Top of the page
This topic covers type 1 diabetes, including information about symptoms, tests, and home treatment. For specific information about children who have type 1 diabetes, see the topic Type 1 Diabetes: Children Living With the Disease.
Type 1 diabetes happens when your pancreas stops making insulin.
Insulin is a hormone that helps the body's cells use sugar (glucose) for energy. It also helps the body store extra energy in muscle, fat, and liver cells. Without insulin, this sugar can't get into your cells to do its work. It stays in your blood instead. And then your blood sugar level gets too high.
High blood sugar can harm many parts of the body, such as the eyes, heart, blood vessels, nerves, and kidneys. It can also increase your risk for other health problems (complications).
Type 1 diabetes can occur at any age, but it usually starts in children or young adults. That's why it used to be called juvenile diabetes.
Type 1 diabetes is different from type 2 diabetes. In type 1 diabetes, the body stops making insulin. In type 2, the body can't use insulin the right way. Over time with type 2, the body doesn't make enough insulin.
There isn't a cure for type 1 diabetes. But with treatment, people can live long and healthy lives.
The body makes insulin in beta cells, which are in a part of the pancreas called the islet (say "EYE-let") tissue. Type 1 diabetes starts because the body destroys those beta cells. Experts don't know why this happens.
Some people have a greater chance of getting type 1 diabetes because they have a parent, brother, or sister who has it. But most people with the illness don't have a family history.
Other things that increase the risk of getting type 1 diabetes are being white and having islet cell antibodies in the blood.
Symptoms of diabetes are:
These symptoms usually appear over a few days to weeks. Sometimes people notice symptoms after an illness, like the flu. They may think that the diabetes symptoms are because of the flu, so they don't seek medical care soon enough.
If you wait too long to get medical care, you may get diabetic ketoacidosis, which is very dangerous. Symptoms of this problem include:
Your doctor can diagnose diabetes with a physical examination, your medical history, and blood tests.
Some people are diagnosed with type 1 diabetes because they have symptoms of diabetic ketoacidosis.
Treatment for type 1 diabetes focuses on keeping blood sugar levels within a target range and doing things to reduce complications. To control your blood sugar, you:
High blood sugar can lead to problems such as:
Health Tools help you make wise health decisions or take action to improve your health.
Type 1 diabetes develops because the body's immune system destroys beta cells in a part of the pancreas called the islet tissue. These beta cells produce insulin. So people with type 1 diabetes can't make their own insulin.
The pancreas normally adjusts the amount of insulin it makes based on your changing blood sugar. When you have diabetes, your insulin injections can't control your blood sugar moment to moment, the way your pancreas would. So you may have high and low blood sugar levels from time to time.
Causes of high blood sugar include:
Sometimes a person's blood sugar level rises greatly before he or she knows something is wrong. Because insulin isn't available, the cells in the body are unable to get the sugar (glucose) they need for energy. The body begins to break down fat and muscle for energy.
When fat is used for energy, ketones—or fatty acids—are produced and enter the bloodstream. This causes the chemical imbalance diabetic ketoacidosis. This can be a life-threatening condition.
Causes of low blood sugar include:
Symptoms of type 1 diabetes usually develop quickly, over a few days to weeks, and are caused by high blood sugar. At first, symptoms may be overlooked or mistaken for another illness, like influenza (flu).
High blood sugar symptoms include:
See more about symptoms of high blood sugar.
Symptoms of diabetic ketoacidosis are:
Common symptoms of low blood sugar include:
You can pass out when your blood sugar gets very low.
See more about symptoms of low blood sugar.
If you aren't able to tell when your blood sugar is too low (hypoglycemic unawareness), it's a good idea to test your blood sugar often.
It's not possible for injected insulin to work as well as a normal pancreas, so you will have high and low blood sugar levels from time to time.
If your blood sugar stays above your target range for a long time, it can damage many parts of your body.
High blood sugar levels can lead to vision loss and blindness (diabetic retinopathy).
To learn more, see the topic Diabetic Retinopathy.
Having diabetes also puts you at risk for cataracts or glaucoma.
You may have less feeling in your feet, which means that you can injure your feet and not know it. Common infections from blisters, ingrown toenails, small cuts, or other problems can quickly become more serious when you have diabetes.
If you get serious infections or bone and joint deformities, you may need surgery (even amputation) to treat those problems.
High blood sugar damages the lining of large blood vessels. This can lead to stroke, heart attack, or peripheral arterial disease.
