Aims Of Nutritional Management Of Childhood And Adolescent Type Diabetes

• Provide appropriate energy and nutrients for optimal growth, development and health

• Achieve and maintain ideal body weight

• Achieve and maintain optimal glycaemic control on an individual basis, balancing food intake with metabolic requirements, physical activity and insulin treatment

• Prevent hypo- and/or hyperglycaemia due to insulin, illness and exercise

• Reduce the risk of long-term micro- and macrovascular complications

• Preserve social and psychological well-being

'PROVIDE APPROPRIATE ENERGY AND NUTRIENTS FOR OPTIMAL GROWTH, DEVELOPMENT AND HEALTH'

Energy and Nutrients

Children with well-controlled diabetes have similar average energy intakes and nutrient requirements as their peers. As individual daily intakes and requirements vary due to growth, maturity and exercise, nutritional requirements need to be reviewed regularly with the use of height/weight growth charts. All advice should aim to achieve ideal body weight while meeting the recommendations specified in the Dietary Reference Values (DRVs) for the United Kingdom (18).

Growth in Relation to Energy Balance and Metabolic Control

Children's growth rate is continually changing but the phases of particularly rapid growth are in infancy and puberty. Health care professionals need to be made aware that for optimal growth between 6 and 12 years children with diabetes must double their energy intake. Total energy and protein intake needs to increase at this time. However after these rapid phases of growth, or cessation of growth, failure to reduce energy intake will lead to obesity. Adjusting dietary intake during these continually changing metabolic demands is central to the dietary management of childhood diabetes and requires ongoing regular review by a trained paediatric dietitian.

Growth potential may not be fulfilled when glycaemic control is poor, as glycosuria can cause significant urinary energy loss while insufficient insulin treatment can cause inadequate anabolism. Energy requirements, carbohydrate intake and insulin doses increase throughout childhood and rise markedly during puberty. Adolescents and parents need to be reassured that increasing carbohydrate intake is both normal and essential at this time and will not jeopardise overall metabolic control. Parents often compensate for the increased appetite of puberty by increasing inappropriate non-carbohydrate foods that are high in fat and/or protein. In boys, particularly, appetite can increase dramatically during the pubertal growth spurt and parents and adolescents need to appreciate that any increase in food intake should be accompanied by an increase in insulin dose.

Protein

The normal protein requirements are:

• 0.8 g/kg in later adolescence towards adulthood

Children in Western countries however find it easy to exceed these requirements, obtaining 15-20% of their total energy intake as protein (19), while a safer level is nearer 10-15% (1,19,20).

Proteinuria (albumin excretion rate >300 mg/min) is uncommon before puberty but microalbuminuria may start or accelerate during puberty. Sustained high protein loads may be detrimental to renal function, especially if there is renal disease (19,21), and this is particularly important in adolescents. However, any protein restriction should not be allowed to compromise normal growth and maturation and it is essential under these circumstances that careful nutritional and metabolic assessment is carried out.

Animal sources of protein are associated with higher fat intakes, especially saturated fat and therefore should not be consumed in large amounts. Vegetable protein is lower in fat, higher in fibre and complex carbohydrates and should therefore be encouraged. Until further evidence is available it is not necessary to decrease protein intake below that recommended for non-diabetic children and in the UK the national standard DRVs for Food Energy and Nutrients for the United Kingdom should be adhered to (18).

Carbohydrate

Children in the UK achieve 51% of total energy intake from carbohydrate (22); however, children with diabetes find it more difficult to achieve the recommended targets and have a lower reported carbohydrate intake of 49% (23). More practical suggestions may be useful to encourage larger amounts of carbohydrate to prevent excess protein and fat intakes.

Sucrose

Work in adults with diabetes has shown that sucrose has a lower glycaemic index than most starches (24,25). Studies in children have shown no correlation between glycaemic control and 'total' sucrose intake; however, if sucrose is eaten in isolation and excess this will affect control (26,27). These findings support a more liberal approach to sucrose intake when part of mixed meals or mixed with foods with a low glycaemic index, and this more flexible approach to sucrose can make food more palatable to children. It is reasonable to follow the recommendations for sucrose for the general population, that for many countries is less than 10% of total energy. In addition to glucose, sucrose can be used before exercise and for the treatment of hypoglycaemia. A reduction in sucrose must however also be considered in overweight children.

Dietary Fats

Dietary fat intake and the fatty acid composition are important in diabetes because of the associations with cardiovascular disease. The dietary recommendations for fat and fatty acids have been formulated for adults (18) but not separately for children. Therefore the intake of children above 5 years should follow the DRVs for adults. Up to the age of 5 years it is expected that the proportion of energy derived from dietary fats will fall from about 50%, as supplied by breast feeding or infant formula, to those recommended for adults. This change should not occur before 2 years old. In practice this means that the change from whole fat milk to semi-skimmed or even skimmed milk should be delayed until the age of 2. Below this age a high energy density of foods is important, and in addition if low-fat foods are given to toddlers there can be associated rapid gastric emptying and diarrhoea.

