What is diabetes?

Diabetes is a disease of metabolism, which is the way your body uses food for energy and growth.¹ In particular, it’s related to one of the food nutrients that supply energy, called carbohydrates.² Normally, your stomach and intestines digest the carbohydrates in your food into a sugar called glucose. Glucose is your body’s main source of energy. After digestion, the glucose moves into your blood to give your body energy.

To get the glucose out of your blood and into the cells of your body, your pancreas makes a hormone called insulin. If you have diabetes, either your body doesn’t make enough insulin, or your cells can’t use it the way they should. Instead, the glucose builds up in your blood, causing diabetes, otherwise known as high blood sugar.

Diabetes is generally divided into three categories:

• Type 1—Also known as juvenile diabetes, type 1 diabetes is a condition in which the pancreas does not make enough insulin.³
• Type 2—This develops when the body becomes resistant insulin, and as a result the pancreas can no longer make enough insulin to keep blood sugar levels in balance.³ It used to be known as adult-onset diabetes, because it was seen mainly in adults, especially older ones (age 40 and up)⁴. Today, many obese children are developing type 2 diabetes.
• Gestational diabetes—Also known as gestational diabetes mellitus, this is a type of diabetes that only occurs in pregnant women. If a pregnant woman develops diabetes, but she didn’t have it before becoming pregnant, then she has gestational diabetes.

One of the key dangers of diabetes is that it often doesn’t display any symptoms at all, making it hard to diagnose until it’s severe.

Common symptoms generally include:¹

• Unusual thirst
• Fatigue
• Frequent urination
• Extreme hunger
• Irritability, mood changes

Other symptoms that can occur:

• Cuts that are difficult or slow to heal
• Tingling/numbness in hands and/or feet
• Blurred vision
• Frequent infections

For pregnant women, swelling in the hands and face and may also be symptoms of gestational diabetes.

Diabetes is a disease of metabolism, which is the way the body uses food for energy and growth.¹ In particular, it’s related to one of the food nutrients that supply energy, called carbohydrates.² Normally, the stomach and intestines digest the carbohydrates in food into a sugar called glucose. Glucose is the body’s main source of energy. After digestion, the glucose moves into the blood to give the body energy.

To get the glucose out of blood and into the body’s cells, the pancreas makes a hormone called insulin. In diabetes, either the body doesn’t make enough insulin, or the cells can’t use it the way they should. Instead, the glucose builds up in the blood, causing diabetes, otherwise known as high blood sugar.

The exact causes of diabetes are not fully understood and typically involve multiple factors, such as genetics and interactions with the environment.

The majority of cases of type 1 diabetes are “sporadic” meaning there is no family history of the condition. Likewise, the rates of type 1 diabetes in both members of set of identical twins is lower than would be expected if the condition was caused by genetics alone. The environmental component is strong and could result from a combination of factors, such as exposure to viruses in the small intestine or to foreign proteins from foods at a time when the immune system of the digestive tract is too immature to process them.

Researchers leading the Trial to Reduce the Incidence of Type 1 Diabetes Mellitus in the Genetically at Risk (TRIGR), which is supported in part by the NICHD, are examining whether exposure to foreign proteins from cow’s milk or cow milk-based infant formula can cause type 1 diabetes, especially in children who are at high risk for the condition based on their family history and genetic profile. The Trial aims to determine whether a nutritional intervention—feeding cow milk-based formulas that have been specially processed to remove the foreign proteins—during infancy can delay or prevent the onset of type 1 diabetes in children at high risk for the condition.

Obesity is a major factor in developing type 2 diabetes. Most Americans with type 2 diabetes are obese or overweight. Obesity reduces the body’s ability to control blood sugar, so the body overproduces insulin to compensate—and a cycle develops.³

Pregnancy causes many different changes to the body, including changes to metabolism that result in gestational diabetes. These changes are usually the result of hormones produced during pregnancy that keep insulin from doing its job.

The most common test for diagnosing any kind of diabetes is a one-step approach called the oral glucose tolerance test. Prior to the test, you can’t eat or drink anything (except water) for between 4 and 8 hours. A health provider tests your initial sugar level and then gives you a sugar drink. Then your sugar level is checked every 30 to 60 minutes for up to 3 hours.^1,2

Although the NICHD studies different aspects of all types of diabetes, the NICHD is not the primary resource for patient information about type 1 or type 2 diabetes. The National Diabetes Information Clearinghouse and the National Diabetes Education Program provide detailed information about type 1 and type 2 diabetes, including specific information about diagnosis and glucose levels.

Risk for type 1 diabetes

Health care providers can use a test to check for certain blood markers that can predict how likely it is that someone will develop type 1 diabetes. These blood markers signal that the immune system is attacking the beta cells of the pancreas. Having two or more of these markers, called antibodies, is associated with higher risk of developing type 1 diabetes over the next 10 years.³

Testing for gestational diabetes

Health care providers will consider a woman’s risk factors and current health before testing for gestational diabetes. If a woman is at high risk for gestational diabetes, her health care provider will test her as soon as she knows she is pregnant. If a woman is at low risk for gestational diabetes, her health care provider might not test her at all, or will test her between 24 weeks and 28 weeks of pregnancy. For more information about testing for gestational diabetes, see the NICHD’s Am I at risk for gestational diabetes? brochure.

There are two main types of treatment for diabetes:

• Lifestyle changes—These include changing your diet to something healthier and improving your exercise/activity level. More information on lifestyle changes to control diabetes can be found at the National Diabetes Education Program.
• Medication—Oral medicines and sometimes injections with insulin may be used. For more information on medications to control diabetes, visit the National Diabetes Information Clearinghouse.