Nutritional consequences and nutrition therapy in Crohn's disease.

75% of hospital patients with Crohn's disease (CD) suffer from malnutrition and one third of CD patients have a body mass index below 20. Inflammatory bowel diseases (IBD) patients have many vitamin and nutrient deficiencies which can lead to important consequences such as hyperhomocysteinemia which is associated with a higher risk of thromboembolic disease. Nutritional deficiencies in IBD patients are the result of insufficient intake, malabsorption and protein-losing enteropathy as well as the metabolic distubances directly induced by the chronic disease and its treatments, in particular corticosteroids. Screening for nutritional deficiencies in chronic disease patients is warranted. Managing the deficiencies involves simple nutritional guidelines, vitamin supplements, and nutritional support in the worst cases, in particular in children in order to limit the impact of IBD on growth. In active CD, enteral nutrition is the first line therapy in children and should be used as sole therapy in adults mainly when treatment with corticosteroids is not feasible.