Managing type 2 diabetes
Diabetes mellitus describes a group of metabolic disorders which are characterised by high blood glucose concentrations and disordered insulin metabolism. It is often characterised into type 1, type 2 or gestational diabetes.
Type 1 diabetes is an autoimmune disease where the body's own immune system destroys the insulin-producing beta cells in the pancreas. Without the production of insulin, cells cannot take up circulating blood glucose, disrupting the body's energy metabolism. Current thinking suggests the cause of type 1 diabetes involves an interaction between environmental factors and genetic predisposition. Although type 1 diabetes can occur at any age, it is most commonly diagnosed in children and adolescents and requires lifelong management with insulin.
Type 2 diabetes is the most prevalent form of diabetes and can often be asymptomatic. It is also largely preventable through diet and exercise. The primary defect in type 2 diabetes is insulin resistance where muscle, adipose and liver cells become resistant to the action of insulin. To compensate, the pancreas secretes greater amounts of the hormone. Over time the pancreas slowly loses its ability to compensate and hyperglycaemia follows. Certain ethnicities, being overweight or obese, genetics, smoking and high blood pressure all increase a person's risk of developing type 2 diabetes. Insulin, medications and lifestyle interventions can all be used in the management of this condition.
Gestational diabetes involves high blood glucose levels appearing during pregnancy amongst women who have no history of diabetes. It can cause complications during pregnancy but also increases a mothers risk of developing type 2 diabetes later in life.
The prevalence of diabetes in the Australian adult population is around 1 in 20 or 5.4% based on self-reported measures (2011-12 Australian Health Survey). Diabetes was found to be more common in males than females and increased rapidly with age up to age 75. The rates of diabetes increased the further populations moved away from major city centres.
Type 2 diabetes is considered the fastest growing chronic condition, but significantly it can be prevented. Type 2 diabetes accounts for 85% of diabetes cases in Australia and is the most common form of diabetes in New Zealand where its incidence is continuing to rise and its prevalence is reported as over 200,000 persons.
For lifestyle management of Type 2 diabetes, diabetes associations generally recommend a healthy balanced diet, regular physical activity, and regular monitoring of blood glucose levels. Nutritional recommendations follow the general guidelines for a healthy population. To help manage diabetes, meals should be spread regularly throughout the day, and be low in saturated fat. Individual meal plans can be particularly helpful for tailored dietary advice. However, there is no longer a need for people with diabetes to focus on a sugar free diet as complete avoidance of sugar is now known to be unnecessary and the idea was not found to be based on scientific evidence.
Sugar itself is not proven to cause diabetes. Diabetes is caused by inadequate production or a lack of the hormone insulin. Insulin plays a key role in controlling the level of glucose in the blood and monitoring carbohydrate intake helps achieve glycemic control. While sugar is included in this equation, of note, sucrose has a medium Glycemic Index (GI) (~60-65) and so causes no greater swing in blood glucose than many other starchy carbohydrates. Sugars can therefore be included in moderation as part of a healthy meal plan for people with diabetes.
A low GI diet has a specific benefit in the management of diabetes. Scientific evidence points to improved glycemic control when compared to a high GI diet, improved insulin sensitivity and reduce insulin resistance, reduced risk of vascular disease, and greater weight loss when compared to other healthy diets. A low GI diet may also be protective against Type 2 diabetes.
People with diabetes should be aware of the factors that can influence their blood glucose control, as the glycemic response to foods can vary by degree of severity of diabetes. The GI of a particular food or meal can also be affected by the protein, fat and dietary fibre content, as well as the form in which foods are consumed (hot, cold or cooked).
Type 2 diabetes is strongly associated with overweight and obesity, low physical activity and genetics or family history. Therefore as well as having a balanced diet, engaging in regular activity is important to try and maintain a healthy body weight. Benefits include lower blood glucose levels and improved insulin sensitivity. Physical activity can also help to lower blood pressure, blood triglyceride levels and overall risk of cardiovascular disease. People with diabetes are advised to have at least 30 minutes of moderate physical activity on most days of the week.
Type 2 diabetes has a natural progression towards use of other management strategies, such as tablets and insulin to help control blood glucose. The overall focus is on keeping blood glucose levels within the target range. If this is maintained, the risk of short and long term complications is reduced. Monitoring blood glucose levels regularly helps identify whether the course of treatment is working or needs to be adjusted.
Diabetes New Zealand. The facts about sugar and diabetes http://www.diabetes.org.nz/food_and_nutrition/healthy_food_choices__and__tips/food/sugar;
Diabetes Australia. Diabetes and food- what should I eat? http://www.diabetesaustralia.com.au/en/NDSS-Content/Living-with-Diabetes/Eating-Well/What-Should-I-Eat/#Sugar