What is type 2 diabetes and how can it be prevented?

People with diabetes are at a higher risk of health problems such as heart attacks, strokes and blindness. So what causes diabetes? And can you prevent it by changing what you eat?

Physician and scientist Professor Merlin Thomas explains how type 2 diabetes works and how you can lower your risk of developing it.

Far too many people have diabetes. In 2017 the International Diabetes Federation estimated that nearly half a billion people worldwide had the condition. In the future, they predict there will be many more.

Put another way, experts say at least one in three adults will develop diabetes as they get older, potentially costing them both their health and longevity.

But for the same reasons our modern diet and lifestyle is making type 2 diabetes more common, such as insufficient physical activity and a higher intake of unhealthy foods, in many cases it can also be prevented.

What is diabetes?

Type 2 diabetes
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Diabetes is a syndrome in which blood glucose levels become elevated to cause health problems. Glucose levels are normally kept under tight control, mainly through the actions of the hormone, insulin. Diabetes happens when your body can’t make enough insulin to keep glucose levels down.

In the long term, high glucose levels are a leading cause of heart disease, vision loss, amputations, kidney failure and severe infections.

What are the different types of diabetes?

There are three main types of diabetes – type 1, type 2 and gestational diabetes.

Type 1 diabetes

In type 1 diabetes, the immune system destroys the insulin-producing cells of the pancreas that are essential for glucose control. This means that life-long insulin injections are needed to survive. Latest ABS figures show that type 1 diabetes affects at least 145,000 Australians.

Gestational diabetes

In gestational diabetes, some women cannot make enough insulin to overcome the natural resistance to insulin’s actions that happens during their pregnancy. This means blood glucose levels can rise dangerously for both the mother and baby. Gestational diabetes now occurs in one in seven pregnancies globally.

Although gestational diabetes usually goes away once the baby is delivered, some women who have had it may also get it in subsequent pregnancies. Importantly, over half of women who have had gestational diabetes will develop type 2 diabetes over their next 20 years.

Type 2 diabetes

Type 2 diabetes is by far the most common form of diabetes today. Over 1.1 million Australians with type 2 diabetes are currently registered with the National Diabetes Support Scheme (NDSS) and there may be others with type 2 diabetes outside the scheme.

Let’s take a closer look at some of the causes, symptoms and treatments for this most common type of diabetes.

What causes type 2 diabetes?

Diabetes and weight
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Like the other forms of the condition, type 2 diabetes develops because of the body’s failure to make enough insulin to control blood glucose levels.

However, in type 2 diabetes this is usually caused by having too much fat in your body. Your risk of developing diabetes in the next five years can be increased if your waistline is more than it should be:

  • greater than 102 cm (40 in) in men (Asian men: greater than 90 cm/35½ in)
  • greater than 88 cm (34½ in) in women (Asian women: greater than 80 cm/31½ in)

(Source: Australian Government Department of Health’s diabetes risk assessment tool)

Having too much fat in your body places a number of stresses on your health and wellbeing. One of these stresses is that the actions of insulin become partly blocked. If insulin production cannot increase enough to compensate, blood glucose levels eventually rise, resulting in type 2 diabetes.

Apart from your waistline, your age, ethnicity, diet, lifestyle, family history and early development can all influence if and when type 2 diabetes might occur.

What are some of the symptoms of type 2 diabetes?

High glucose levels usually start out as a silent problem or with mild symptoms like:

  • feeling tired and weak all the time
  • having difficulty concentrating
  • trouble with your eyesight and/or dry eyes
  • passing urine more frequently during the day and especially during the night

It’s easy to think that you’re just getting old, feeling overworked or stressed but it could be type 2 diabetes. So if you’re feeling some of these symptoms you may want to check with your doctor. Even if you are feeling perfectly well, it is recommended, for example by the Royal Australian College of General Practitioners, that all Australians should be screened for diabetes at least every three years by their GP from the age of 40. You can also consider taking the Department of Health’s risk assessment test.

Treating type 2 diabetes

People with type 2 diabetes are recommended to improve their diet and increase their level of physical activity. For people who are able to lose all their extra fat with the help of surgery or intensive weight loss diets, at least initially, glucose control can return to normal and type 2 diabetes can go away. This shows that excess fat is at the core of the type 2 diabetes in many cases. However, after a few years of having diabetes, the pancreas can become so damaged that even losing large amounts of fat can’t bring healthy glucose control back online.

Type 2 diabetes is usually a progressive condition, meaning it gradually gets worse over time. Most people who have it will eventually need pills and/or injections to keep their glucose levels from rising too high.

How to help prevent type 2 diabetes

type 2 diabetes
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The best time to deal with type 2 diabetes is well before you get it. You only gain fat when the food you eat contains more energy than you burn with your body’s activities. Prevention of type 2 diabetes is typically all about eating less and burning more to keep your weight down.

To burn more energy, you’ll generally need to spend less time sitting and more time being active and getting fitter. To eat less energy, you’ll need to change your diet to reduce the amount you eat as well as change the kinds of calorie-rich things you normally consume. Especially for those who are obese, losing your excess weight and keeping it off may improve your blood glucose control and make it less likely you develop type 2 diabetes.

Lifestyle choice recommendations

Preventing type 2 diabetes is not just about losing weight. A rich and varied diet containing foods that are naturally high in fibre and with a low glycaemic index (GI) can also be important for lowering your risk of type 2 diabetes. Equally, minimizing the amount of processed food you eat (particularly refined grains, added sugars and processed red meat) can be helpful.

You can try doing this yourself or more simply you can adopt an overall way of eating that includes these features. One example is going on the ‘Mediterranean diet’.  The Mediterranean diet is a diet traditionally followed in Greece, Crete, southern France, and parts of Italy. The diet emphasises fruits and vegetables, nuts, wholegrains, olive oil, grilled or steamed chicken and seafood, and a glass or two of red wine. Studies show that taking up the Mediterranean diet is associated with a 40% lower risk of developing type 2 diabetes.

It’s not the only way. Other approaches like low-carbohydrate and ketogenic diet, vegan diet, and low GI diets can also reduce your risk of developing type 2 diabetes. Equally, techniques like intermittent fasting, calorie counting and the use of psychology to help keep the dieter on track.

In the end, what is important is that you try to stay physically active, eat less and better food, and stick with it for the long term, rather than yo-yo-ing back to your old ways and old weight. Taken together, fixing your diet and lifestyle can be an investment in a healthier future.

Professor Merlin ThomasAbout Professor Merlin Thomas

Dr Merlin Thomas is a Professor in the Department of Diabetes at Monash University in Melbourne. His research is focused on discovering new ways to prevent and treat diabetes complications. Professor Thomas is the author of over 300 papers and books including “The Longevity List” and “Understanding Type 2 Diabetes”.


Image Source: Chinnapong (Shutterstock)

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