Nutrition and gastrointestinal disease.

Nutrition and intestinal function are intimately interrelated. The chief purpose of the gut is to digest and absorb nutrients in order to maintain life. Consequently, chronic gastrointestinal (GI) disease commonly results in malnutrition and increased morbidity and mortality. For example, studies have shown that 50-70% of adult patients with Crohn's disease were weight-depleted and 75% of adolescents growth-retarded. On the other hand, chronic malnutrition impairs digestive and absorptive function because food and nutrients are not only the major trophic factors to the gut but also provide the building blocks for digestive enzymes and absorptive cells. For example, recent studies of ours have shown that a weight loss of greater than 30% accompanying a variety of diseases was associated with a reduction in pancreatic enzyme secretion of over 80%, villus atrophy and impaired carbohydrate and fat absorption. Finally, specific nutrients can induce disease, for example, gluten-sensitive enteropathy, whilst dietary factors such as fibre, resistant starch, short-chain fatty acids, glutamine and fish-oils may prevent gastrointestinal diseases such as diverticulitis, diversion colitis, ulcerative colitis, colonic adenomatosis and colonic carcinoma. The role of dietary antigens in the aetiology of Crohn's disease is controversial, but controlled studies have suggested that elemental diets may be as effective as corticosteroids in inducing a remission in patients with acute Crohn's disease. In conclusion, nutrition has both a supportive and therapeutic role in the management of chronic gastrointestinal diseases. With the development of modern techniques of nutritional support, the morbidity and mortality associated with chronic GI disease can be reduced. On the other hand, dietary manipulation may be used to treat to prevent specific GI disorders such as coeliac disease, functional bowel disease, Crohn's disease and colonic neoplasia. The future development of nutria-pharmaceuticals is particularly attractive in view of their low cost and wide safety margins.