What Is Type 1 Diabetes?

Type 1 diabetes is an autoimmune condition in which the body mistakenly attacks the insulin-producing cells in the pancreas. This leads to little to no insulin in the body and causes high blood sugar levels.

There’s no cure for the condition. If left unmanaged, type 1 diabetes can lead to serious health complications, such as amputation or vision loss, so caring for yourself is vital with this condition. 

This article covers everything someone newly diagnosed with type 1 diabetes needs to know, from symptoms and causes to treatment and lifestyle changes. 

Insulin helps transport glucose from the bloodstream with the help of glucose transporters.

What Does Type 1 Diabetes Do to the Body?

Insulin is a hormone made in the pancreas by cells called beta cells. Insulin helps glucose (sugar) in the bloodstream to leave the blood and enter cells to be used for energy or be stored for later use. Glucose is used to fuel many functions in the body, including physical and mental functions. 

In type 1 diabetes, the body mistakenly attacks its own healthy tissue (an autoimmune reaction), in this case by destroying the insulin-producing beta cells. This process may happen for months or years prior to symptoms occurring.

Over time, less and less insulin is produced. This leads to less glucose being available to enter the cells in your body to be used for energy, causing high blood glucose levels

If not treated, high blood glucose levels can lead to serious health complications, including oral health problems, kidney disease, vision loss, and amputation of extremities.

Is Type 1 Diabetes Genetic?

Type 1 diabetes seems to have a genetic component. Having a parent or sibling with type 1 diabetes increases your risk of developing the condition.

Most people who develop type 1 diabetes have inherited certain genes from both parents. Therefore, having certain genes from both parents increases the risk of developing type 1 diabetes.

However, not all people who are at risk will go on to develop type 1 diabetes. A trigger in the environment might initiate the autoimmune response that leads to type 1 diabetes. 

In the United States, non-Hispanic White adults have the highest rate of type 1 diabetes. Because of this, experts suspect these genes are more common in White people.

What Causes Type 1 Diabetes?

Experts are not sure of the exact cause of type 1 diabetes. However, it’s thought to be caused by an autoimmune reaction. This autoimmune reaction may occur due to one or more environmental triggers, such as a virus or the foods in your diet.

One of the biggest known risk factors for type 1 diabetes is having a parent or sibling with type 1 diabetes. While you can develop type 1 diabetes at any age, it is more commonly diagnosed in children, adolescents, and young adults.

Type 1 Diabetes Symptoms

Type 1 diabetes symptoms tend to come on suddenly. They include:

Symptoms of Type 1 Diabetes in Children

In addition to the above symptoms, children may have other symptoms of type 1 diabetes. These include:

  • More restless or irritable than usual
  • Lethargy (fatigue or lack of energy)
  • Heavy or labored breathing
  • Nausea and vomiting
  • New night time bed-wetting
  • Fruity smelling breath

What Is Diabetic Ketoacidosis?

Diabetic ketoacidosis (DKA) is a serious complication of diabetes. It is more common in people with type 1 diabetes compared to people with type 2 diabetes. DKA develops when your body doesn’t have enough insulin to move blood glucose into cells to be used as fuel for the body, leading to very high blood glucose levels. 

Glucose is the body’s preferred energy source. When there is no glucose readily available, the body turns to breaking down fat as its source of energy. In this process of breaking down fat, acids called ketones are produced. 

When too many ketones build up too fast in the body, it can be life-threatening.

Signs and symptoms of DKA include:

  • Extreme thirst
  • Frequent urination
  • Extreme fatigue
  • Fast, labored breathing
  • Dry skin and mouth
  • Flushed face
  • Fruity-smelling breath
  • Headache
  • Muscle stiffness or aches
  • Nausea and vomiting
  • Stomach pain

Seek medical attention immediately if you or someone you know is experiencing DKA or has high ketones in their urine.

Type 1 vs. Type 2 Diabetes: What’s the Difference?

While high blood glucose levels characterize both type 1 and type 2 diabetes, these conditions do not have the same causes and may have very different treatment plans. 

The signs and symptoms of diabetes are similar in both type 1 and type 2. However, type 1 diabetes symptoms tend to come on suddenly, while type 2 diabetes symptoms tend to appear more gradually. Some people with type 2 diabetes may not notice symptoms at all.

Type 2 diabetes is most commonly diagnosed in people aged 45 years or older, whereas type 1 diabetes is more frequently diagnosed in children, teens, and young adults. Because of this, type 1 diabetes was previously referred to as juvenile diabetes.

Type 2 diabetes is not an autoimmune condition. Instead, it is a chronic medical condition that occurs due to multiple factors, including certain lifestyle habits and genetics.

Insulin resistance (when your cells don’t respond properly to insulin) is typically seen in people with type 2 diabetes. Insulin resistance is often the main cause of high blood glucose levels in people with type 2 diabetes.

Type 2 diabetes may be able to be prevented or delayed. On the other hand, type 1 diabetes cannot be prevented or cured.

Because their body no longer makes insulin, people with type 1 diabetes require insulin (via injection, pump, or inhalation) as part of their daily diabetes management.

Treatment for people with type 2 diabetes includes healthy lifestyle habits, such as a balanced diet, regular physical activity, and getting to and maintaining a healthy weight. It may also include oral or injectable medications.

People with type 1 diabetes need to monitor their blood glucose levels frequently throughout the day, while people with type 2 diabetes may not have to check their blood glucose levels as often.

