physicians towards trying to achieve the necessary dietary and lifestyle changes through educating individuals to a level such that they can make their own informed choices regarding their management.
However, a greater under- standing of the factors that influence the uptake of lifestyle advice is required if more effective dietary management for people with diabetes is to be achieved in the future.
Despite the availability of several different classes of oral hypoglycaemic agents for the management of Type 2 diabetes, dietary and lifestyle manage- ment remains crucial for the optimal effectiveness of these drugs.
It might at first appear strange that this book contains only a summary chapter dealing with Type 2 diabetes.
This is because the lifestyle messages for the management of people with Type 2 diabetes are covered in other chapters throughout the book, including those addressing guidelines, exercise, counselling and obesity.
Lifestyle and dietary changes for people with Type 2 diabetes are required, not only for glycaemic control but also for reducing important cardiovascular risk factors.
The aim of this book is to provide a practical guide for the dietary management of diabetes based on basic physiological principles as well as nutritional and clinical evidence.
We hope this book will aid health professionals to provide their patients with informed evidence-based advice in a way most likely to achieve the meaningful nutritional changes that will improve their quality of life.
Acknowledgement We wish to thank Dr Louise Goff for her help in proof reading this book.
Nutritional Recommendations in Diabetes Management NORMA MCGOUGH BSc SRD Aylesbury, Buckinghamshire, UK
INTRODUCTION
The first position statement on diet in diabetes care was made by Diabetes UK, formerly the British Diabetic Association, 20 years ago (1).
The recommenda- tions liberalised the diet for people with diabetes.
Previous advice had focused specifically on carbohydrate intake and sugar restriction.
The new recommen- dations promote a diet in line with healthy eating recommendations for the general population and compatible with dietary advice for people at high cardiovascular risk.
Further review, 10 years later, resulted in an update that re-enforced the high-carbohydrate, low-fat diet (2).
These recommendations have now been superseded by recommendations from other parts of the world including Europe (3) and America (4).
A more recent technical review of the nutritional management of patients with diabetes also helps to put a clear perspective on dietary education in diabetes care (5).
CURRENT POSITION
Recommendations will change in time as new data becomes available and consensus and views on emphasis differ. Any recommendations require careful interpretation and communication for the maximum benefit of those individuals with diabetes.
Nutritional Management of Diabetes Mellitus. Edited by G. Frost, A. Dornhorst and R. Moses & 2003 John Wiley & Sons, Ltd. ISBN 0 471 49751 7
2 NUTRITIONAL MANAGEMENT OF DIABETES MELLITUS
The biggest change in emphasis of the recommendations currently in use compared to previous recommendations focuses on a greater flexibility between the proportion of energy from carbohydrate and fat, with promotion of the use of monounsaturated fat.
Diets rich in monounsaturated fat reduce total and low-density lipoprotein cholesterol without adverse effects on high- density lipoprotein cholesterol or triglyceride levels (6).
It is necessary to restrict the total fat content of the diet where obesity is an issue and calorie intake needs to be limited.
Otherwise, a range of carbohydrate (45, 60%) and fat (25, 35%) intakes is compatible with good diabetes control provided that low glycaemic index carbohydrates and foods high in monounsaturated fat are promoted.
Other significant changes in the recommendations include: .
There is less emphasis on the benefits of cereal fibre other than for gastrointestinal health and its satiety value. .
The precise effects of antioxidant nutrients with regard to being potential cardio-protective factors is still uncertain and so clear guidance is not possible in the light of the evidence available. .
In most European countries, the average intake of protein is in excess of the recommended intake and for those people with Type 1 diabetes, especially in those with hypertension, intakes of protein should not exceed 10, 20% total energy because of the increased risk of nephropathy. .
The benefits of physical activity for people with diabetes are becoming increasingly evident.
Regular, moderate intensity exercise is associated with a reduced risk of developing Type 2 diabetes in men, women and individuals who are overweight (7,8).
Exercise can produce a reduction in plasma triglycerides, increases HDL and can also aid weight loss (9).
The overall impact of exercise on blood pressure is also beneficial (10).
AIMS OF THE NUTRITIONAL RECOMMENDATIONS
The goals of dietary advice are to achieve and maintain good health and quality of life, with avoidance and management of short-term symptoms, including hypoglycaemia and freedom from the long-term complications of the disease, for as long as possible. Evidence available from America from the Diabetes Control and Complications Trial in Type 1 diabetes (11) and also from the United Kingdom Prospective Diabetes Study in Type 2 diabetes (12) suggests that normalisation of metabolic markers like blood glucose levels and management of blood pressure constitute key aims. There needs to be a balance between the attainment of objectives of care and the demands that they may impose on the individual person with diabetes.
