On this page you will learn about:
Normal or non-diabetic blood glucose levels and insulin release from the pancreas
Natural insulin (i.e. insulin released from your pancreas) keeps your blood glucose in a very narrow range. Overnight and between meals, the normal, non-diabetic blood glucose ranges between 60-100 mg/dl and 140 mg/dl or less after meals and snacks. See the picture below of blood glucose levels throughout the day in someone who does not have diabetes.
To keep the blood glucose managed overnight, fasting and between meals, your body releases a low, background level of insulin. When you eat, there is a large burst of insulin. This surge of insulin is needed to dispose of all the carbohydrate or sugar that is getting absorbed from your meal. All of this happens automatically!
More about natural insulin release
Insulin is continuously released from the pancreas into the bloodstream. Although the insulin is quickly destroyed (5-6 minutes) the effect on cells may last 1-1/2 hours. When your body needs more insulin, the blood levels quickly rise, and, the converse – when you need less, the blood levels rapidly fall —The situation is different when you have diabetes and are getting insulin replacement therapy. Once you have injected a dose of insulin, it is going to get absorbed into your bloodstream whether you need it or not.
At mealtime, a little insulin is released even as you are first smelling or chewing the food. This gets your body ready to receive the glucose load from the meal. Then as you eat and the food is digested, the sugar levels rise which causes a surge of insulin. The insulin levels rapidly climb and peak in about 45 minutes to 1 hour before falling back to the background or basal levels –The situation is different when you have diabetes and are getting insulin replacement therapy. You have to calculate how much carbohydrate you are going to eat and how much insulin you will need. And you have to try to mimic natural overnight, fasting (or between meals) and mealtime insulin release with injected insulin. See the picture below illustrating overnight, fasting and between meals insulin, and the large spikes of insulin that accompany meals.
Principles of insulin replacement
When you have type 2 diabetes and don’t have enough of your own insulin, or cannot take other medications to control your blood glucose, you will need to start insulin therapy. The insulin therapy tries to mimic natural or non-diabetic insulin secretion. There are two components of insulin therapy:1. Background or basal insulin replacement
- Controls glucose overnight and between meals by keeping fat in fat tissue and curbing glucose production from the liver.
- Provides a low, continuous level of insulin.
- Can be a long-acting insulin, which you inject once or twice daily such as the insulin analogs, insulin glargine, insulin degludec, insulin detemir and NPH.
- Or can be a rapid-acting insulin continuously infused under the skin, if you are using an insulin pump.
- Represents about 50% or half of the body's daily insulin requirements.
2. Bolus insulin replacement
Two kinds of bolus replacement
- Mealtime Bolus – to cover the carbohydrate in the meal or snack.
- High Blood Glucose Correction Bolus – provides extra insulin to return the blood glucose back to the target level when your blood glucose is too high.
- Bolus Insulin is usually provided by rapid-acting insulin analogs, such as insulin aspart, insulin lispro, and insulin glulisine or Regular insulin.
- Represents about 10% to 20% of the daily insulin requirement at each meal, or about 50% of the body's daily insulin needs.
- Types and characteristics of insulin medications
- Insulin administration
- Designing an insulin regimen
- Calculating your insulin dose
- Intensive insulin therapy
- Sliding scale insulin therapy
- Insulin pump therapy