Testing for Type 1 Diabetes

Diabetes is diagnosed using a blood test that checks your blood glucose levels. A healthcare provider may perform the following tests, which indicate diabetes at the levels cited:

  • Random blood glucose test: 200 milligrams per deciliter (mg/dL) or higher with symptoms of diabetes
  • Fasting blood glucose test (FBG): 126 mg/dL or higher
  • Hemoglobin A1C test: 6.5% or higher
  • Oral glucose tolerance test (OGTT): 200 mg/dL two hours after drinking a liquid containing glucose

If your healthcare provider suspects you have type 1 diabetes, they may also check your blood for certain autoantibodies. Autoantibody presence indicates antibodies are destroying the beta cells in your body.

If your blood glucose levels are very high, your healthcare provider may also check your urine for the presence of ketones.

Type 1 Diabetes Treatment

The main treatment for type 1 diabetes is insulin. External insulin is necessary to survive because the body can no longer make insulin. Insulin is administered via needle and syringe, insulin pen, inhaler, or insulin pump.

To determine how much insulin the body needs, it’s important to check blood glucose levels frequently throughout the day, such as before and after eating and before going to bed. 

This is traditionally done by a small finger prick to test a tiny amount of blood using a glucose meter (glucometer). However, more and more people with type 1 diabetes use continuous glucose monitors (CGMs). A CGM is a small, wearable device that automatically and frequently checks blood glucose levels 24/7.

To eliminate the need for multiple daily insulin injections, many people with type 1 diabetes use insulin infusion pumps. Insulin pumps are small, wearable devices that deliver insulin to the body through a thin, plastic tube (catheter) and a small needle inserted into the fatty tissue under the skin.

With advancements in technology, more and more people with type 1 diabetes are managing their diabetes with automated insulin delivery systems (AIDS), also called an artificial pancreas. An AIDS is a computer algorithm program that connects CGMs and insulin pumps, allowing them to work together to act as a healthy pancreas would for insulin and blood glucose management.

In addition to insulin, other medications may be recommended to help manage your type 1 diabetes.

Managing Diabetes with Lifestyle Changes

Engaging in healthy lifestyle habits is important for everyone, including people with type 1 diabetes.

There is no one specific “diabetes diet,” People with type 1 diabetes are encouraged to follow a healthy, balanced eating pattern that includes vegetables, fruit, whole grains, lean protein, low-fat dairy, and heart-healthy fats.

Engaging in regular physical activity is another important aspect of a healthy lifestyle. Both aerobic exercise and strength training should be included as part of a physical activity routine. 

In general, it’s recommended that adults get 150 minutes of moderate-intensity aerobic activity each week, along with at least two days of strength training each week.

Stress can affect blood glucose levels. In addition, living with type 1 diabetes can take a toll on mental health.

Finding ways to effectively manage stress and cope with the never-ending to-do list of living with type 1 diabetes is important for both mental and physical health. Ideas include going for a walk, talking with a friend or loved one, writing in a journal, meditating, or reading a good book.

You may also want to look for a diabetes support group, locally or through the Diabetes Online Community. A study of adults with type 1 diabetes who engaged with the Diabetes Online Community found they reported improved physical and mental health from seeking information and support online.

Common Complications of Diabetes

If diabetes is left unmanaged, over time it can lead to serious health complications. These include:

Type 1 Diabetes Life Expectancy

Prior to the discovery of insulin therapy for type 1 diabetes, a diagnosis of type 1 diabetes was a death sentence, with more than 90% of people dying within five years of diagnosis.

However, this is no longer the case. People with type 1 diabetes can now live long and fulfilling lives with proper care and management.  

Still, regardless of the advancements in diabetes care, people with type 1 diabetes still have shorter expected life spans than the general population. The average life expectancy for all people in the United States is 76.1 years.

According to a Scottish study, people with type 1 diabetes at the age of 20 lived an average of 12 fewer years than 20-year-olds without it. An Australian study produced similar results, finding that people with type 1 diabetes lived 12.2 fewer years compared with the general population.

Managing your diabetes and keeping blood glucose levels in target range can help you live a longer life with diabetes. According to a 2015 study, people with type 1 diabetes with better blood glucose control lived longer than those with poorer blood glucose control.


Type 1 diabetes is an autoimmune condition in which the body mistakenly attacks cells in the pancreas that produce insulin. The exact cause is unknown, though it’s thought to be brought on by a combination of genetics and environmental triggers.

The condition is characterized by high blood glucose levels, which can lead to serious health complications, such as eye disease, kidney disease, nerve damage, and foot problems. Common signs and symptoms of diabetes include frequent urination, increased thirst and hunger, blurry vision, unintentional weight loss, and fatigue.

Diabetes is diagnosed using a blood test to check blood glucose levels. Type 1 diabetes and type 2 diabetes vary in that they are typically diagnosed at different life stages, and have different causes, symptom onset, and treatment.

Type 1 diabetes is mainly treated by frequent blood glucose monitoring and administering insulin via needle and syringe, insulin pen, insulin pump, or inhaler. To make living with diabetes easier, many people with type 1 diabetes use a continuous glucose monitor, insulin pump, or automated insulin delivery system.

In addition to insulin therapy, lifestyle habits, including a healthy diet and regular physical activity, can help in managing blood glucose levels. Though life expectancy has increased over the years for people with type 1 diabetes, it is still shorter than the general population by about 12 years.

24 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Brittany Poulson, MDA, RDN, CDCES

By Brittany Poulson, MDA, RDN, CD, CDCES
Poulson is a registered dietician and certified diabetes care and education specialist. She is based in Utah.