Absorption of food occurs within the small bowel. The process involves
breakdown of macromolecules by enzymes and transport across the specialised
small bowel mucosa. Disorders of any of the elements potentially leads to
malabsorption. The most common causes of malabsorption are pancreatic
insufficiency, coeliac disease, resection of the ileum, Crohn’s disease and
liver disease (see Fig. 4.8).