Saturated Fatty Acids

A diet low in saturated fat can lower total and low-density lipoprotein (LDL) cholesterol (28), which are strong predictors of coronary heart disease. In European adults with Type 1 diabetes, the saturated fatty acid intake represents 14-17% of total energy (29). In children without diabetes it is 14 (22) and although at the lower end of the adult range, it is above the 10-11% of dietary energy recommended (1,2,3,18). These figures support the view that children as well as adults require greater practical advice on reducing saturated fat intake.

Polyunsaturated Fatty Acids (PUFAs)

The DRV for PUFAs is 6.5% (18); WHO recommendations for the general population are 3-7% (18) and the ISPAD Consensus Guidelines 2000 (1) for children with diabetes are <10% of total energy.

Cis polyunsaturated fatty acids can be divided into two main groups, cis n-3 and cis n-6. These groups have different beneficial biological functions and are found in different foods. Fish oils are the richest source of cis n-3, with seed oils and margarines also providing alternative sources. Cis n-6 polyunsaturated fatty acids are found mainly in plant oils, including soya, corn and sunflower oils, and margarines manufactured from these oils.

In the UK childhood population the average total intake of energy from cis polyunsaturated fatty acid is 6% (22). For infants, children and adults the DRV recommendations (18) are that linoleic acid (cis n-6) should provide at least 1% of total energy and a-linolenic acid (cis n-3) at least 0.2% of total energy. A report on nutritional aspects of cardiovascular disease (30) recommended that no further increase in average intakes in respect of cis n-6 was required but cis n-3 should increase from around 0.1 g a day to 0.2 g. Data are not available for individual fatty acids intakes for the general childhood population, however intakes of total cis n-3 and cis n-6 are above the DRVs set for individual fatty acids (22), suggesting that young people meet the DRV levels. Guidance with emphasis on a good balance of both cis n-3 and cis n-6

seems appropriate, as encouraging moderate intakes of these polyunsaturated fatty acids in a mixed diet will in consequence help to reduce overall saturated fat intake. Supplementation is not recommended as evidence of any benefit is conflicting on LDL cholesterol or glycaemic control.

Cis Monounsaturated Fatty Acids (MUFAs)

Ideally most dietary energy should be derived from a combination of cis MUFAs (13% of total energy) and high soluble-fibre carbohydrate. High MUFA intakes have several potential metabolic advantages including improving insulin sensitivity, glycaemic control and possibly reducing atheroma (28). A major benefit of a higher MUFA diet is palatability and aiding compliance to an otherwise low-fat diet. Donaghue et al. (31) have shown that even a modest increase in monounsaturated fat in adolescents with Type 1 diabetes seemed to improve insulin sensitivity.

The mean MUFA intake for the childhood population without diabetes is 11.8% of total energy (22). The intakes of children with diabetes are likely to be similar, however sources of MUFA in the UK are not as readily available as in other European countries, particularly some of the Mediterranean countries. Practical advice to increase MUFA intake should include promoting olive oil or rape seed oil and other rich sources such as specific margarines with a high monounsaturated fat content.

7rans-isomer Fatty Acids

Some traras-isomers of PUFAs occur naturally but most are formed during partial hydrogenation of vegetable oils to produce margarines and vegetable shortening found in baked goods and pastries. The traras-isomers of PUFAs have similar detrimental metabolic effects as saturated fatty acids and for practical purposes should be considered the same. The present mean intake of children without diabetes is 1.4% of total energy (22).

Lower Fat Snacks

The school snack, mid-morning, is often the most difficult one of the day, as it has to be taken or bought at school, carried in the school bag, and most importantly acceptable to peer group scrutiny. In the UK this often allows for few healthy alternatives as children do not want to eat fruit in front of their friends, in other European countries this is less of a problem as children usually choose much healthier snacks (32). Nevertheless dietary education should centre on lower fat snacks that are familiar to children. The fat content of snacks such as fruit or a bag of crisps can range from 0-12 g fat per portion, respectively, with similar carbohydrate values. The lower fat products such as corn chips, potato sticks, etc. should be encouraged and discussed with the child to help them in selection. Pictorial illustrations are often useful.

V|tamins and Antioxidant Micronutrients

Foods naturally rich in vitamins and dietary antioxidants (tocopherols, carotenoids, vitamin C and possibly flavonoids) should be strongly encouraged. Highly reactive oxygen free radicals are increasingly implicated in the pathogenesis of atherosclerosis and foods rich in antioxidants, such as fresh fruit and vegetables, may provide a means of protecting against long-term cardiovascular disease in populations at increased risk.

