What Causes Type 2 Diabetes Mellitus?


Type 2 diabetes is the fastest-growing chronic health condition in Australia, with one person being diagnosed every 5 minutes. According to Diabetes Australia, it’s the epidemic of the 21st century, and the biggest challenge currently facing Australia’s public health system (1). So, what exactly is this condition, and what causes Type 2 Diabetes Mellitus? Our Dietitian and Health Coach explains below.

First of all, what is type 2 diabetes?

Type 2 diabetes is a complex medical condition that typically develops over a long period of time, and occurs when your blood glucose (sugar) levels are higher than normal. Glucose is the main source of fuel (energy) used by the body and comes mainly from carbohydrate foods such as fruit, starchy vegetables, bread, rice, pasta, milk, yoghurt, sweets, and more (2). When you consume these types of foods, it travels to the stomach, where it is broken down into glucose and moved into the bloodstream. The presence of glucose in the bloodstream then triggers the beta cells within the pancreas to secrete a hormone called Insulin, which helps move the sugar from our bloodstream into our cells (e.g our muscles and liver) to be used for energy (2).

When you have type 2 diabetes, your body becomes resistant to the effects of insulin, otherwise known as insulin resistance. This means a normal amount of insulin secreted by the pancreas is ineffective at managing the levels of glucose in your body. As a result, your pancreas responds by reducing more and more insulin in order to convert glucose to energy and maintain healthy amounts within the bloodstream   (2). This ‘overproduction’ of insulin takes its toll on the pancreas, and over a long period of time, the cells begin to wear out and can no longer produce enough insulin that is required. In fact, most people diagnosed with type 2 diabetes have already lost 50-70% functioning of their insulin-producing cells (2).

When too much glucose stays in your bloodstream, rather than being used for energy by your body, it can cause damage to various organs such as the heart, kidneys, brain, eyes, and feet if left untreated (2).

What causes Type 2 Diabetes Mellitus?

A common question we are frequently asked is “what causes type 2 diabetes mellitus? There is no single cause of type 2 diabetes, but rather a combination of genetic and lifestyle risk factors that can increase the likelihood of a person developing the condition (3,4). These are also known as non-modifiable and modifiable risk factors. Here are some insights on what causes type 2 diabetes mellitus.

T2DM causes – Non modifiable risk factors

These risk factors are the ones we are born with or have no control over, for example:

  • Age – your risk of type 2 diabetes increases as you age, particularly >40 years old
  • Family history – If you have a close biological relative with diabetes, this means your risk is significantly increased
  • Race and ethnicity – Research has found that certain ethnicities carry a higher risk of developing type 2 diabetes.

These include people who are of Aboriginal, Torres Strait Islander, Pacific Islander, or Maori descent, as well as people who are from Asia, The Middle East, North Africa, and Southern Europe

  • Gestational diabetes – Having gestational diabetes during pregnancy increases the likelihood of developing type 2 diabetes in the future
  • PCOS – women who have been diagnosed with Polycystic Ovarian Syndrome are at higher risk due to Insulin Resistance (3,4)

T2DM causes – modifiable risk factors

These risk factors are mainly attributed to lifestyle, and can be changed, for example:

  • Being overweight – this is one of the largest risk factors of what causes type 2 diabetes mellitus
  • Fat distribution i.e. carrying more weight around your midsection
  • Having an inactive lifestyle – this is another huge risk factor of what causes type 2 diabetes mellitus
  • Blood lipid levels – specifically low HDL “helpful” cholesterol and high triglycerides increase your risk
  • High blood pressure
  • Smoking (3,4)

Want to know your risk? Answer 10 short questions on the diabetes risk calculator here (5).

Can type 2 diabetes be prevented?

In short – yes! As lifestyle choices are big contributors to what causes type 2 diabetes mellitus, there are many changes you can make to your lifestyle to prevent type 2 diabetes, or reduce your risk. In fact, large-scale randomised control trials have shown that type 2 diabetes can be delayed, or even prevented in up to 58% of cases just by following a healthy eating plan, being physically active, and by maintaining a healthy weight (6).

Here are the major ways in which type 2 diabetes can be prevented or delayed:

  • Eating a nutritious, balanced diet including a variety of fruit, vegetables, legumes, whole grains, lean meats, and reduced-fat dairy products

  • Aiming for a healthy body weight
  • Increasing physical activity
  • Managing blood pressure and cholesterol levels
  • Reducing alcohol consumption
  • Quitting smoking

Is there a cure for type 2 diabetes?

Unfortunately, there is no cure for type 2 diabetes (7). However, your blood sugar levels can be well managed to the point where your condition can be classified as being “in remission” through healthy eating and regular exercise. If these lifestyle changes aren’t enough to manage the disease, you may be required to take oral medications and or insulin therapy in combination with lifestyle changes (7).

The take-home message

In summary, there is no single cause of type 2 diabetes, but rather a combination of genetic and lifestyle factors. If you’re worried about your risk and are looking to prevent type 2 diabetes, or are looking to reverse type 2 diabetes, we are here to help you.

At Diabetes Wellness Australia, we offer individualised, evidence-based programs designed to help you prevent type 2 diabetes, or reverse the disease. Book your free assessment to speak to one of our friendly staff today about how our supportive programs can help you.

How we reviewed this article:
  • Sources
  • History

Our team consistently oversees developments in the health and wellness sector, ensuring our articles are updated with the latest information as soon as it emerges.

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