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Paediatric nutrition as a new subspecialty: is the time right?
  1. MRC Childhood Nutrition Research Centre
  2. Institute of Child Health
  3. 30 Guilford Street
  4. London WC1N 1EH

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    Scientific interest in nutrition in early life preceded the formal development of paediatrics. Building on biochemical studies of the 18th century,1 Franz Simon underpinned a rational, scientific basis for infant feeding with his landmark work in 1838,2 when the word ‘paediatrics’ had not even entered the English language.3 This was 20 years before the first chair of paediatrics in the US and a century before paediatric chairs were created in Britain (1930s). By then, the field of paediatric nutrition had already passed many major milestones,4 for instance the scientific understanding that led to prevention and treatment of infantile scurvy and rickets.5 6 In 1940 the editors of Holt’s Diseases of Infancy and Childhood (11th edition) stated ‘Nutrition in its broadest sense is the most important branch of paediatrics’.7 Given the extraordinary scientific effort and interest over the past two centuries, it is paradoxical that nutrition has never emerged as an independent paediatric specialty, when other areas of much more recent focus have done so.

    Why should this be so? Firstly, the intensive interest in nutrition largely solved the earlier concerns. With the exception of iron deficiency anaemia, primary nutritional deficiency diseases are now uncommon in the West. Secondly, other specialties have evolved partly from the need to master specialised techniques (for example cardiac catheterisation); yet, until recently there have been few such techniques in clinical nutrition. Thirdly, medical specialties have been based traditionally on organ systems, a categorisation into which a broad, multidisciplinary subject like nutrition does not fit. Consequently, nutrition has been fragmented and subsumed piecemeal into other fields—enteral nutrition into gastroenterology, intravenous feeding into surgery, growth into endocrinology and so forth.

    However, there has now been a significant shift in thinking about nutrition from a preoccupation with meeting nutrient needs to a concern about its impact on health outcomes, including adult degenerative diseases, cancer, and cognitive function.8-15 After smoking, nutrition and exercise (a related province of nutrition) are purported to be the major lifestyle factors associated with cardiovascular morbidity,16 which has its origins in childhood and is the principal cause of death in the West.

    Perhaps the most exciting area of current interest is the idea of ‘programming’.17 This is the concept that nutrition is a key environmental influence that may act on the genome during critical periods with long term or life time effects on the organism.18 Numerous studies in animals, including primates, show that brief periods of dietary manipulation during critical or sensitive windows in early life may program outcomes of considerable public health and clinical significance were they to apply to humans, including lifelong effects on lipid and carbohydrate metabolism, body fatness, blood pressure, development of atherosclerotic lesions, and neurodevelopment.19-23Indeed recently, experimental and epidemiological studies now strongly indicate that early nutrition is a key factor for such outcomes in humans.8 14 15

    Concurrently, increasing evidence supports the view, discussed in this article, that effective clinical nutritional management in paediatrics may have more immediate influence on progression of major disease states, disease complications, response to treatment, and on hospital admissions or their duration.24-28

    This refocusing of paediatric nutrition towards the impact of nutrition on both immediate and long term health has drawn new bioscientific, clinical, epidemiological, and health economic expertise into the field. The evidence on the importance of early nutrition has critical implications for public health and clinical practice, and for service providers and purchasers.

    A case for paediatric nutrition as a distinct specialty

    Given this new direction, the issue now is whether paediatric nutrition should be a recognised discipline within paediatrics. In approaching this, I shall address three general questions: is there anacademic case, a clinical case, and afinancial one ?

    (1) Academic case: are there readily identifiable deficiencies in current nutritional practice, education, and research that would benefit from academic development of the field ?

    • With few ‘nerve centres’ in paediatric nutrition, an agreed standard of clinical practice has not developed and paediatricians have had to acquire nutritional skills in an ad hoc way. Not surprisingly, clinical opinion and therefore patient management varies greatly. Standards of nutritional practice in the community have been equally inconsistent. Various official and semiofficial recommendations have been conflicting and patchily understood. And while advisory bodies attempt to carve out more consistent, evidence-based nutrition policy, there are fewrecipients for such advice in terms of centres that can secondarily process and disseminate key messages to practitioners. The result is professional and parental uncertainty over nutritional care.

    • Education in paediatric nutrition has been recognised as a priority area for development. As yet it remains deficient at every stage: preclinical, clinical, and postgraduate. Higher training in nutrition would generally depend on chance local interests.

    • A key objective for clinical research should be to prove outcome benefits for recommended managements. Yet the critical issue of whether early nutrition influences health outcomes or development has, only recently, been formally approached. Disturbingly, most recommendations of expert bodies on fundamental areas of practice must be based, largely, on theoretical considerations. These deficits sharply contrast with the major research investment in nutritional physiology, which has received more research attention than any other area of paediatrics. For instance, as far back as 1953, Macy reviewed over 1500 publications on breast milk composition29 —just one small area of infant nutrition. This profusion of nutritional studies in the face of the paucity of outcome data justifying clinical practice implies that clinical nutritional research has lacked direction.

    It seems reasonable to expect that the focusing of clinical research and the need to develop consistent standards of clinical practice, education, and training in paediatric nutrition would now be best served by formal development of the discipline.

    (2) Clinical case: are there defined areas of paediatric nutritional practice that require specialised attention and expertise ?