Unfortunately the intake of vitamins and dietary antioxidants in the UK is low among young children (22). Scientific evidence on their benefits is still evolving and further research is required in children before firm recommendations can be made. In the meantime it is appropriate to achieve at least the DRVs for vitamins and to promote foods that naturally contain significant quantities of dietary vitamins and antioxidants (33). Present evidence does not support the use of dietary supplementation with vitamins or minerals.

Non-starch Polysaccharide (Previously Known as Fibre)

Non-starch polysaccharides may be classified into two broad categories -soluble (including gums, gels, pectin) and insoluble (including cellulose and lignin). Intakes are recommended to the level suggested for the general population. However intakes may be low in European countries and meeting desired targets may involve considerable change for some children and their families (34). A reasonable first target would be 1 g/100kcal/day (similar to non-diabetic children), rising to 2g/100kcal/day, with emphasis on soluble fibre (20). Soluble fibre can benefit both glycaemic control and lipid metabolism, reducing both fasting and post-prandial glucose values. An improvement in insulin sensitivity is postulated as the mechanism by which soluble fibre can improve fasting hyperglycaemia. The benefits of increasing soluble fibre are supported by studies in children (19). Fruit and vegetables are good sources of soluble fibre and emphasis should be placed on increasing intake, as most children with diabetes, like non-diabetic children in the UK, eat considerably less than the daily five portions of fruit and vegetables recommended (22).

Salt

Salt intake is in general too high and in Western countries difficult to decrease as it is added to many processed foods (only 20% of intake is added at the table and in cooking). Two-thirds of the children in the National Diet and Nutrition Survey had salt added to their cooking and salt was added to food at the table, either usually or occasionally, by about half of the young people (22). Dietary habits are learned in childhood and difficult to change. Therefore these practices should be discouraged for the whole family and practical advice to develop cooking skills to reduce the intake of processed foods would help to reduce salt consumption. Reduction is recommended to that of the general adult population. In most European countries this constitutes a reduction of 50%, to less than 6g of salt daily.

Alcohol

Alcohol has no place in the normal nutrition of young people with or without diabetes, and in many countries alcohol ingestion in children and young teenagers is either illegal or culturally unacceptable. However, since most UK adolescents do experience and experiment with alcoholic drinks the effect of alcohol on their diabetes requires discussion. It is important to explain the risks of alcohol-induced hypoglycaemia and stress the dangers of nocturnal hypoglycaemia induced by inhibition of gluconeogenesis. The benefits of taking complex carbohydrates before, during and after drinking alcohol to reduce the risk of hypoglycaemia need to be explained.

Nutritive Sweeteners

These include glucose, sucrose, fructose and sugar alcohols such as sorbitol. All contain energy and should be considered if weight is a problem. The sugar alcohols have a lower glycaemic response than sucrose and have a slightly lower energy value. Large quantities may cause osmotic diarrhoea and some children are particularly sensitive.

Non-nutritive Sweeteners

These include saccharin, aspartame, acesulfame K, cyclamates, alitame and sucralase and may be used in low-sugar products to improve variety and compliance. Acceptable daily intakes have been established. Fears that these sweeteners may contribute to hyperactivity in children have not been substantiated.

'ACHIEVE AND MAINTAIN IDEAL BODY WEIGHT'

The diagnosis of Type 1 diabetes in a child is usually preceded by weight loss and initially extra energy is required to re-establish optimal weight. The appetite and food intake may double in the first 2-3 weeks after diagnosis and parents need to be reassured that this is a healthy physiological reaction that will settle. This increased appetite is a good opportunity to establish a regular carbohydrate intake and introduce new healthy foods that may become established in the future diet. This is a critical time to ensure that there is not an overshoot towards excessive weight gain.

Weight management during puberty is an important issue. Paradoxically (particularly in girls) energy requirements may actually decrease due to an unfortunate decline in the frequency and intensity of exercise, and when this occurs weight gain can become a problem. Puberty is also associated with insulin resistance and insulin doses need to increase to prevent hyperglycaemia but weight gain may accompany this increase in insulin administration. Regular monitoring of weight and height will help to identify potential weight problems in puberty, too much or too little, and allow insulin, food and weight management advice to be given promptly. Prevention of weight gain is a major priority because it is difficult to lose once gained and often the problem is transferred into adulthood. All aspects of diabetic control are compromised when the body mass index (BMI) rises; insulin sensitivity decreases, glycaemic control deteriorates and dyslipidaemias and hypertension can manifest themselves (35).

Intensive Insulin Management

Intensified insulin therapy to improve glycaemic control may have the negative effect of increasing weight, as demonstrated in the Diabetes Control and Complications Trial (17). Close nutritional supervision and weight management should accompany intensive therapy to prevent weight gain (17,36).

