The diabetes diet

Menu items for patients with type 1 and type 2 include fibre-rich fruits and canola oils. 

In 2013, there were about 1,160,000 people living with diabetes in Australia. Of these, about 15 per cent had type 1 diabetes, and 80 per cent had type 2.

Type 1 is a disease of disordered immune function involving destruction of the beta cells in the pancreas that secrete insulin in people who are genetically susceptible. As a consequence, people with type 1 diabetes do not produce any endogenous insulin and are dependent on exogenous insulin for life. To achieve and maintain optimal glycemia and overall health, medical nutrition therapy and regular physical activity are essential.

Type 2 diabetes, on the other hand, is one of the most common chronic diseases in Australia, with rates increasing in parallel with the growth in rates of excessive weight and obesity.

Type 2 is most common in those aged 45 years or older, and reaches peak prevalence in the 60- to 70-year-old age group; however, due to increased rates of childhood obesity, children and adolescents are also now being diagnosed with this disease. Type 2 diabetes is primarily a metabolic ailment, characterised by insulin resistance and relative insulin deficiency. It is strongly associated with obesity in genetically susceptible individuals. Management includes medical nutrition therapy, regular physical activity and/or oral hypoglycemic agents with the aim of increasing insulin sensitivity and/or increasing insulin secretion, although eventually many people also require exogenous insulin.

Whilst diabetes is characterised by abnormal glucose metabolism, abnormalities in blood lipids and blood pressure are also common manifestations of the condition. Consequently, people with diabetes are at an increased risk of developing a range of micro- and macro-vascular complications, including nephropathy, neuropathy, retinopathy, heart disease, stroke and peripheral vascular disease.

Goals of nutritional management

Medical nutrition therapy (MNT) plays an important role in the prevention of type 2 diabetes, in managing existing diabetes (type 1, type 2 and gestational diabetes) and in preventing or reducing the progression of diabetes-related complications.

Whilst there are differences in the way type 1 and type 2 are managed, the main goals of nutritional management are essentially the same. These are:

• to achieve and maintain blood glucose levels in the normal range, or as close to the normal range, as is safely possible
• to achieve and maintain blood pressure and a blood lipid profile that reduces the risk for cardiovascular disease
• to prevent or reduce the progression of diabetes complications
• to achieve and maintain a healthy body weight
• to consider personal and cultural food preferences and an individual’s readiness and willingness to change
• to maintain the enjoyment of eating by limiting food choices only when indicated by scientific evidence.

Dietary guidelines and recommendations

General healthy eating guidelines for people with diabetes are similar to those of the general population, and are consistent with The Australian Dietary Guidelines. The Australian Guide to Healthy Eating is the food selection manual that accompanies the guidelines, and visually represents the proportions of the five food groups recommended for consumption each day. The Guidelines and accompanying resources can be found at eatforhealth.gov.au

Individuals with diabetes do still need individualised dietary advice, preferably from an accredited practising dietitian with expertise in diabetes management.  This is particularly important for:

• individuals with type 1 diabetes
• those with type 2 diabetes who are taking oral or injectable hypoglycemic agents or insulin
• women with gestational diabetes
• Individuals with co-morbidities that require further nutritional advice specific to that condition (for example, renal, cardiovascular or gastrointestinal conditions, and allergies etc).

These individuals will all need more specific instruction, particularly around carbohydrate intake.

Here are some more specific dietary recommendations for people with diabetes:

• Carbohydrates – eat carbohydrate-rich foods at each main meal, with a similar intake from day to day, and/or matched with an insulin dose for those taking insulin. Carbohydrate should come mainly from fibre-rich fruits, vegetables, whole grains and legumes, as well as lower-fat milk and yoghurt. Choose mostly carbohydrate-rich foods with a low glycemic index (GI), including dense wholegrain breads, oats, barley, legumes, corn, cracked wheat, quinoa, pasta, noodles, most fruits, milk and yoghurt.
• Saturated fats – limit the intake of saturated fat and avoid trans fats by choosing lean meats and lower-fat dairy products, and limiting the intake of fast foods and manufactured biscuits, chips, cakes and pastries.
• Unsaturated fats – consume a moderate amount of unsaturated fats from olive and canola oils, fish, nuts, seeds and avocados.
• Protein – high-protein diets are not recommended due to possible negative effects on kidney function and a lack of evidence for long-term benefits.
• Alcohol – consumption should be limited to no more than two standard drinks a day, with at least two alcohol-free days each week. Alcohol may be contra-indicated in some individuals due to interactions with medication or risk of hypoglycemia.

How nurses can help

Good nutrition plays an important part in the management of diabetes and should be encouraged by all members of the healthcare team including nurses.

In addition, nurses can provide information and education on the importance of good nutrition and give general dietary advice based on the Australian Dietary Guidelines, which are relevant to most people with diabetes.

All individuals with diabetes should be referred to an accredited practising dietitian for individualised dietary assessment and advice whenever possible. A dietitian can help people with diabetes achieve and maintain a healthy weight, and better understand how food affects management of their disease. A dietitian  can assist in making changes to improve blood glucose levels, lipids (cholesterol and triglycerides) and blood pressure.

Dr Alan Barclay and Dr Kate Marsh are the co-convenors of DAA’s diabetes interest group.

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