Insulin is produced by special cells in
the pancreas, a large organ
located behind the stomach. Insulin helps the body use or store
glucose (sugar), which is produced during the digestion of food. Insulin is
secreted into the blood at each meal and allows the body to use glucose as
energy to fuel basic daily functions like moving and breathing. Insulin also
enables the body to store extra glucose as fat. The May 7, 2003, issue of
JAMA includes 2 articles about insulin therapy for patients with
If there is not enough insulin or if the body cannot use the insulin
produced, individuals develop a condition known as diabetes. Blood
glucose levels can become high. If the body is unable to use glucose,
it starts breaking down fats for energy. This produces waste products
called ketones. High levels of ketones cause a dangerous condition
called ketoacidocis that requires immediate medical attention. On the
other hand, too much insulin can cause hypoglycemia (low blood sugar).
There are two major types of diabetes. In type 1 diabetes, the pancreas does not produce enough insulin. People
with type 2 diabetes have what is
called insulin resistance and eventually cannot
make enough insulin to meet their needs. They may start treatment by losing
weight with diet and exercise or by taking pills, or they may need
insulin right away.
Insulin must be delivered to the bloodstream and is usually given by
injection. Doctors or nurses teach patients how to inject insulin.
Many individuals with diabetes inject insulin under the skin of the
belly; others prefer the arm or thigh. Some patients with type 1 diabetes
use an insulin "pump" that delivers insulin through a tiny tube placed
under the skin.
Individuals with diabetes who need insulin must take it every day. They
need insulin all the time to move glucose from the blood into the muscles
where it is used, and they need enough insulin to absorb the glucose from
food. The dose of insulin for meals depends on the amount of carbohydrates
consumed. Blood glucose levels must be measured throughout the day by taking
a small drop of blood (usually by a pinprick to the finger) and placing it
in a meter that measures the blood glucose level.
There are several types of insulin that differ based on how long it takes
the insulin to start working after it is injected (onset), when the
insulin, is working hardest (peak), and how long the insulin lasts in the
body (duration). Some individuals with diabetes use different types of
insulin in various proportions and combinations depending on the time of
day and timing of meals. Your doctor can help you determine the insulin
types and schedule that are best for your needs.
American Diabetes Association800/DIABETEShttp://www.diabetes.org
National Diabetes Information Clearinghouse800/860-8747http://www.niddk.nih.gov/health/diabetes/pubs/dcct/ndiclink.htm
To find this and previous JAMA Patient Pages, go to the Patient
Page Index on JAMA's Web site
at http://www.jama.com. A Patient Page on diabetes was published in
the September 26, 2001, issue, and one on diabetes management was
published in the January 12, 2000, issue.
The JAMA Patient Page is a public service
of JAMA. The information and
recommendations appearing on this page
are appropriate in most instances, but they are not a substitute for
medical diagnosis. For specific information concerning your personal
medical condition, JAMA suggests that you
consult your physician. This page may be photocopied noncommercially by
physicians and other health care professionals to share with patients.
Any other print or online reproduction is subject to AMA approval. To
purchase bulk reprints, call 718/946-7424.
Sources: American Diabetes Association, National Institute of
Diabetes & Digestive & Kidney Diseases, American Association of
Parmet S, Lynm C, Glass RM. Insulin. JAMA. 2003;289(17):2314. doi:10.1001/jama.289.17.2314