The intensive therapy group in the DCCT also experienced a threefold increase in hypoglycaemia (17). The need to carefully balance nutritional intake to insulin therapy was one of the important conclusions of the DCCT and stressed the importance of dietary re-education when intensified insulin management is introduced. Advice is difficult, as it needs to be directed simultaneously to reducing total energy and the fat/carbohydrate ratio, avoiding hypoglycaemia with regular carbohydrate while improving or maintaining good glycaemic control.

'ACHIEVE AND MAINTAIN OPTIMAL GLYCAEMIC CONTROL ON AN INDIVIDUAL BASIS, BALANCING FOOD INTAKE WITH METABOLIC REQUIREMENTS, PHYSICAL ACTIVITY AND INSULIN TREATMENT'

Initial Consultations

The newly diagnosed child and parent have an enormous volume of information to assimilate. This ranges from factual issues, such as what is diabetes, to technical issues, such as how to inject and adjust insulin and monitor blood sugars. In addition they are given information on what they can eat and how all these factors affect each other. This deluge of information is often overwhelming and frightening. Additional issues that health care professionals may feel important should be considered carefully and where possible delivered later. Initial consultations should be used to develop a trusting relationship with the child and parent establishing rapport, confidence and understanding. This time should be spent on how the child feels, and is coping with the initial tasks of diabetes. The focus should be on their immediate questions and real concerns. Usually the first question parents ask is 'What can we eat?' Useful prompts at these times include:

• ' What are your worries about food and diabetes?''

• 'How will your eating habits at home affect diabetes?''

• 'Do you think you will have to change the way you and the family eat?

It is particularly important to establish if other family members have diabetes and the influence this already has on the family eating pattern.

The interplay of insulin with food, eating habits, the timing of meals and snacks and even a wider discussion of insulin effects on metabolism in general should take place, if appropriate to the individual's level of understanding and perception of diabetes management.

A diet history should be taken to support any changes suggested, although this need not occur at the first appointment, if the parent or child has raised a number of emotional issues and concerns that need addressing. Completion of a food diary for review at a future appointment is often a more productive use of time. All information should be provided at a level appropriate to assist the child to achieve their immediate goals while addressing any concerns. Appropriate information at this stage may be very practical advice for the next supermarket shop or how to read food labels.

Events during the early days and weeks after diagnosis undoubtedly have a lasting impact on long-term control (see Chapter 3) and there is some evidence that if glycaemic control is good in the first 5 years long-term diabetic outcomes are improved (37-39). It is essential that the dietitian is perceived at this important time as being an ally and not prescriptive or dogmatic, taking little notice of immediate fears, crucial cultural and behavioural aspects of the family and their eating pattern. The DCCT showed conclusively that dietitians need to develop skills in communication, counselling and motivational interviewing to facilitate necessary effective changes (36).

Education Methods

The DCCT also showed that meticulous attention to both diet (36,40) and insulin management (17) produced better glycaemic control and reduced complication rates. Dietary education tools need to be selected carefully for each child and family to achieve maximum understanding and compliance.

Educational tools should be varied, appropriate to the needs of the family and staged at a pace with which the family is comfortable. As families become more confident with managing diabetes, education may become more complex and as children grow and take more responsibility, regular re-education is essential. The dietitian should have developed the skills to deliver any of the following methods and in this way the needs of the individual child and family can be met. The mode of transfer of the information should also be appropriate to the child's age and developmental level.

Food pyramids, Figure 5.1, and plate models, Figure 5.2, are useful in providing basic nutritional information and healthy eating concepts. They also illustrate visually carbohydrate in relation to the other food components and should be attractive visual aids for children.

Carbohydrate Management

Many methods of counting or estimating carbohydrate intake are used in paediatric practice, for example, intensive nutritional management with

Figure 5.1 Food pyramid. Reproduced from US Department of Agriculture: Food and Nutrition Information Center, USA

estimation of carbohydrate effects, carbohydrate exchanges, portions/servings, low glycaemic index or a qualitative approach (41,42). There is no consensus in favour of one particular method and some methods are better suited to particular children and families. What is becoming clearer is that if we are aiming at really tight metabolic control to improve diabetes outcomes there seems to be a need for some form of carbohydrate estimation to counterbalance insulin doses (4).

The significant diet behaviours associated with improved HbA1c in the DCCT (40) were:

• Adherence to the agreed meal plan

• Adjusting food and insulin in response to hyperglycaemia

• Appropriate treatment of hypoglycaemia

• Consumption of agreed snacks within the meal plan

The DCCT also showed that intensive nutrition education, not necessarily carbohydrate assessment, with frequent blood glucose monitoring in conjunction

Figure 5.2 Plate model. Modified from: ©Diabetes UK. This figure has been reproduced with the kind permission of Diabetes UK. Adapted February 2001, from the Balance of Good Health: Food Standards Agency

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