What Is Type 1 Diabetes?

People who have type 1 diabetes can’t use glucose (the body’s main type of sugar) for energy. That’s because their body stopped making the hormone insulin. Normally, after we eat, the amount of glucose in the blood (blood sugar) goes up. When it does, the pancreas sends insulin into the blood. Insulin works like a key that opens the doors of the body’s cells to let the glucose in, giving the cells the energy they need.

In type 1 diabetes, the pancreas doesn’t make insulin. Without insulin, glucose can't get into the cells. It stays in the blood, which leads to high blood sugar. Having too much sugar in the blood isn’t healthy and can cause problems. Some problems happen quickly and need treatment right away, while others develop over time and show up later in life.

What Happens in Type 1 Diabetes?

In type 1 diabetes, the body's immune system attacks and destroys the cells in the pancreas that make insulin. So the body can’t make insulin anymore.

This is different from type 2 diabetes, where the body still makes insulin, but the insulin doesn’t work as it should.

Why Do Some People Get Type 1 Diabetes?

No one knows for sure why some people get type 1 diabetes. Doctors and scientists think a person’s genes make them more likely to get it. But just having the genes for diabetes probably isn't enough. It’s likely that something else needs to happen. Scientists are studying if other things — like some viral infections, a person’s birth weight, or their diet — might make someone who already has the genes for type 1 diabetes more likely to get it.

Type 1 diabetes can’t be prevented, and can happen in people of any age.

What Are the Signs & Symptoms of Type 1 Diabetes?

People can have diabetes without knowing it because the symptoms aren't always obvious and they can take a long time to develop. Type 1 diabetes may come on gradually or suddenly.

When a person first has type 1 diabetes, they may:

pee a lot because the body tries to get rid of the extra blood sugar by passing it out of the body in the urine
drink a lot to make up for all that peeing
eat a lot because the body is hungry for the energy it can't get from sugar
lose weight because the body starts to use fat and muscle for fuel
feel tired a lot

If these early symptoms of diabetes aren't recognized and treatment isn't started, chemicals can build up in the blood and cause stomach pain, nausea, vomiting, breathing problems, and even loss of consciousness. Doctors call this diabetic ketoacidosis, or DKA.

There's good news, though — getting treatment can control or stop these diabetes symptoms from happening and reduce the risk of long-term problems.

How Is Type 1 Diabetes Diagnosed?

Doctors use a blood test that measures the amount of sugar (glucose) in the blood. High blood sugars show that a person has diabetes. Then, the doctor will do more blood tests to find out what type it is.

Teens with type 1 diabetes often go to a pediatric endocrinologist. This is a doctor who specializes in diagnosing and treating kids and teens living with diseases of the endocrine system, such as diabetes and growth problems.

How Is Type 1 Diabetes Treated?

People with type 1 diabetes have to pay a little more attention to what they eat and do than people who don't have diabetes.

They need to:

check blood sugar levels as prescribed
give themselves insulin injections or use an insulin pump as prescribed
eat a healthy, balanced diet with accurate carbohydrate counts
get regular exercise
have regular checkups with doctors and other people on their diabetes health care team so they can stay healthy and get treatment for any diabetes problems

What Can Help Me Manage Type 1 Diabetes?

Sometimes people who have diabetes feel different from their friends because they need to take insulin, think about how they eat, and control their blood sugar levels every day. They may feel angry or depressed, or think that their parents are constantly worrying about their diabetes management.

Diabetes brings challenges, but people who have it play sports, travel, date, go to school, and work just like their friends.

Managing your diabetes might feel overwhelming at times, but you're not alone. Reach out to your diabetes health care team. They can answer questions and help with all kinds of issues. Don't hesitate to ask your doctors, dietitian, and others on the team for advice and tips. You might want to find a support group where you can talk about your feelings and find out how other people cope.

You also can get more information and support online at:

Reviewed by: Cheryl Patterson, RD, LDN, CDCES
Date Reviewed: Sep 23, 2021