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Diabetes: Types and Activity of Insulin

What is insulin?

Insulin is a hormone made in the pancreas, an organ inside the abdomen. Insulin is made by special cells called beta cells. Beta cells are in a part of the pancreas called the islets (pronounced eye-lets). When a person has type 1 diabetes, there is a loss of the beta cells which make insulin. Other cells in the pancreas and throughout the body continue to work normally.

What does insulin do?

Insulin helps our body turn the food we eat into energy. When we eat, our bodies convert the food into sugar. The sugar is carried through the blood. Throughout the day our blood sugar levels go up and down like a roller coaster. When we eat a meal, our blood sugar rises. After our meal, it drops back down again. Our bodies naturally produce the right amount of insulin to deal with the sugar level in our blood.

Insulin allows the sugar to pass from the blood into the cells. There it is burned for energy. The body cannot turn sugar into energy without insulin. Insulin also helps control how much sugar is made by "turning off" the making of sugar in the liver. If insulin is not available, sugar builds up in the blood and then starts to spill over into in the urine. People who have type 1 diabetes can't make enough insulin. These people need to take insulin through shots. Insulin cannot be taken as a pill, because the stomach acid destroys it. People who have type 2 diabetes still make insulin. They can take pills to help them make even more insulin or to be more sensitive to their own insulin.

To manage diabetes, your child needs the right kind of insulin at the right times during the day. The amount and kind of insulin you use is very important. If your child takes too much insulin or takes it at the wrong time, your child could have a serious low blood sugar reaction. If your child doesn't take enough insulin, the body will not be able to use the food for energy and the blood sugar will be too high.

What kind of insulin does my child need?

Most people with diabetes use human insulin. The human insulin does not come from humans, but has the same "make-up" as human insulin. It is produced by bacteria or by yeast using genetic engineering. There are no known advantages of one brand of insulin over another.

There are three major types of insulin:

  • rapid-acting
  • intermediate-acting
  • long-acting.

Most people use a combination of different types of insulin to match their eating schedule and lifestyle. After you inject insulin into the body, it takes some time for it to start working. The idea is to have the insulin working at its best when the blood sugar level is highest so the sugar can be absorbed and used by the body. Some kinds of insulin reach their peak activity very quickly. Others take awhile to reach their peak activity level. Below is a chart showing some types of insulin and when they have their peak effect.

                          Begins         Peak        All 
Name        Type          working       effect       gone 
Apidra      Rapid-acting   10-15 min.  30-90 min.     4 hrs.  

Regular     Rapid-acting   30-60 min.  2-4 hrs.     6-9 hrs.  

NPH         Intermediate 
              acting        1-2 hrs.    3-8 hrs.   12-15 hrs.  

Lantus      Long-acting     1-2 hrs.    2-22 hrs.     24 hrs.  

Humalog (or NovoLog or Apidra): These are clear, rapid-acting insulins that are usually taken right before meals. Because it works so fast, it can also be taken right after a meal. This is useful for people who are counting carbohydrates, for picky eaters, or for toddlers who do not always eat the same amount of food and can take their insulin right after they eat.

Regular: Regular insulin is also a clear, rapid-acting insulin, but takes longer to reach its peak than Humalog (or NovoLog or Apidra).

NPH: NPH is a cloudy, intermediate-acting insulin. NPH insulin is cloudy because it is made with a protein. This allows it to be absorbed by the body slower. If it is taken in the morning, the peak action comes in the afternoon. The peak in NPH insulin activity and how long it lasts may vary from person to person.

Lantus: Lantus is a clear insulin that lasts 24 hours with almost no peak. It is very consistent, unlike NPH, which can vary in peak activity even in the same person from one day to the next. If your child takes Lantus, he or she will still need to take rapid-acting insulin before meals.

How often is insulin given?

Depending on your child's condition, he or she will need to take 1 to 3 shots each day. Generally, the more shots your child takes, the better blood sugar control he or she can have.

One shot: A few people can have good blood sugar control by taking insulin once a day. This is often true during the "honeymoon" period that occurs shortly after treatment is started. Some children who take one injection a day take a combination of a rapid-acting and an intermediate-acting insulin. This puts insulin in your child's system during morning and afternoon. However, it will not last through the night and 2 shots per day are usually necessary.

Two shots: Most children have better sugar control using 2 or more shots of insulin per day. When your child has 2 shots per day, there are 3 (or more) small peaks of insulin activity. Each of the small peaks in insulin activity can be adjusted to fit your child's eating and activity schedule.

Three (or more) shots: Most people over age 12 take 3 (or more) shots of insulin each day. During the teen years, diabetes control may become more difficult. Teens usually need more insulin. The sex and growth hormones make it more difficult for insulin to work effectively.

How much insulin should my child take?

Your health care provider will help you figure out how much insulin to give your child. Insulin dosage is based on body weight, blood sugar test results, insulin sensitivity, exercise, and food. Your child's dose may not always stay the same. Some situations in which you will need to adjust the dosage include:

  • Honeymoon period: Many children have what is called a "honeymoon" or "grace" period a couple of weeks to months after first being treated for diabetes. During this time very little insulin is required. During this period it is important to check with your diabetes team frequently. The insulin dose needs to be adjusted to prevent low blood sugars.
  • Growth spurts: When going through a teenage growth spurt, the growth hormone level is high and blocks insulin activity. Your child will need more insulin until the growth spurt is over.
  • Activity level: If your child becomes more or less active, you will need to adjust the insulin dose. Exercise naturally lowers the blood sugar, so your child will need less insulin. For example, you may need to lower the insulin dose at dinner if your son or daughter has soccer practice or is going to play outside after dinner.
  • Food: Your child may need to adjust insulin dosage from time to time for special meals or if your child is counting carbohydrates.
Abstracted from the book, "Understanding Diabetes," 10th Edition, by H. Peter Chase, MD (available by calling 1-800-695-2873).
Published by McKesson Provider Technologies.
Last modified: 2005-12-09
Last reviewed: 2005-12-05
This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.
Copyright 2006 McKesson Corporation and/or one of its subsidiaries. All Rights Reserved.
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