    Certainly, even with good paediatric dietetic services. Nutritional advice is probably the commonest category of advice sought by parents. In clinical paediatrics, nutrition is one of the major problem areas—virtually every sick infant in neonatal intensive care and a significant proportion of sick children could benefit from more specialised nutritional attention. In some situations, including iron deficiency anaemia, obesity (incidence now increasing apace), and long term parenteral nutrition, nutrition may be the principalclinical issue.

    Malnutrition, unacceptably often identified in hospitalised medical and surgical patients of all ages, if not effectively treated by enteral or parenteral nutrition, may increase infection risk, reduce wound healing, increase the need for high dependency or intensive care, increase hospital stay, and increase risk of complications or death.27 28

    A recent review by Booth emphasises that intensive intragastric or transpyloric feeding is effective in inducing remission, promoting long term growth and reducing relapses in Crohn’s disease; can arrest pulmonary deterioration in cystic fibrosis; possibly reduces spasticity in cerebral palsy; reduces need for surgery in gastro-oesophageal reflux, and improves the clinically important malnutrition that accompanies chronic liver disease, congenital heart disease, and malignancies.24 Ledermann and coworkers show that intensive nutritional management of children with renal disease has a major impact on growth and symptoms of renal failure,25and probably reduces hospital stay, the need for more expensive treatments (for example growth hormone), and may delay the need for renal dialysis.

    In preterm infants, the complex enteral nutritional management required may reduce very expensive hospital stay and may significantly increase later neurodevelopment and IQ (A Lucas et al 14 15 and unpublished), with important implications for these babies’ future education and employment.

    Formal organisation and provision of clinical services with a multidisciplinary nutrition team has been shown to reduce catheter sepsis, metabolic complications, and clinical outcome.27 28 For instance, Puntis and coworkers showed that specialised training of staff in a children’s hospital dramatically reduced catheter sepsis from 45% to 8%.26

    Furthermore, new specialised nutritional techniques are becoming suitable for clinical use. They include calorimetry, isotope probes (for instance the dual isotope approach to energy expenditure30 31), a wide range of non-invasive or minimally invasive body composition techniques, methods for assessment of bone mineral content (for example dual x ray absorptiometry), and sophisticated anthropometric tools. These techniques require specialist training and a new generation of motivated clinicians to pioneer their use in practice.

    There appears, therefore, to be a convincing clinical case for specialised nutritional services and training in paediatric nutrition. Without these, many children will receive suboptimal care, with implications for their wellbeing, prognosis, and long term outcome.

    (3) A financial case: are there compelling data for purchasers ?

    The clinical case outlined above has important cost implications. The evidence that good training and service provision in nutrition can reduce hospital admissions, the length of hospital stay, the level of care required and costly complications of treatment, is likely to be an important factor in the development of the field.

    In recent publications, for instance, the British Association for Parenteral and Enteral Nutrition have derived several worked examples, albeit in adult patients, of expected cost savings achieved by nutritional interventions and provision of specialised services.27 28 Thus, provision of nutritional support to undernourished patients in hospital could save, conservatively, a national expenditure of £266 million/ year and the estimated cost saving provided by a nutrition team in preventing catheter sepsis alone is in the range £1650 to £5000 per septic episode.

    Numerous areas of potential cost savings need to be derived more specifically for the paediatric population, but it seems likely that investment in paediatric nutrition would be richly rewarded.

    Is the time right?

    Yes and no. The biological, epidemiological, and clinical research that now underpins the importance of early nutrition, the need to improve standards of practice, education, and training and the potential financial benefits of formal nutritional services, could be seen as immediate signals for the development of the field. However, it seems unlikely that this will happen out of the blue. Prerequisites include:

    • Further collation of data on clinical service needs and on the cost savings of providing them to develop a widely accepted and compelling case for purchasers—though the foregoing provides a basis for such a case.

    • Development of ‘centres of excellence’ to provide academic training for new specialists in nutrition.

    • Nutrition education and training as a prominent part of the professional development of every future consultant; and for those intending to specialise, more intensive nutrition education made available, for instance masters or diploma training.

    • Development and reorganisation of clinical services in all paediatric units to provide a nationally consistent standard of care and suitable milieu for the acquisition of clinical expertise by paediatricians, dietitians, nurses, and related professionals. Specific allocation of nutrition beds in larger centres could provide for management of more difficult cases and a focus for training. Initially the running of nutrition services would inevitably be steered by those with pre-existing expertise (for example gastroenterologists and surgeons), but with gradual increase in prominence of a new breed of paediatric nutrition specialists entering the field de novo.

    What would a specialist in paediatric nutrition actually do?

    Such specialists would lead the nutrition team in collaboration with dietitians, providing nutritional advice across the specialties and in intensive care units, manage specific nutritional problems (inpatient and outpatient), provide regional advice on nutrition, use and develop specialised investigative facilities (body composition tools, energy metabolism techniques, isotope probes, etc), liaise with dietitians and paediatricians to develop clinical nutrition policies, develop community services for nutritional management (for example home parenteral nutrition, post-discharge nutrition of preterm infants, etc), set up training programmes for health professionals in hospital and community and undertake audit. Such specialists would facilitate clinical research that underpins public health and clinical practice.

    Will it fly?

    Sooner or later, yes. Various US centres are considering this direction, though no formal development has taken place. Britain, with its unusual and long standing confluence of expertise, may be best placed to spearhead the development of academic paediatric nutrition.

    Clearly, if we think infant and childhood nutrition matters, both in the short term and for later health and development, then it can no longer be seen as a secondary issue or simply a matter of personal choice and we need to rationalise and improve current practice.