High blood sugar levels can damage nerves throughout your body. This damage is called diabetic neuropathy. There are three kinds of diabetic neuropathy:
To learn more, see the topic Diabetic Neuropathy.
The kidneys have many tiny blood vessels that filter waste from your blood. High blood sugar can destroy these blood vessels. You won't have any symptoms of kidney damage until the problem is severe. Then you may notice swelling in your feet or legs or all over your body.
To learn more, see the topic Diabetic Nephropathy.
High blood sugar can damage the small blood vessels and nerves in the ear, causing hearing loss.
Gum disease can make it harder to keep blood sugar in a target range. And high blood sugar can cause gum disease, loss of teeth, and healing problems in the mouth.
The stress of dealing with diabetes or the effects that diabetes has on your body can lead to depression.
Being depressed can make it hard to eat healthy foods and to find the motivation to exercise. All of these things lead to higher blood sugar. By getting help for depression, you'll feel better and may find it easier to stay motivated.
Risk factors are things that increase your chances of getting sick or having a problem. Risk factors for type 1 diabetes include:
Call 911 or other emergency services right away if:
Call a doctor if:
Check with your doctor if:
Health professionals who may be involved in your diabetes care include:
If you have signs of complications of diabetes, such as nerve problems or kidney problems, you may be referred to a specialist. Learn more about the roles of the health professionals on a diabetes care team.
Women who want to plan a pregnancy need to talk to their doctors about making sure they have good control of their blood sugar.
High blood sugar levels during the first trimester of pregnancy raise the risk of birth defects. Good care of diabetes before conception appears to reduce the risk of birth defects.
Women with diabetes who don't want to be become pregnant should use birth control. This reduces the risk of birth defects in unplanned pregnancies.
If your doctor thinks that you may have diabetes, he or she will order blood tests to measure how much sugar is in your blood. The tests used are:
Your doctor will use your blood test results and criteria from Diabetes Canada to diagnose diabetes. He or she will also do a medical history and physical examination.
If it is hard to tell if you have type 2 or type 1 diabetes, your doctor may do a C-peptide test or test for autoantibodies. (Autoantibodies are produced when the body's immune system does not work right.) These tests can help diagnose type 1 diabetes.
There are several types of autoantibodies, and some people may have them even before they show symptoms of type 1 diabetes. For people with a parent or sibling with type 1 diabetes, testing for autoantibodies and a higher-than-normal blood sugar level may be done to screen for an early stage of type 1 diabetes.
Some rare forms of diabetes (not type 1 or type 2 diabetes) are caused by a genetic problem and may need genetic testing to diagnose them.
You'll need to see your doctor every 3 to 6 months. At your visits, your doctor may:
Regular visits and checkups with your doctor are also a good time to:
These visits are also a good time to talk with your doctor about how you're feeling. It's normal to feel frustrated or overwhelmed with all there is to do. If you're having trouble coping, your doctor can help.
If you have type 1 diabetes, your doctor may recommend these tests.
See a list of tests to monitor diabetes to help you remember what to do and when.
If you are a woman with diabetes who is planning to become pregnant, meet with your doctor before you get pregnant. Your diabetes puts your developing baby at risk for birth defects.
Type 1 diabetes requires treatment to keep blood sugar levels within a target range. Treatment includes:
Blood sugars are easier to predict and control when mealtimes, amounts of food, and exercise are similar every day. So getting into a daily routine helps a lot.
Some people find out that they have type 1 diabetes when they are admitted to a hospital for diabetic ketoacidosis. If their symptoms are severe, they may need to be treated in an intensive care unit.
Treatment for diabetic ketoacidosis includes fluids given through a vein (intravenous, or IV) to treat dehydration and to balance electrolytes, and insulin to lower the blood sugar level and stop the body from producing ketones.
If your blood sugar levels return to the normal range soon after diagnosis, you are in what is called the "honeymoon period."
This is a time when the remaining insulin-producing cells in your pancreas are working harder to supply enough insulin for your body.
Treatment during this time may include:
Currently there is no way to prevent type 1 diabetes, but ongoing studies are exploring ways to prevent diabetes in those who are most likely to get it. People who have a parent, brother, or sister with type 1 diabetes and are willing to participate in one of these studies should talk with their doctors.
People who have type 1 diabetes can help prevent or delay the development of complications by keeping their blood sugar in a target range. They also need regular medical checkups to detect early signs of complications. If complications are treated early, the damage may be stopped, slowed, or possibly reversed.
