Nutritional support may be necessary after treatment of small intestinal cancers. This is especially so after a major portion of the small bowel has been removed or if the duodenum or terminal ileum have been removed or bypassed. These procedures result in poor absorption of iron, calcium , folate, vitamin B12, fat and fat-soluble vitamins and pancreatic/biliary digestive secretions, leading to deficiencies in essential nutrients. Nutritional replacement programs can correct these deficiencies ( see "Maintaining Good Nutrition" ).