Review article: dietary and nutritional management of Crohn's disease.

The value of dietary alteration and the nutritional management of Crohn's disease is assessed in this review. Lactose restriction, low-fat diets and low-residue diets may be of value in specifically indicated clinical situations. A fibre-rich, unrefined carbohydrate diet has not been shown to alter the course of the disease, and the value of 'exclusion diets' remains to be confirmed in controlled, prospective studies. Nutritional insufficiency of varying degrees is common in Crohn's disease and can be corrected by the efficient use of enteral diets (usually with polymeric preparations) or intravenous nutritional support. Growth retardation in adolescents with Crohn's disease can usually be improved by enteral nutrition. Nutritional support of various kinds may be of value in the management of local complications of Crohn's disease; sub-acute obstruction, anal, perianal and rectal lesions, fistulas and ileostomy complications, and the management of bile acid-induced diarrhoea. The use of nutrition as 'primary therapy; in Crohn's disease is considered. Theoretical reasons why nutritional support and bowel rest may possibly induce remission of the disease are discussed. The evidence to date suggests that intravenous nutrition and bowel rest may not be effective in inducing a primary remission of the disease, and the possible value of elemental diets and polymeric diets in this respect are assessed. Further prospective controlled studies of elemental diets as primary therapy in Crohn's disease are required.