Diabetes: Basic Facts

What is diabetes?

Diabetes is a disease that affects the way the body turns sugar into energy. There are several types of diabetes.

How the Body Turns Sugar into Energy

The food we eat is made up of three things. They are carbohydrates (CAR-bow-HIdrates), which are sugars and starches; protein (PRO-teen); and fat. When we eat, a healthy body changes all of the carbohydrates and some of the protein and fat into a sugar. This sugar is called glucose (GLOOcose). From the small intestine, glucose moves into the blood. From the blood, glucose then moves into the cells of the body. The sugar we call glucose is the fuel, or energy, that the cells of the body need to do their work.

Near the stomach is an organ called the pancreas (PAN-kree-us). The pancreas makes insulin (IN-suh-lin). Insulin is a hormone. When we eat, the sugar level in the blood goes up. The pancreas puts out more insulin. The insulin helps move the sugar out of the blood into the cells. The cells use the sugar for energy or store the sugar for use later.

What happens when you have diabetes?

When you have diabetes, your body either doesn’t make enough insulin or doesn’t use the insulin properly. Sugar stays in your blood. Then the cells don’t get enough sugar for fuel. The body doesn’t have enough energy to do its work. Over time, the high level of sugar in the blood can damage the body.

What are the types of diabetes?

Three types of diabetes are the most common.

Type 1 diabetes

In Type 1 diabetes, the pancreas does not make insulin. Sugar is unable to get into the cells. So the sugar level in the blood goes up. When the sugar level rises above normal, a person has high blood glucose. The name for high blood glucose is hyperglycemia (HIper-glice-EE-mee-uh). Most often children  and young adults get Type 1 diabetes.

Type 2 diabetes

In Type 2 diabetes, the pancreas still makes insulin. But the insulin doesn’t work right, or the cells can’t take in the sugar. The sugar level in the blood goes up. A person then has high blood glucose, or hyperglycemia.

People who tend to get Type 2 diabetes are:

  • People who are overweight
  • African Americans, Hispanics, Asians, Pacific Islanders, or Native Americans
  • People with a history of diabetes in their family
  • Women who have had a baby weighing over 9 pounds at birth

Diabetes during pregnancy

Women who are pregnant may get gestational (jess-TAY-shun-ul) diabetes. Because of the hormone changes in pregnancy, sometimes the pancreas does not make enough insulin. After pregnancy, gestational diabetes often goes away. Some women with gestational diabetes may get diabetes in the future. If you had gestational diabetes in the past, you should have your blood glucose checked often. See the UPMC patient education sheet Diabetes and Pregnancy for more information.

Secondary diabetes (diabetes caused by other health problems)

High blood glucose levels can occur from treatments for other diseases. When this happens, it is called secondary diabetes. This means that diabetes was not the primary or first problem. Secondary diabetes can happen when blood glucoses rise because of certain medications, like some chemotherapy drugs or steroids. Some anti-rejection drugs that are used following organ transplantation can also affect blood glucoses. Secondary diabetes is usually treated with insulin, a sound nutrition plan, and monitoring.

Secondary diabetes is often a temporary problem. Once you reduce or stop taking the medications, like steroids or anti-rejection drugs, your blood glucose may go back to normal. If, however, the drugs are started again, you should be careful to check your blood glucose levels regularly again.

What are the symptoms of diabetes?

Symptoms of diabetes include:

  • Extreme tiredness
  • Increased thirst
  • Weight loss
  • Blurry vision
  • Passing water (urinating) often
  • Cuts or sores that don’t heal well

A person with Type 2 diabetes may have some of these symptoms. A person may not have any symptoms at all and have Type 2 diabetes.

How do you know if you have diabetes?

Blood glucose tests are the main way to learn if you have diabetes. The tests measure the number of milligrams (mg) of glucose in a deciliter (dl) of blood. After a person has fasted, the normal glucose level is 70 to 99 mg/dl (milligrams in a deciliter) of blood. After a person eats, normally blood glucose may go higher, but rarely over 200. The American Diabetes Association lists the following ways to tell if a person has diabetes:

  • A person has symptoms of diabetes and a high blood glucose level (200 or higher) on a blood glucose test.
  • A person has a fasting blood glucose level of 126 or higher. For a fasting blood glucose test, the person does not eat or drink for at least 8 hours before blood is taken.
  • A person has a blood glucose level of 200 or higher after drinking a special sugar solution. This test is called an oral glucose tolerance test.
  • A person has an A1c (A-oneC) level of 6.5% or higher (this test shows the estimated average blood glucose level over the past 2-3 months).

Your doctor may repeat a test to confirm a diagnosis of diabetes unless diabetes is clear based on other signs and symptoms.

If You Have Diabetes

If you have diabetes, you should try to get and keep your blood glucose level as close to normal as possible. It’s good to have a blood glucose level between 70 to 130 during the day before eating. At bedtime, the goal is to have blood glucose at 110 to 150. The goal for A1c is less than 7%. Ask your doctor what your personal goals should be. For more information about managing your diabetes, see the UPMC patient education sheet Diabetes: Your Management Plan.

If You are at Risk for Diabetes

Sometimes a person has blood glucose higher than normal, but not high enough to have diabetes. This condition is called impaired fasting glucose or impaired glucose tolerance. The person does not yet have diabetes, but is at risk for getting diabetes. This is sometimes called prediabetes. If you have this condition, ask your doctor what to do about your blood glucose. See the UPMC patient education sheet Pre-Diabetes.

Some useful resources include:

  • UPMC To find a doctor or a diabetes class, call: 1-800-533-UPMC (8762)
  • University of Pittsburgh Diabetes Institute
    UPMC Diabetes Centers
  • American Diabetes Association (ADA)
    1-800-DIABETES (342-2383)
  • American Association of Diabetes Educators
    1-800-TEAMUP4 (832-6874)
  • Juvenile Diabetes Foundation International (JDF)
    1-800-JDF-CURE (533-2873)
  • American Dietetic Association National Center for Nutrition and Dietetics Hotline

Revised July 2013​

UPMC | Affiliated with the University of Pittsburgh Schools of the Health Sciences | Supplemental content provided by Healthwise, Incorporated. To learn more, visit www.healthwise.org

For help in finding a doctor or health service that suits your needs, call the UPMC Referral Service at 412-647-UPMC (8762) or 1-800-533-UPMC (8762). Select option 1.

UPMC is an equal opportunity employer. UPMC policy prohibits discrimination or harassment on the basis of race, color, religion, ancestry, national origin, age, sex, genetics, sexual orientation, gender identity, marital status, familial status, disability, veteran status, or any other legally protected group status. Further, UPMC will continue to support and promote equal employment opportunity, human dignity, and racial, ethnic, and cultural diversity. This policy applies to admissions, employment, and access to and treatment in UPMC programs and activities. This commitment is made by UPMC in accordance with federal, state, and/or local laws and regulations.

Medical information made available on UPMC.com is not intended to be used as a substitute for professional medical advice, diagnosis, or treatment. You should not rely entirely on this information for your health care needs. Ask your own doctor or health care provider any specific medical questions that you have. Further, UPMC.com is not a tool to be used in the case of an emergency. If an emergency arises, you should seek appropriate emergency medical services.

Pittsburgh, PA, USA | UPMC.com