Diabetes: The latest scientific findings

Diabetes is our nation's fastest growing chronic disease, and it is affecting teenagers and children as well.

Around 270,000 New Zealanders have type 2 diabetes and although it's most commonly diagnosed in people over 30 years old, increasing numbers of teenagers and children are developing the disease. A few years ago, type 2 diabetes was virtually unknown in teenagers, but it's now estimated around 500 young people aged between 10 and 18 years old have the disease. Around 15,000 New Zealanders have type 1 diabetes, and although the numbers here for gestational diabetes are not known, in Australia it's estimated five per cent of women will develop it.

No one has yet discovered the answers that will lead to a cure, but the scientific community has made substantial progress. Here is an update of the latest medical advice.

Try to maintain a healthy weight

Carrying extra weight makes it more difficult for your body's insulin to do its job. Losing weight reduces blood glucose levels, blood pressure and blood fats, and reduces your risk of heart disease.

Eat a healthy diet

Your diet should be aimed at controlling your weight, glucose levels, blood fats and blood pressure.

• Keep your intake of saturated fat low and avoid trans fats by choosing lean meats and low-fat dairy products, and by limiting the intake of fast foods and manufactured biscuits, chips, cakes and pastries.
• Maintain a regular intake of carbohydrate foods spread over the day to avoid large fluctuations in blood glucose levels. If you take insulin, the amount of carbohydrate you eat at each meal needs to be matched to your insulin dose. Carbohydrate should come mainly from fibre-rich fruits, vegetables, whole grains and legumes, as well as low-fat dairy products.
• Choose mostly low-GI carbohydrate foods including heavy whole grain breads, oats, barley, legumes, corn, cracked wheat, quinoa, pasta, noodles, many fruits, and dairy products such as milk and yoghurt.
• Avoid a high-protein diet (more than 20 per cent of energy from protein). They are not recommended due to possible negative effects on kidney function and a lack of evidence for long-term benefits.
• If you drink alcohol, stick to one standard drink per day if you are female and two if you are male.

Exercise regularly

• Do some form of moderate-intensity aerobic exercise such as walking, cycling or swimming for at least 150 minutes each week (ie. 30 minutes, five days of the week).
• Include resistance training three times per week. This can help control blood glucose levels and blood pressure, and improve blood cholesterol levels. Consult your doctor first before participating in resistance training exercises – some complications related to diabetes can mean certain exercises may not be appropriate.

Don't smoke

If you smoke and you're struggling to give up the habit, there are a number of options available to help you, including counselling, patches and medications. Speak to your doctor or call Quitline on 0800 778 778 (or visit www.quit.org.nz).

Have regular tests

These tests are to monitor diabetes control and detect any complications:

HbA1c (a measure of your average glucose levels over the past two to three months): Have this test every three to six months. Generally, people with diabetes should aim for an HbA1c below 53mmol/mol (or seven per cent), but discuss this with your doctor.

Blood fats (including cholesterol and triglyceride levels): Have this test at least yearly, or more often if you are outside the target range. If LDL ('bad') cholesterol levels are greater than 2mmol/L and/or triglyceride levels are greater than 1.7mmol/L following lifestyle changes, medication may be needed.

Blood pressure: Have this test every time you visit your doctor. A blood pressure reading of greater than 130/80 (or 125/75 if you have proteinuria – protein in the urine) indicates the need for medication.

Kidney function: Have this test annually. A simple urine test looks for very small amounts of protein leaking into the urine – a sign that the kidneys are not working properly.

Eye examination: Have this test soon after a type 2 diabetes diagnosis, and within five years of diagnosis for type 1 diabetes, then every one to two years, or more frequently if problems are found. Speak to your optometrist or ophthalmologist.

Feet examination: Have this test once per year, to check for any circulation or nerve problems which could contribute to ulcers. If problems are detected, regular check-ups with a podiatrist are commended. It is also important to check your feet daily at home.

Is lowering blood glucose levels dangerous?

Long-standing medical knowledge has dictated that aiming for normal blood glucose levels (BGLs) lowers the risk of death from cardiovascular disease. But a recent US study of more than 10,000 people with type 2 diabetes found lowering BGLs (with a HbA1c target of 42mmol/mol or six per cent) may actually increase the risk of death. So what's the truth?

No one's sure, but experts speculate participants may have lowered their BGLs too quickly – and that these results may only be specific to the US population (indeed, a similar Australian study of 11,140 people found that lowering BGLs slowly [to HbA1c levels of around 48mmol/mol (or 6.5 per cent] actually lowered the risk of death). It's best to consult your GP about your specific, personal needs.