Topic Highlight
Copyright ©2012 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Gastroenterol. Aug 7, 2012; 18(29): 3814-3822
Published online Aug 7, 2012. doi: 10.3748/wjg.v18.i29.3814
Impact of environmental and dietary factors on the course of inflammatory bowel disease
Eduard Cabré, Eugeni Domènech
Eduard Cabré, Eugeni Domènech, Inflammatory Bowel Disease Unit, Department of Gastroenterology, Hospital Universitari Germans Trias i Pujol, 08916 Badalona, Spain
Eduard Cabré, Eugeni Domènech, Network for Biomedical Research in Liver and Digestive Diseases (CIBEREHD), 08036 Barcelona, Spain
Author contributions: Both authors designed the outline of the review; Domènech E wrote the sections on smoking, non-steroidal anti-inflammatory drugs and intestinal infections; Cabré E wrote the sections on diet and other environmental factors; both authors approved the final version of the manuscript.
Correspondence to: Eduard Cabré, MD, PhD, Inflammatory Bowel Disease Unit, Department of Gastroenterology, Hospital Universitari Germans Trias i Pujol, Carretera del Canyet s/n, 08916 Badalona, Spain.
Telephone: +34-93-4978909 Fax: +34-93-4978951
Received: February 6, 2012
Revised: March 26, 2012
Accepted: March 29, 2012
Published online: August 7, 2012

Besides their possible effects on the development of inflammatory bowel disease (IBD), some environmental factors can modulate the clinical course of both ulcerative colitis (UC) and Crohn’s disease (CD). This review is mainly devoted to describing the current knowledge of the impact of some of these factors on the outcome of IBD, with special emphasis on smoking and diet. Although the impact of smoking on the susceptibility to develop CD and UC is firmly established, its influence on the clinical course of both diseases is still debatable. In CD, active smoking is a risk factor for postoperative recurrence. Beyond this clinical setting, smoking cessation seems to be advantageous in those CD patients who were smokers at disease diagnosis, while smoking resumption may be of benefit in ex-smokers with resistant UC. The role of dietary habits on the development of IBD is far from being well established. Also, food intolerances are very frequent, but usually inconsistent among IBD patients, and therefore no general dietary recommendations can be made in these patients. In general, IBD patients should eat a diet as varied as possible. Regarding the possible therapeutic role of some dietary components in IBD, lessons should be drawn from the investigation of the primary therapeutic effect of enteral nutrition in CD. Low-fat diets seem to be particularly useful. Also, some lipid sources, such as olive oil, medium-chain triglycerides, and perhaps omega-3 fatty acids, might have a therapeutic effect. Fermentable fiber may have a role in preventing relapses in inactive UC.

Keywords: Environmental factors, Dietary factors, Nonsteroidal anti-inflammatory drugs, Smoking, Infections, Inflammatory bowel disease