Diabetes is a big health issue in New Zealand. It’s also growing, and it affects us all. Senior nutritionist Rose Carr tells us why.
At the end of 2014 it was estimated that 257,700 New Zealanders – or six per cent of the population – were living with diabetes. During that year the number of people with diabetes grew by nearly 40 people per day. About 90 per cent of people with diabetes have type 2 diabetes (see box ‘Different types of diabetes’ on page 33), but rates of type 1 diabetes and gestational diabetes are also increasing.
The prevalence of diabetes is increasing across all ethnic groups and age groups. In fact, the largest percentage increases in diabetes are among adults aged 25–44 years, and at least one in six adults aged 65 years and over has diabetes. However, some groups are affected more than others. Data from 2013 found the highest rate of diabetes was in the Indian ethnic group (11 per cent), followed by Pacific peoples (9.6 per cent). The prevalence of diabetes is also higher in Maori and people living in lower socioeconomic areas.
Different types of diabetes
Type 2 diabetes
Accounts for around 90–95 per cent of diabetes in New Zealand. Usually, but not always, it’s a disease of our lifestyle; it’s strongly associated with overweight and obesity, a poor diet and a lack of physical activity.
Type 2 diabetes is a metabolic condition where over time insulin production becomes inadequate or body cells become resistant to insulin, or both. Once referred to as ‘adult-onset’ diabetes there are now many cases in children under 15 years old.
Type 1 diabetes
Accounts for around 5–8 per cent of cases. It’s an autoimmune disease where the immune system destroys the cells in the pancreas that produce insulin so they produce little, if any, insulin.
Type 1 diabetes usually develops in childhood or adolescence, but onset can occur at any age. Genetics may play a role in developing type 1 diabetes but it’s not really known what causes it and there is no cure. People with type 1diabetes use insulin to keep their blood glucose levels within a set range.
A temporary form of diabetes that can occur during pregnancy when insulin needs are two to three times higher than before the pregnancy. Women who have had gestational diabetes have a 50–60 per cent higher risk of developing type 2 diabetes later on.
Who’s at risk of developing type 2 diabetes?
We’re at greater risk if we:
- are obese
- have a family history of early-onset type 2 diabetes in more than one first-degree relative
- are a woman who has had gestational diabetes
- are a woman with polycystic ovary syndrome (PCOS)
- have ischaemic heart, cerebrovascular or peripheral vascular disease
- are on long-term steroid or anti-psychotic treatment
- experience severe mental illness and/or addiction
Prediabetes: the new epidemic
Prediabetes, sometimes called insulin resistance, is just what it sounds like: the precursor to type 2 diabetes. As in if nothing changes, you’re heading for type 2 diabetes. The 2008/09 Adult Nutrition Survey found that, in addition to those with diabetes, a whopping 18.6 per cent of adults had prediabetes – that’s nearly one in five!
In addition to the risk factors listed on page 32, the conditions that predispose us to prediabetes are what we might well call ‘the usual suspects’, namely:
- overweight (especially around the midsection)
- high blood pressure
- high cholesterol
We can see why prediabetes and type 2 diabetes are called lifestyle diseases. But there is good news about prediabetes: make some changes and you could avoid getting diabetes.
What are the consequences?
Many of us know people with diabetes who look just fine, so we might not realise why diabetes is so serious. It’s important that blood glucose levels are managed, as the long-term consequences of diabetes can be severe. For people with prediabetes and for some with type 2 diabetes, a healthy diet and plenty of exercise can be enough; for others, medication is needed.
Early detection and good management of blood glucose helps to delay or even prevent long-term complications, which can include:
- blindness and nerve damage
- heart disease, stroke, kidney disease, periodontal disease
- amputation of a foot or lower leg, dialysis, kidney transplants, loss of teeth
- reduced life expectancy
How to avoid getting type 2 diabetes
Even if you’ve been told you have prediabetes, it’s not too late to make some changes to help avoid getting type 2 diabetes. If you smoke, stop now. See www.quit.org.nz.
Reduce your risk of developing type 2 diabetes by around 60 per cent by losing weight (if overweight), exercising regularly and eating a healthy diet. This may not be easy, but remember, making these changes can make your body and mind feel a whole lot better.
1. Lose weight
For people who are overweight, weight loss is the most important of these action points, but of course exercise and a healthy diet will help, too.
- Review your portion sizes. Use smaller plates to help keep them in check.
