What is diabetes?
Our bodies obtain energy from glucose in the bloodstream. Insulin is a hormone that helps get glucose from the bloodstream into cells where it's needed for energy and storage (in the form of glycogen), and also plays a role in protein and fat metabolism. People with some form of diabetes – properly known as diabetes mellitus – have abnormal insulin function, putting them at risk of high blood sugar levels.
Type 1 diabetes
Type 1 diabetes is an autoimmune condition where the body destroys its own insulin-producing cells in the pancreas. People tend to get it in childhood or adolescence, although some get it as adults. People with type 1 diabetes need to take insulin by injection or an insulin pump.
Type 2 diabetes
Type 2 diabetes tends to come on in older adulthood and is due to reduced production of insulin or reduced effectiveness of insulin (called insulin resistance). While it typically starts in people aged over 40 – and affects about 15% of over-65s – the disease is becoming more common in younger adults and adolescents, likely due to increased obesity in this age group. In its early stages, type 2 diabetes can be successfully managed with lifestyle modifications (diet, exercise and weight loss), though some people will need medication, and perhaps insulin.
Gestational diabetes is another common form of diabetes, specific to pregnant women. Although it often resolves after birth, women who've had gestational diabetes are at higher risk of type 2 diabetes later in life. It affects about 5-10% of pregnant women, and those with a family history of type 2 diabetes are at increased risk.
Pre-diabetes is the term for when blood glucose levels are high but not high enough to qualify for diabetes. This is characterised by impaired glucose tolerance or impaired fasting glucose. Although there's a high likelihood people with pre-diabetes will go on to develop full-blown type 2 diabetes, lifestyle changes at this point – including modest weight loss, reducing saturated fat intake and increasing physical activity – can prevent it in more than half of all cases.
Around five percent of Australians have been diagnosed with diabetes – about 10% of these have type 1, while the overwhelming majority live with type 2. It's also estimated that almost one in six adults (over 25) has pre-diabetes.
Symptoms of diabetes
Symptoms of diabetes include:
- frequent need to urinate
- slow healing of infections
- blurred vision.
However, many people have no symptoms, and it may be years before the diabetes is diagnosed. By that stage the disease has taken hold and vascular damage may have already occurred.
The damage caused by diabetes
High levels of glucose in the blood lead to blood vessel damage, which in turn can lead to the following main complications of diabetes:
- Nerve damage and poor circulation in the feet, which can lead to ulcers and infections, ultimately necessitating amputation
- Eye disease (diabetic retinopathy, glaucoma and cataracts), which can lead to blindness
- Kidney disease, which may require dialysis or kidney transplant
- Cardiovascular disease (including hypertension, stroke, coronary heart disease and angina) which is the main cause of death among diabetics.
How a person manages their diabetes depends on their type of diabetes, but methods include:
- monitoring blood glucose levels
- insulin replacement (via injections or a pump)
- maintaining a healthy diet and weight
Monitoring blood sugar levels
Even if sugar levels may be fine in general, short periods of high blood sugar can still cause damage, which is why it's very important for people with diabetes to constantly monitor and control blood sugar levels. Conversely, long periods of good control have a protective effect against future periods of light control. Unfortunately, only about half of diabetics have adequate control over blood sugar levels.
Who's at risk of diabetes?
The risk of diabetes increases after age 40, is more prevalent among men than women, and is higher among certain ethnic groups – for example, Indigenous Australians, Maori and Pacific Island peoples, as well as people born in India, certain Asian countries, the Middle East and north Africa. While genetics are involved, lifestyle factors such as diet and exercise, and especially body weight, can determine how or if these genetic tendencies are played out.
Unhealthy lifestyles may account for the increase in type 2 diabetes, but the cause of an increase in type 1 diabetes is not so clear cut. Viruses have been blamed, but other theories and observations are currently being researched, such as the following:
- Babies born by Caesarean section are 20% more likely to develop type 1 diabetes than vaginally born babies. Research has shown that the gut bacteria of caesarean babies is very different to that of vaginally born babies, and this has implications for immunity (type-1 diabetes is an autoimmune disease).
- People living in high-latitude areas (such as Scandinavia, parts of Canada and southern Australia) are more susceptible to type 1 diabetes and other autoimmune diseases. This could be purely genetically-based, but it's also been linked with vitamin D deficiency, which impacts immunity.
- Endocrine-disrupting chemicals (EDCs) such as polychlorinated biphenyls, bisphenol A, phthalates and dioxin affect hormonal systems of the body. Insulin and vitamin D are hormones. EDCs are found at high levels in the food chain and environment, and at higher levels in people from developed countries – as is type 1 diabetes.
Testing for diabetes
- The Department of Health risk assessment tool and Diabetes Australia's risk calculator estimate your future likelihood of diabetes depending upon age, waist circumference (you'll need a tape measure), gender, ethnicity and place of birth, lifestyle and previous instances of testing high on blood sugar (during pregnancy, for example). People with elevated risk should consult their doctor and possibly have further testing.
