What is insulin?

Insulin is a hormone made by the pancreas. It acts like a key, letting blood glucose (or ‘blood sugar’) enter the body’s cells to be used as energy. Without enough working insulin, or if insulin isn’t working properly, glucose stays in the blood, causing levels to rise.

Insulin can also be given as a medication to help manage diabetes. It is ‘bioidentical’, which means it works just like the insulin your body naturally makes.

Type 1 diabetes

Type 1 diabetes is an autoimmune condition where the body’s immune system attacks the insulin-producing cells in the pancreas. Over time, the pancreas stops making insulin, so the body cannot control blood glucose properly. People with type 1 diabetes need to take insulin daily, either via injections or an insulin pump.

It is not caused by lifestyle, although genetics and environmental factors play a role. There is currently no cure, so it is a lifelong condition.

Key facts

• Type 1 diabetes develops when the pancreas makes little or no insulin due to immune system attacks.
• It accounts for about 10% of all diabetes cases and is one of the most common long-term conditions in children.
• It’s most commonly diagnosed in children and young people under 30.
• Symptoms often appear suddenly in children but can develop slowly in adults. Common symptoms include excessive thirst, frequent urination, unexplained weight loss, fatigue, and blurred vision.
• Treatment involves taking insulin daily, either as multiple injections or via an insulin pump.
• While type 1 diabetes is highly nuanced and requires personalised care, people with type 1 can also develop insulin resistance. Dietary and lifestyle changes may help, but adjustments should always be made under medical guidance.

Prediabetes

Prediabetes is when blood glucose levels are higher than normal but not yet high enough to be called type 2 diabetes. It is a warning stage that type 2 diabetes is coming.

Key facts

• Prediabetes affects about 2 million people in Australia and over 1 million in New Zealand.
• Usually there are no symptoms, but watch for thirst, frequent urination, fatigue, or blurry vision.
• Risk factors are similar to type 2 diabetes: extra weight, physical inactivity, age over 45, and diet. Tools like AUSDRISK can help assess risk.
• Healthy eating, exercise, and weight loss can reverse prediabetes and prevent progression to type 2 diabetes.

Type 2 diabetes

Type 2 diabetes develops when the body’s cells stop responding properly to insulin, a condition called insulin resistance.

In the early stages, such as prediabetes, blood glucose levels begin to rise as the body becomes less sensitive to insulin. To compensate, the pancreas produces extra insulin. Over time, the pancreas can no longer keep up with this demand, and blood glucose levels remain high, leading to a diagnosis of type 2 diabetes.

Key facts

• Type 2 diabetes accounts for around 85–90% of all diabetes cases.
• It most commonly develops in adults over 45, but younger people, including adolescents, are increasingly affected.
• By the time of diagnosis, the pancreas has often lost 50–70% of its insulin-producing ability.
• Long-term corticosteroid use for other conditions can trigger or accelerate it in some people.
• The first signs can sometimes be complications, such as heart problems, blurred vision, or slow-healing wounds.
• Lifestyle and dietary changes, including regular physical activity and healthy eating, are the first-line management strategies.
• If the condition progresses, medications or insulin may become necessary.

Type 1.5 diabetes

Type 1.5 diabetes, or Latent Autoimmune Diabetes in Adults (LADA), is an autoimmune form of diabetes that develops slowly in adults. Like type 1, the immune system attacks insulin-producing cells, but insulin production declines gradually, so early symptoms can resemble type 2 diabetes.

Key facts

• LADA affects around 4–14% of people initially diagnosed with type 2 diabetes.
• It most commonly occurs in adults over the age of 30–35.
• People may also have other autoimmune conditions, such as thyroid disease.
• Diagnosis requires blood tests for autoantibodies (to indicate the immune system is attacking the pancreas) and C-peptide tests (to measure remaining insulin production).
• Lifestyle changes help manage blood glucose early, but insulin therapy is often needed as pancreatic function declines.

Monogenic diabetes

Monogenic diabetes, or Maturity-Onset Diabetes of the Young (MODY), is a rare form of diabetes caused by a mutation in a single gene. It is inherited in families—if a parent carries the mutation, each child has a 50% chance of developing it. MODY accounts for around 2% of all diabetes cases.

Read more about MODY here or listen to this podcast episode.