- Include foods in meals and snacks that keep you full.
- Fibre and protein are your friends. You’ll find fibre in whole foods, so avoid overly-processed packaged or takeaway foods.
- Eat more non-starchy, colourful veges. And don’t overdo the carbs. Aim to have half a plate of low-energy veges, quarter with protein foods and the remaining quarter with carbs.
2. Up the exercise
There’s strong evidence that physical activity improves insulin sensitivity and reduces the risk of developing type 2 diabetes. And the great news is that all types of activity help, whether you like to go hard out or prefer a more leisurely pace.
- If you don’t normally exercise, start today! Start with a 20-minute walk and build up to longer walks over time. Getting some baseline fitness can also provide confidence to try other things.
- Aim to be active in some way every day. Make it a habit rather than having to think about it every day.
- Gyms are great, but they’re not for everyone. Think gardening, cycling, dancing, housework or Zumba classes.
- It doesn’t have to take an hour out of every day. Short bursts of high-intensity exercise have been shown to be really effective in improving health. For example, you could try 10 minutes of running hard out (on a treadmill or outdoors), or 10 minutes fast skipping.
- Add incidental exercise. Use the stairs instead of the lift and walk instead of taking the car on a short journey.
3. Watch the diet
Maintaining a healthy weight is really important, as excess weight affects both blood pressure and cholesterol levels. But what we choose to eat affects these as well.
- Check the sodium content of packaged foods. Choose those lower in sodium.
- Eat more low-energy veges.They’re full of potassium so are good for blood pressure.
- Limit saturated fats. These can clog our arteries. Always choose lean meats or trim excess fat.
- Focus on carbohydrate quality (give the cakes and donuts a swerve) and quantity (keep the carb portion down at meals).
What’s age got to do with it?
As we age we are at greater risk of developing insulin resistance and type 2 diabetes, however the reasons for this are not entirely clear. Originally scientists thought the increasing insulin resistance was because as we get older we tend to put on weight, lose lean muscle mass, reduce physical activity and maybe change our dietary habits. However, the research has found that while these factors don’t help, they do not account for age-related insulin resistance by themselves. Animal studies suggest that the number of cells in the pancreas producing insulin (beta cells) declines as we age, and the beta cells we do have may not produce as much insulin.
Here’s the good news: Researchers at the Diabetes Prevention Program in the US have found that diet and exercise can be very effective in preventing diabetes in people aged 60–85 years. In fact, compared to using the drug Metformin, the combination of losing weight and increasing physical activity was far more effective in diabetes prevention. They hypothesise that the limited effectiveness of Metformin in older people may be due to age-related differences in insulin action and secretion.
What about a low-carb diet?
When we eat foods containing carbs they’re broken down into glucose, which is taken into our bloodstream. Insulin is then needed to help get the glucose into the cells where it’s to be used. So if we can’t produce enough insulin, or we’re insulin- resistant, then limiting the amount of glucose in our blood to start with seems logical. And to do that, all we have to do is cut back on the carbs. But should we?
A 2015 study published in the American Journal of Clinical Nutrition compared a diet with 14 per cent energy from carbs to one with 53 per cent. The very low-carb diet had a higher protein content but was particularly high in fat – notably healthy unsaturated fats rather than saturated fat. Over a 12-month period, both of these kilojoule-controlled diets achieved similar weight loss in the obese clients with type 2 diabetes, as well as better HbA1c. The very low-carb diet achieved better results for triglycerides, HDL cholesterol and glycaemic control. Although there’s a lot more research going on, there are other studies showing that very low-carb diets can be effective in managing glucose and improving blood fats in people with type 2 diabetes.
If we reduce carbs in the diet, it’s important not to increase saturated fats. We also need to ensure we get adequate intakes of different types of fibre. Remember that as well as glucose, carbs are an important source of fibre in our standard diet. A low-carb high-fat diet may be a dietary pattern some people enjoy. For others it’s too expensive and not especially palatable. Like any diet that’s radically different to our normal way of eating, it may also take some expertise to ensure the diet provides everything you need. And, of course, anyone currently on medication for diabetes needs to talk to their diabetes dietitian or GP before making changes to their carb intake.
