Type 1 Diabetes
- Juliana Podobnik, MSc, MD(c)
- Mar 19
- 5 min read
What is Type 1 Diabetes?
Type 1 diabetes is a condition where the body can no longer produce insulin, a hormone that helps control the amount of sugar in the blood. It most often begins in childhood or adolescence, but it can develop at any age [1].
To understand type 1 diabetes, it helps to know how blood sugar normally works. When you eat, your body breaks food down into glucose, a type of sugar that travels through your bloodstream. Your pancreas, a small organ located behind your stomach, releases insulin to help move that glucose into your cells, where it is used for energy [1].
Think of insulin like a key that unlocks your cells so sugar can enter. In type 1 diabetes, the body’s immune system mistakenly attacks and destroys the insulin-producing cells in the pancreas. These cells are called beta cells. Once most of these cells are destroyed, the body can no longer make enough insulin [2].
Without insulin, glucose cannot move into the cells properly. Instead, it builds up in the bloodstream. This leads to high blood sugar levels, which can damage organs and tissues over time if untreated [1].
Type 1 diabetes is different from type 2 diabetes. In type 2 diabetes, the body still produces insulin but does not use it effectively. In type 1 diabetes, the body makes little or no insulin at all, so people must take insulin every day to survive [1].
Causes and Risk Factors
Type 1 diabetes is an autoimmune disease, meaning the immune system attacks the body’s own cells by mistake [2]. Scientists are still trying to understand exactly why this happens.
Several factors appear to play a role:
Genetics. Some people inherit genes that increase their risk of developing type 1 diabetes.
Environmental triggers. Certain viral infections may trigger the immune system to attack the pancreas in people who are genetically susceptible [3].
Family history. Having a close relative with type 1 diabetes slightly increases the risk, but many people diagnosed with the condition have no family history at all [3].
Unlike type 2 diabetes, type 1 diabetes is not caused by lifestyle factors such as diet, body weight, or physical inactivity.
Common Symptoms
Symptoms of type 1 diabetes often develop quickly, sometimes over just a few weeks. This happens because the body suddenly stops producing enough insulin.
Common symptoms include:
Frequent urination: High blood sugar causes the kidneys to remove extra glucose through urine.
Extreme thirst: Losing fluid through frequent urination makes people very thirsty.
Unexplained weight loss: Without insulin, the body cannot properly use glucose for energy and begins breaking down fat and muscle.
Severe fatigue: Cells are not receiving the energy they need.
Blurred vision: High blood sugar can affect fluid balance in the eyes
Increased hunger: Even though blood sugar is high, the cells are essentially “starving” for energy [4]
In some cases, the first sign of type 1 diabetes is a serious condition called diabetic ketoacidosis (DKA). This happens when the body breaks down fat too quickly for energy, producing acids called ketones. Symptoms may include nausea, vomiting, stomach pain, rapid breathing, confusion, and breath that smells fruity [4]. DKA is a medical emergency and requires immediate treatment.
How is Type 1 Diabetes Diagnosed?
Doctors diagnose type 1 diabetes using blood tests that measure blood sugar levels. Common tests include:
Fasting blood glucose test. After not eating for at least 8 hours, blood sugar levels are measured. A level of 7.0 mmol/L or higher suggests diabetes [5].
HbA1c test. This test shows the average blood sugar level over the past ~3 months. A result of 6.5% or higher usually indicates diabetes [5].
Random blood glucose test. If someone has symptoms of diabetes, a random blood sugar test can confirm the diagnosis if the level is very high [5].
Doctors may also run additional tests to confirm type 1 diabetes, such as checking for autoantibodies (proteins made by the immune system that attack the pancreas) or measuring levels of C-peptide, a marker of insulin production [6].
How is Type 1 Diabetes Treated?
People with type 1 diabetes must take insulin every day because their body cannot produce it.
Insulin can be given in several ways:
Insulin injections. Many people use insulin pens or syringes to inject insulin under the skin several times per day [6].
Insulin pumps. These small wearable devices continuously deliver insulin through a tiny tube placed under the skin [6]
Continuous glucose monitors (CGMs). These devices track blood sugar levels throughout the day and night, helping people adjust insulin doses more accurately [6].
Managing type 1 diabetes also involves:
Checking blood sugar regularly
Balancing insulin with food and physical activity
Learning how to count carbohydrates, which helps determine how much insulin is needed with meals
Regular medical check-ups to monitor the eyes, kidneys, nerves, and heart.
While type 1 diabetes currently has no cure, advances in treatment technology have made it much easier for people to live long and healthy lives with the condition.
Researchers are also studying promising future treatments, including beta-cell replacement therapies, islet cell transplants, immune-based therapies, and metabolism based therapies that may slow or prevent the disease [2,6].
When to Seek Medical Advice
You should seek medical care right away if you or someone you know develops symptoms of type 1 diabetes, especially:
Extreme thirst and frequent urination
Rapid weight loss without trying
Severe fatigue or weakness
Blurred vision
Nausea, vomiting, or stomach pain
These symptoms can develop quickly and may indicate dangerously high blood sugar or diabetic ketoacidosis.
Overall, early diagnosis and treatment of type 1 diabetes is essential. With proper care, people with type 1 diabetes can manage their blood sugar effectively and lead active, healthy lives.
Sources:
Henriques FL, Buckle I, Forbes JM. Type 1 diabetes mellitus prevention: present and future. Nature Reviews Endocrinology. 2025; 21:608–622. doi:10.1038/s41574-025-01128-6.
Atkinson MA, Eisenbarth GS, Michels AW. Type 1 diabetes. The Lancet. 2014; 383(9911):69–82. doi:10.1016/S0140-6736(13)60591-7.
Kostopoulou E, Sinopidis X, Fouzas S, Gkentzi D, Dassios T, Roupakias S, Dimitriou G. Diabetic ketoacidosis in children and adolescents: Diagnostic and therapeutic pitfalls. Diagnostics (Basel). 2023;13(15):2602. doi:10.3390/diagnostics13152602.
National Institute of Diabetes and Digestive and Kidney Diseases. Diabetes tests & diagnosis [Internet]. U.S. Department of Health and Human Services. Available from: https://www.niddk.nih.gov/health-information/diabetes/overview/tests-diagnosis
American Diabetes Association Professional Practice Committee. Diagnosis and classification of diabetes: Standards of care in diabetes. Diabetes Care. 2024; 47(Suppl 1):S20–S42. doi:10.2337/dc24-S002.
Podobnik J, Prentice KJ. Metabolic interventions as adjunctive therapies to insulin in type 1 diabetes: Current clinical landscape and perspectives. Diabetes, Obesity and Metabolism. 2025; 27(3):1032–1044. doi:10.1111/dom.16154.
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