NUTRITIONAL RECOMMENDATIONS IN DIABETES MANAGEMENT 3
The recommendations should be adapted to an individual’s lifestyle, culture and socio-economic status.
Personalised targets, based on the recommendations, need to be negotiated, clearly defined and communicated.
There should be regular review and on-going dietary education.
The Practice Guidelines for Medical Nutrition Therapy developed in the USA for Type 1 diabetes have been shown to result in significant improvements in glycaemic control, and require more frequent and longer contacts between dietitians and patients (13).
Patients from UKPDS, in centres with a greater availability of dietetic advice, lost more weight than those with less advice and also tended to have a greater decrease in plasma glucose (14), thus showing the need for more intensive care of diabetic patients.
APPLICATION OF THE NUTRITIONAL GUIDELINES
Since diabetes is a life-long disease that affects all groups of the population, irrespective of age, culture or socio-economic status, it is vitally important to identify the most appropriate approach to the application of the nutritional guidelines, from the outset.
Dietetic intervention requires an appropriate level of knowledge, experience and skill if dietary habits and eating behaviour are to be adjusted, effectively (15).
The Clinical Standards Advisory Group (CSAG) in the UK recommended that all newly diagnosed patients should be offered a dietetic consultation within four weeks of diagnosis and that non-crisis dietetic review should be available, annually, to all people with diabetes (16).
UKPDS showed that the first three months were vitally important in determining response to dietary intervention (14).
Currently in the UK one current issue of dietary management in diabetes care is the under-provision of dietetic services in diabetes care (17).
PROVISION OF SERVICES IN DIABETES CARE
In 1997, Diabetes UK, formerly the British Diabetic Association, investigated the provision of dietetic services in diabetes care.
They carried out a postal survey to dietitians in the UK to assess level of provision and current practices including application of nutritional guidelines, audit and evaluation.
The survey showed that 85% of dietitians worked in situations where dietetic provision was less than the current recommendation of 22.5 hours per 100 000 of the population, made by Diabetes UK, in 1999 (18).
One of the outcomes of this situation is that people with diabetes may not receive dietary education from a State Registered Dietitian.
Dietary education may be part of an education package offered in general practice by the practice nurse.
The evolution of the nutritional guidelines for people with diabetes to a status
4 NUTRITIONAL MANAGEMENT OF DIABETES MELLITUS
which is in line with healthy eating recommendations for the general population may have ‘de-mystified’ the diet in diabetes care to the extent that it was perceived as being a package that could be relayed without the expertise of a dietitian.
There is a need for a consistent approach from health care professionals.
Co- ordination of training of all health care professionals involved in diabetes education on nutrition and diabetes as well as overall management of dietary education in diabetes care is essential to ensure a high-quality service to all people with diabetes.
Continuing professional development is essential to update knowledge and skills.
THE ROLE OF THE DIETITIAN IN DIABETES CARE
Ideally, it is the role of the dietitian to provide the dietetic intervention.
A vital part of the dietetic consultation is the assessment of readiness to change eating behaviour (19).
Exploration of barriers to change and awareness of psycho- social issues form part of the dietary consultation process.
In the short term, food intake needs to be regulated and balanced against medication, in order to optimise blood glucose control.
This also includes assessment of whether current medication matches the meal pattern and therefore whether it is appropriate, as well as the management and prevention of hypoglycaemia and hyperglycaemia.
Long-term dietary control can offer protection against cardiovascular disease with weight management and modification of other lifestyle factors being essential.
Dietary counselling should be innovative and specific to the requirements of the individual, rather than being rigid, prescriptive and restricted to a particular system of teaching, as may be the case when knowledge, experience and skills in diet therapy are limited.
AUDIT AND EVALUATION
Since the 1970s, the success or failure of diet in diabetes care has been based on compliance (20).
The most important consideration being whether or not a patient was deemed to have modified their dietary intake and achieved a particular dietary prescription.
Evaluation needs to consider the impact of diet on clinical outcomes like body weight, lipid levels and HbA1C.
Application of the nutritional guidelines is not about achieving the gold standard but about the modification of an individual’s dietary intake to shift the balance in the direction of the gold standard and at the same time, maximise health benefits and quality of life for that individual.
Findings of the Diabetes UK survey in 1997 show that a quantitative method of dietary prescription is no longer applied in practice.
The survey also shows
NUTRITIONAL RECOMMENDATIONS IN DIABETES MANAGEMENT 5
that most dietitians reported, at the time, following the 1992 nutritional guidelines. The nutritional recommendations in the UK are under review and the more up-to-date guidelines from Europe and America should be applied until updated recommendations are published in the UK.