- Self-test blood glucose kits are also available, and may seem more convenient than going to the doctor for a blood test. However, although they can reassure you that you don't have high blood glucose levels at the time of the test, a fasting glucose test doesn't tell you how well your body responds to high levels of glucose (after a meal, for example) nor provide a broader picture of short to long-term future risk.
Tips for preventing diabetes
Although you can't do anything about your age, chromosomes or ethnicity, there are other lifestyle-related risk factors that you can manage. Here are our top 10 tips to leading a healthy lifestyle and reducing your risk of diabetes:
- Exercise regularly and avoid long periods of sitting around.
- Keep a healthy body weight.
- Get your two and five servings of fruit and vegetables every day.
- Fibre is your friend – eat plenty of it.
- Reduce saturated fats in your diet.
- Drive through the drive-thru – don't stop! Also limit processed foods.
- Limit alcohol.
- Don't smoke.
- Reduce your salt intake.
- Check your diabetes risk with one of the tools mentioned above in Testing for diabetes.
Independent medical research facility, Baker Heart and Diabetes Institute, advocates for legislative and societal changes to facilitate healthy behavioural choices. This may involve changes to local town planning, the way food is marketed and even occupational health and safety regulations to reduce sedentary work practices.
The psychological impact
Diabetes is not just a physical disease – it takes a huge emotional toll as well. Feelings of helplessness and despair are all too common, according to Katrina Thornley, a psychologist who counsels people with diabetes, and a diabetic herself.
"Often people with diabetes are so overwhelmed and despondent they are simply emotionally unable to adopt the measures recommended by their doctor to manage their diabetes successfully," she says.
Counselling can help people deal with stress, anxiety and depression associated with diabetes, as well as 'diabetes burnout', which occurs when people get fed up with having to constantly monitor blood sugar, count carbohydrates, exercise as prescribed and manage insulin and/or other medication.
Counselling can also be useful for family members of diabetics who find themselves caught up in their loved ones' struggles with diabetes.
People with diabetes are entitled to Medicare-funded sessions with registered psychologists, so ask your doctor for a referral. The Australian Psychological Society has a searchable database for psychologists with special interests, such as health-related problems or chronic disease management.
What causes diabetes?
While increasing levels of obesity are blamed for the increase in rate of type-2 diabetes, not everyone who has diabetes is obese, and not everyone who is obese has diabetes. This has led to thinking that obesity isn't responsible for causing diabetes, but rather it's down to other factors common to both.
Obesity, diabetes and cardiovascular disease (including hypertension, dyslipidaemia and atherosclerosis) have been linked with a chronic low-grade systemic inflammation sometimes called metaflammation (meaning a metabolic inflammation), which has various physiological effects, including changes to glucose and fat metabolism that lead to insulin resistance and weight gain.
There is emerging evidence in animals and humans that some nutrients, such as saturated and trans-fats, excessive salt and sugar have an inflammatory effect, as do high glycaemic-index foods, such as white rice and potatoes. Conversely, foods including fruit and vegetables, fish, nuts, cocoa and tea have demonstrated have an anti-inflammatory effect. Excessive alcohol appears to cause metaflammation, while moderate intake is protective.
This ties in with long-term studies that have found a higher risk of developing diabetes among people with diets high in red and/or processed meats, low-fibre refined breads and cereals, fried potatoes and sugar-sweetened drinks, and low in fruit, vegetables and whole grains.
Diabetes Australia is the national is the national body for people affected by all types of diabetes and those at risk.
Baker IDI Heart and Diabetes Institute is an independent medical research facility which specialises in diagnosis, prevention and treatment of diabetes and cardiovascular disease.
Better Health Channel has comprehensive information on diabetes.
Diabetes and the Environment is a 'clearinghouse' of information about causes of diabetes, in particular environmental causes of type-1 diabetes. Other types of diabetes and other causes are also covered. The site's author – an environmental scientist with type-1 diabetes – sources and references the latest research in this area, and presents it in a clear, readable and entertaining manner.
- Impaired fasting glucose: Blood glucose levels that are consistently high (though not high enough to qualify for diabetes), measured about 12 hours after eating. This indicates pre-diabetes.
- Impaired glucose tolerance: Determined by a glucose tolerance test, where blood glucose levels are measured before and after 75g of glucose is consumed. Glucose levels that are high (but not high enough to qualify for diabetes) at two hours indicate impaired glucose tolerance.
- Insulin resistance: When cells become less sensitive to the effects of insulin as it helps transport glucose from the blood stream into cells. More and more insulin is produced by the pancreas in an attempt to deal with the circulating glucose. High levels of insulin measured in the blood indicate insulin resistance.
- The metabolic syndrome: A cluster of risk factors for cardiovascular disease: diabetes or raised fasting plasma glucose, abdominal obesity, high cholesterol and high blood pressure.