Professor Jim Mann, Director of the Edgar Diabetes and Obesity Research unit, says there is actually a very wide range of carbohydrate intake that’s acceptable, but the crucial point is the type of carbs we eat. Choosing high-fibre, low-GI carbs has been shown to be good for blood glucose management; choosing high-GI, low-fibre carbs is not. He recommends legumes and genuine wholegrains as the best options. Many breads and cereals try to look grainy, but are little better than white bread. And white rice, potato and other starchy vegetables need to be limited. He suggests for people with, or at risk of, type 2 diabetes as little as 35 per cent energy from carbs can be helpful. Remember, total energy intake (kilojoules) needs to be controlled as well.
What the numbers mean
The HbA1c (glycalated haemoglobin) test is used to screen for type 2 diabetes. HbA1c indicates the average blood glucose levels over the previous six to eight weeks.
- HbA1c = 50 mmol/mol indicates probable diabetes (but does not confirm a diagnosis by itself)
- HbA1c 41–49 mmol/mol suggests prediabetes/insulin resistance
- HbA1c = 40 mmol/mol is normal
Five diabetes myths and truths
1. Too much sugar causes type 2 diabetes
Wrong. It’s true that carrying excess weight is an important risk factor for type 2 diabetes, but it doesn’t matter what type of food you consumed to get there.
2. Diabetes is not that serious
Don’t kid yourself. If you don’t manage blood glucose levels, the long-term complications can include blindness and amputations.
3. Only fat people get type 2 diabetes
No. There is a genetic factor as well, so some people with type 2 diabetes may never have been overweight.
4. People with diabetes can never eat sweet treats
Not true. But portion size is important for all of us, and especially important for people with medicated diabetes.
5. Exercise is dangerous if you have diabetes
On the contrary, regular exercise helps blood glucose control. But if you’re just starting, or upping the exercise, talk to your doctor first.
The 8-Week Blood Sugar Diet
In March 2016 Dr Michael Mosley was here from the UK to promote his latest diet book, The 8-Week Blood Sugar Diet. (While he qualified as a doctor it’s probably worth knowing he never practised as one. He went to work for the BBC instead.) His first book, The FastDiet, focused on the 5:2 way of eating for weight loss, where you restrict energy intake to around 3400kJ (800 calories) for two days each week.
This new book presents a diet plan based on consuming around 3400kJ every day for eight weeks. Basically, it can be described as the very low-carb diet meets the very low-kilojoule diet. He also suggests that if you find the diet too hard, or you don’t feel well on it, then you could try following it only two days each week.
Diet books sell because they promise great results. And they keep on selling because people hope the next diet will work when the last one didn’t. This is a radical diet and while it might suit some highly motivated people, we don’t think there would be many who could sustain this way of eating for eight weeks.
Case study: “I was in diabetes denial”
Twenty years ago, after a lifelong struggle with obesity, Julie Langlois was diagnosed with type 2 diabetes.
Tablet medication (Metformin) was prescribed. Despite doctors advising her to lose weight to manage her blood sugars, Julie continued to get bigger.
Over time she became very unwell from poorly managed diabetes, and had classic symptoms: excessive thirst, a constant need to urinate, and fatigue. “I was always tired and thought it was because I was overweight.” She also lost the feeling in two of her toes (diabetic peripheral neuropathy) and suffered blurry vision.
Eventually she was hospitalised with a dangerously high blood sugar level. “The specialist told me I had to drastically change my lifestyle or I wouldn’t be here to see my children grow up.”
The doctor also prescribed insulin to get her diabetes under control, which Julie fought against “hammer and tongs”. She now realises this was ‘diabetes denial’: a common problem when people don’t want to face their condition.
Despite the health crisis Julie made only a few changes to her lifestyle, and resisted taking blood tests to measure her blood sugar levels. She admits she used insulin to try to control her blood sugars when she ate too many carbohydrates.
It was only after becoming concerned about her husband’s weight that she managed to get her head “in the right space” to take drastic action to lose weight and tackle her diabetes.
She and her husband joined Weight Watchers and started walking for an hour five times a week. At first Julie was so ashamed of her size that she would walk only at night. The couple also joined the gym. They also moved closer to their workplaces so they didn’t have long commutes that saw them so tired they’d buy takeaways four times a week.
Now they both arrive home and get out walking “no matter what”, before Julie cooks a healthy meal for dinner.
Two years later, Julie has lost 56kg (down from 131kg) and her husband 30kg. She used to wear size 26 trousers but is now a size 10. She is off insulin and only takes Metformin. She’s been told she could stop taking this soon.
