Boots WebMD Partners in Health
Return To Boots

Diabetes health centre

Select a topic to explore more.
Select An Article

Type 1 diabetes

A person with type 1 diabetes cannot produce insulin themselves, so needs to take insulin to manage their blood sugar levels.

Type 1 diabetes is known as an autoimmune condition, because the body's defences - the immune system - wrongly attacks the cells in the pancreas responsible for making insulin.

Although the condition usually appears before the age of 40 and more than half the people with type 1 are diagnosed under the age of 15, type 1 diabetes may occur at any age, according to Diabetes UK.

Type 1 diabetes is less common than type 2 diabetes and accounts for around 10% of people diagnosed with diabetes, according to Diabetes UK.

Insulin and type 1 diabetes

Normally, the hormone insulin is secreted by the pancreas. When you eat a meal, sugar (glucose) from food stimulates the pancreas to release insulin. The amount that is released is proportional to the amount that is required by the size of that particular meal.


Insulin's main role is to help move certain nutrients - especially sugar - into the cells of the body's tissues. Cells use sugars and other nutrients from meals as a source of energy to function.

The amount of sugar in the blood decreases once it enters the cells. Normally that signals the beta cells in the pancreas to reduce the amount of insulin secreted so that you don't develop low blood sugar levels ( hypoglycaemia). But the destruction of the beta cells that occurs with type 1 diabetes throws the entire process into disarray.

In people with type 1 diabetes, sugar isn't moved into the cells because insulin is not available. When sugar builds up in the blood instead of going into cells, the body's cells are starved of nutrients. This means other systems in the body must provide energy for many important bodily functions. As a result, high blood sugar develops and can cause:

  • Dehydration: The build-up of sugar in the blood can cause you to urinate more as the level of glucose exceeds that which the kidneys can reabsorb, and the resultant glucose in the urine draws water with it. When the kidneys lose the glucose through the urine, a large amount of water is also lost, which causes dehydration.
  • Unplanned weight loss: The loss of sugar in the urine means a loss of calories that provide energy. So, many people with high sugars lose weight. Dehydration also contributes to weight loss.
  • Diabetic ketoacidosis (DKA): Without insulin, and because the cells are starved of energy, the body breaks down fat cells. This produces acidic chemicals called ketones that can be used for energy. These ketones begin to build up in the blood and cause increased acidity. The liver continues to release the sugar it stores to help out. Since the body cannot use these sugars without insulin, more sugar builds up in the blood stream. The combination of high excess sugars, dehydration, and acid build-up is known as ketoacidosis. It can be life-threatening if not treated immediately.
  • Damage to the body: Over time, the high sugar levels in the blood may damage the nerves and small blood vessels of the eyes, kidneys, and heart. This can predispose a person to atherosclerosis (hardening and narrowing) of the arteries that can cause heart attacks and stroke.
Next Article:

WebMD Medical Reference

Popular slideshows & tools on BootsWebMD

How to help headache pain
rash on skin
Top eczema triggers to avoid
Causes of fatigue & how to fight it
Tips to support digestive health
woman looking at pregnancy test
Is your body ready for pregnancy?
woman sleeping
Sleep better tonight
Treating your child's cold or fever
fifth disease
Illnesses every parent should know
spoonfull of sugar
Surprising things that harm your liver
woman holding stomach
Understand this common condition
What your nails say about your health