose level back to normal. If there is a low amount of glucose available in your blood, less insulin is released. In a healthy person, the body adjusts the amount of insulin released in order to make sure that the blood glucose level is neither too high nor too low.
Why do I need insulin therapy?
When you have diabetes, the insulin in your body is not enough to control your blood glucose level. If you have type 1 diabetes, this means that the beta cells in your pancreas have been destroyed. Your body can no longer make its own insulin. You will need insulin therapy to provide the insulin that your body lacks.
If you have type 2 diabetes, your body still produces its own insulin. However, your cells are not able to use the insulin to take up glucose from your blood. This is known as insulin resistance.
At first, your doctor may recommend medicines (called oral hypoglycemic agents, or OHAs) that can help lower your blood glucose level. OHAs, together with a balanced diet and an exercise plan, are used to manage type 2 diabetes. Over time, however, you may need insulin therapy in addition to OHAs to make sure your blood glucose level is well controlled.
How do I take insulin?
Insulin is injected into your body, usually in a place where there is some fat. The fat absorbs the insulin, allowing the insulin to then enter your bloodstream. The best site for insulin injection is your abdomen. Other sites that can be used for insulin injection are your upper arms, thighs, and buttocks.
Insulin therapy is designed to closely match the way a healthy body normally releases insulin. Typically, your pancreas secretes a constant amount of insulin 24 hours a day. This basal level of insulin ensures that your cells can take up glucose from your bloodstream any time they need it. It also controls your blood glucose level throughout the day.
After you eat, a larger amount of insulin is released. This is because when food is digested, your blood glucose level goes up. Thus, more insulin is needed for your cells to take up glucose and keep your blood glucose at an appropriate level. However, once glucose from your meal is taken up, your insulin again goes down to the basal level.
To recreate the way a healthy body secretes insulin, insulin therapy makes use of different kinds of insulin preparations. These types of insulin differ in the following ways:
- Onset of action, or how quickly they start to work
- Peak time, which is the time when the insulin is most effective
- Duration, which refers to the length of time the insulin is able to work in lowering your blood glucose level.
The types of insulin used in insulin therapy are:
- Long -acting insulin, which has an onset of 6 to 10 hours after injection and a duration of 20 to 24 hours. It is meant to mimic the way the pancreas releases insulin constantly throughout the day. Since long-acting insulin is meant to act like basal insulin, it does not have as much of a peak of action as other types of insulin.
- Intermediate-acting insulin, which has an onset of 2 to 4 hours after injection and lasts 12 to 18 hours. Its peak time is about 4 to 12 hours after injection.
- Regular or short-acting insulin, which starts working 30 minutes after injection. It then peaks two to three hours later. Short-acting insulin lasts for 3 to 6 hours. These characteristics make short-acting insulin ideal for injection before mealtime.
- Rapid-acting insulin is meant to lower your blood glucose after eating. Its onset of action begins 5 minutes after injection. Rapid-acting insulin peaks in one hour. It continues to be effective for two to four hours.
Your doctor may combine these different types of insulin in order to keep your blood glucose level within normal range. You will be given insulin that acts like basal insulin. You will also get extra insulin that is needed to lower your blood glucose levels after a meal. The amount and kind of insulin that will be used in your therapy depend on your diet, physical activity, and your general lifestyle. You and your doctor will work together to come up with an insulin therapy plan that will keep your blood glucose well controlled.