Not having to plan her life around taking insulin four times a day is a relief. She’s now full of energy and feels healthy and well. Her advice to people is to get into the right frame of mind and get as much help as possible. “You have to have your head in the right space. You need to have a lot of constant support. I needed someone to help me, and I had to be accountable.”
How Julie’s diet has changed
“We have completely changed our lives and learnt a whole new way of cooking.”
- Takeaways: “We choose healthy options like stir-fries instead of fish and chips.”
- Sweets: Formerly a keen baker, Julie still makes sweet treats but gives most of her creations away immediately. On social occasions she has only a sliver of dessert “if I really feel like it”, and gives leftovers to people to take home.
- Veges and fruit: She spends a lot of her supermarket budget on veges and fruit.
- Portion control: She’s reduced her portion sizes.
Article sources and references
- Aune D et al. 2015. Physical activity and the risk of type 2 diabetes: a systematic review and dose-response meta-analysis. European Journal of Epidemiology 30:529–42https://www.google.com/search?q=Aune+D+et+al.+2015.+Physical+activity+and+the+risk+of+type+2+diabetes%3A+a+systematic+review+and+dose-response+meta-analysis.+European+Journal+of+Epidemiology+30%3A529%E2%80%9342&rlz=1C1GCEU_enNZ820NZ820&oq=Aune+D+et+al.+2015.+Physical+activity+and+the+risk+of+type+2+diabetes%3A+a+systematic+review+and+dose-response+meta-analysis.+European+Journal+of+Epidemiology+30%3A529%E2%80%9342&aqs=chrome..69i57.439j0j9&sourceid=chrome&ie=UTF-8
- Baker IDI Heart & Diabetes Institute. Understanding diabetes. www.bakeridi.edu.au Accessed February 2016https://baker.edu.au/
- Coppell KJ et al. 2013. Prevalence of diagnosed and undiagnosed diabetes and prediabetes in New Zealand: findings from the 2008/09 Adult Nutrition Survey. New Zealand Medical Journal 126(1370)https://www.nzma.org.nz/journal/read-the-journal/all-issues/2010-2019/2013/vol-126-no-1370/article-coppell
- Diabetes New Zealand. www.diabetes.org.nz Accessed February 2016https://www.diabetes.org.nz/
- Feinman et al. 2015. Dietary carbohydrate restriction as the first approach in diabetes management: Critical review and evidence base. Nutrition 31:1–13https://www.ncbi.nlm.nih.gov/pubmed/25287761
- Gunasekaran U & Gannon M. 2011. Type 2 diabetes and the aging pancreatic beta cell. Aging 3:565-75https://www.ncbi.nlm.nih.gov/pubmed/21765202
- Hamman RF et al. 2006. Effect of weight loss with lifestyle intervention on risk of diabetes. Diabetes Care 29:2102–7https://www.ncbi.nlm.nih.gov/pubmed/16936160
- Mann J. 2016. Personal communication 24 February 2016
- Screening, diagnosis and management of gestational diabetes in New Zealand: A clinical practice guideline. Wellington: Ministry of Healthhttps://www.health.govt.nz/publication/screening-diagnosis-and-management-gestational-diabetes-new-zealand-clinical-practice-guideline
- Ministry of Health. 2015. Living well with diabetes: A plan for people at high risk of or living with diabetes 2015–2020. Wellington: Ministry of Healthhttps://www.health.govt.nz/system/files/documents/publications/living-well-with-diabetes-oct15.pdf
- New Zealand Society for the Study of Diabetes. www.nzssd.org.nz Accessed February 2016https://www.nzssd.org.nz/
- Tay et al. 2015. Comparison of low- and high-carbohydrate diets for type 2 diabetes management: a randomized trial. American Journal of Clinical Nutrition. 102:780–90https://www.ncbi.nlm.nih.gov/pubmed/26224300
- The Diabetes Prevention Program Research Group. 2006. The Influence of age on the effects of lifestyle modification and metformin in prevention of diabetes. Journals of Gerontology Series A. Biological Sciences 61:1075–81https://www.ncbi.nlm.nih.gov/pubmed/17077202
- Tucker R. 2014. Keeping exercise short and hard: what’s involved and is it worth it? The Pharmaceutical Journal 292:442https://www.pharmaceutical-journal.com/publications/the-pharmaceutical-journal?firstPass=false