People who have other health problems along with diabetes, such as high blood pressure or high cholesterol, need to treat those conditions. Also, not smoking can reduce the risk of complications. Having other health problems can increase the risk for complications from diabetes.
Get a flu vaccine every year. When you have the flu, it can be harder to manage your blood sugar. It's a good idea to get a pneumococcal vaccine for pneumonia.
You may need or want additional immunizations if certain situations raise your chance for exposure to disease.
Type 1 diabetes requires daily attention to diet, exercise, and insulin. You may have times when this job feels overwhelming, but getting into a daily routine can help. And taking good care of yourself will also help you feel better, have a better quality of life, and prevent or delay complications from diabetes.
Carbohydrate is the one nutrient in your diet that most affects blood sugar levels. A registered dietitian can help you learn about what foods contain carbohydrate and how to manage it in your diet.
You need to take injections every day, because your pancreas no longer produces insulin. To learn more, see Medications.
Your doctor will want you to test your blood sugar level several times a day.
It's also important to know how to recognize and treat high or low blood sugar quickly.
Try to get at least 2½ hours of moderate to vigorous activity spread over at least 3 days that are not in a row. It's fine to be active in blocks of 10 minutes or more throughout your day and week.footnote 1
If your doctor says it's okay, do muscle-strengthening exercises 2 times a week and aim for 3 times a week.footnote 1 These exercises include push-ups and weight training. You can also use rubber tubing or stretch bands. You stretch or pull the tubing or band to build muscle strength. Be sure to work the major muscle groups: legs, hips, back, abdomen, chest, shoulders, and arms.
Exercise safely. Drink plenty of water before, during, and after you are active. This is very important when it's hot out and when you do intense exercise. You can also try keeping track of your exercise on an activity log .
Daily foot care can prevent serious problems. Foot problems caused by diabetes are the most common cause of amputations.
In addition to exercising, it is a good idea to limit the amount of alcohol you drink. In general, limit how much you drink. Canadian health experts recommend that:footnote 2
On special occasions every now and then, it's okay to have 1 extra drink.
One drink is 341 mL (12 fl oz) of beer, 142 mL (5 fl oz) of wine, or 43 mL (1.5 fl oz) liquor.
If you choose to drink, keep the amount of alcohol you drink within the recommended limits. Drinking at the upper limits should only happen once in a while, not every day or week. And on at least a couple of days each week, don't drink any alcohol at all. For more information, see the topic Alcohol: Drinking and Your Health.
Having type 1 diabetes can cause a lot of problems in your body. Smoking can make many of these problems worse, especially heart and blood vessel disease.
Smoking raises your cholesterol and makes it harder for your body to heal.
No matter how long you've smoked, your health will improve after you quit.
Insulin helps keep your blood sugar level tightly controlled and within a target range. It can be taken by an injection or through an insulin pump.
Usually people who have type 1 diabetes take a combination of types of insulin, such as a long-acting insulin once or twice a day and a rapid-acting insulin before each meal. The amount and type of insulin needed varies for each person.
The amount and type of insulin you need changes over time, depending on age, hormones (such as during rapid growth or pregnancy), and changes in exercise routine. You may need higher doses of insulin during times of illness or emotional stress.
Learn about insulin:
If small amounts of protein are found when your urine is tested, you may be in the early stage of diabetic nephropathy. You may be given an angiotensin-converting enzyme (ACE) inhibitor or an angiotensin II receptor blocker (ARB).
If you have talked about it with your doctor, take a low-dose aspirin every day. Aspirin can help certain people lower their risk of a heart attack or stroke. But taking aspirin isn't right for everyone, because it can cause serious bleeding. Do not start taking daily aspirin unless your doctor knows about it.
You may need one or more medicines to lower blood pressure.
You also may need to take medicine to lower your cholesterol.
Treating high blood pressure and high cholesterol may help prevent complications from diabetes.
You may need other medicines if you develop complications, such as kidney disease.
Some complications from type 1 diabetes are treated with surgery. For example, surgery to remove the vitreous gel (vitrectomy) may improve eye disease.
For more information, see:
When insulin isn't enough to keep blood sugar in your target range, a pancreas transplant might be an option. If it's successful, you may no longer have symptoms or need to treat diabetes.
But you may still get complications from diabetes. If you already have complications, they may continue to get worse as time goes on.
The success rate for pancreas transplants is improving because of new surgical techniques and new medicines.
If you get a transplanted pancreas, you must take medicine to keep your body from rejecting the new organ.
A pancreas transplant can be done at the same time as a kidney transplant.
