The nutritional consequences of gastrointestinal disease in adolescence

The growth spurt of adolescence, during which body weight nearly doubles and height increases by 16%, demands an increased delivery of nutrients by the gastrointestinal tract. Chronic disorders of digestion and absorption at this age, therefore have a potentially profound effect upon growth, skeletal maturation and sexual development. Moreover, the emotional climate of adolescence, which requires affiliation with peer groups, and a distancing from authority figures such as doctors and parents, is often associated with a deterioration in drug and dietary compliance and with erratic clinic attendance. Nutritional problems in adolescent patients with Crohn's disease, cystic fibrosis and coeliac disease are the most common. About one third of adolescents with Crohn's disease experience growth failure and delayed sexual development, probably as a consequence of long-term undernutrition. There is a strong argument for the care of these patients being in the hands of paediatric gastroenterologists. Enteral nutrition, often administered overnight, is successful in inducing catch-up growth, and reducing steroid dosage, although resection of diseased gut is often followed by good growth, and surgery should not be overlooked. Cystic fibrosis in adolescence is commonly complicated by protein-energy malnutrition. Pathogenesis includes anorexia, maldigestion and an increase in resting energy expenditure. Malnutrition has been treated by a number of enteral regimens. In general, there is no place for repeated, short-term interventions of less than 6 months. Long-term studies have all shown good nutritional repletion and growth, but results with respect to improved respiratory function are conflicting. More prospective control trials are needed before the precise indications for enteral nutrition in cystic fibrosis can be accurately defined. Once started it is difficult to stop, although preoperative treatment of patients awaiting heart-lung transplantation seems entirely appropriate. The major problem in the management of coeliac disease in adolescence is dietary compliance. Even those patients who claim to have good dietary compliance often have jejunal biopsy evidence of gluten ingestion and tend to be underweight. This is particularly worrying, as after 5 years adherence to a gluten free diet, the increased risk of gastrointestinal malignancy appears to return to normal.