Pancreatic islet cell surgery
Research continues on pancreatic islet cell surgery. It involves inserting a small group of donated pancreas cells (islet cells) through a vein in your liver. After surgery, these cells begin making insulin. If they can make enough, you may no longer need insulin injections.
Because the surgery is simpler than a pancreas transplant, there are usually fewer complications. But you must still take medicine to prevent rejection.
Avoid products that promise a "cure" for diabetes. For example, antioxidant supplements (vitamins E, C, and carotene) don't cure diabetes. Diabetes Canada doesn't recommend taking them.footnote 3
If you hear about something new to help diabetes, do some research to find out if it really works. You can also check with your doctor or a diabetes educator. Your health plan may also provide health information on its website.
Some complementary therapies may help relieve stress and muscle tension. They might help you feel better in general. But they shouldn't be used instead of treatment.
Talk with your doctor if you are using:
CitationsDiabetes Canada Clinical Practice Guidelines Expert Committee, et al. (2018). Physical activity and diabetes. Canadian Journal of Diabetes, 42(Suppl 1): S54–S63. DOI: 10.1016/j.jcjd.2017.10.008. Accessed October 15, 2018.Butt P, et al. (2010). Alcohol and Health in Canada: A Summary of Evidence and Guidelines for Low-Risk Drinking. Ottawa, ON: Canadian Centre on Substance Abuse. http://www.ccsa.ca/Resource%20Library/2011-Summary-of-Evidence-and-Guidelines-for-Low-Risk%20Drinking-en.pdf. Accessed September 19, 2018.Diabetes Canada Clinical Practice Guidelines Expert Committee, et al. (2018). Complementary and alternative medicine for diabetes. Canadian Journal of Diabetes, 42(Suppl 1): S154–S161. DOI: 10.1016/j.jcjd.2017.10.023. Accessed October 15, 2018.Other Works ConsultedAmerican Diabetes Association (2013). Nutrition therapy recommendations for the management of adults with diabetes. Diabetes Care, 36(11): 3821–3842. DOI: 10.2337/dc13-2042. Accessed December 5, 2013.De Ferranti SD, et al. (2014). Type 1 diabetes mellitus and cardiovascular disease: A scientific statement from the American Heart Association and American Diabetes Association. Diabetes Care, published online August 11, 2014. DOI: 10.2337/dc14-1720. Accessed September 4, 2014.Giovannucci E, et al. (2010). Diabetes and cancer: A consensus report. Diabetes Care, 33(7): 1674–1685. Also available online: http://care.diabetesjournals.org/content/33/7/1674.full?sid=ccc0c9ea-6728-4ebc-ae85-d2eaa4f2a6ee.Handelsman Y, et al. (2015). American Association of Clinical Endocrinologists and American College of Endocrinology—Clinical practice guidelines for developing a diabetes mellitus comprehensive care plan—2015. Endocrine Practice, 21(Suppl 2): 1–87. Available online: https://aace.com/files/dm-guidelines-ccp.pdf. Accessed April 23, 2015.Nix S (2013). Diabetes mellitus. In Williams' Basic Nutrition and Diet Therapy, 14th ed., pp. 400–425. St. Louis: Mosby.Pignone M, et al. (2010). Aspirin for primary prevention of cardiovascular events in people with diabetes: A position statement of the American Diabetes Association, a scientific statement of the American Heart Association, and an expert consensus document of the American College of Cardiology Foundation. Circulation, 121(24): 2694–2701.Skyler JS, et al. (2009). Intensive glycemic control and the prevention of cardiovascular events: Implications of the ACCORD, ADVANCE, and VA Diabetes Trials: A position statement of the American Diabetes Association and a scientific statement of the American College of Cardiology Foundation and the American Heart Association. Diabetes Care, 32(1), 187–192.U.S. Department of Health and Human Services (2008). 2008 Physical Activity Guidelines for Americans (ODPHP Publication No. U0036). Washington, DC: U.S. Government Printing Office. Available online: http://www.health.gov/paguidelines/guidelines/default.aspx.Vijan S (2014). Diabetes: Treating hypertension. BMJ Clinical Evidence. http://clinicalevidence.bmj.com/x/systematic-review/0608/overview.html. Accessed April 14, 2016.
Adaptation Date: 3/22/2021
Adapted By: Alberta Health Services
Adaptation Reviewed By: Alberta Health Services
To learn more about Healthwise, visit Healthwise.org.
© 1995-2021 Healthwise, Incorporated. All rights reserved. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.