Review article: the association of diet with onset and relapse in patients with inflammatory bowel disease

BackgroundThe role of diet in inflammatory bowel disease (IBD) is supported by migration studies and increasing incidences in line with Westernisation. AimTo give a complete overview of studies associating habitual diet with the onset or relapses in ulcerative colitis (UC) or Crohn's disease (CD). MethodsA structured search in Pubmed, the Cochrane Library and EMBASE was performed using defined key words, including only full text papers in English language. ResultsForty-one studies were identified, investigating onset (n=35), relapses (n=5) or both (n=1). Several studies reported high intake of sugar or sugar-containing foods (n=7 UC, n=12 CD), and low intake of fruits and/or vegetables (n=5 UC, n=10 CD) to be associated with an increased onset risk. However, these findings could not be confirmed by similar or higher numbers of other studies. A possible protective role was found for grain-derived products in CD onset, but results were inconsistent for dietary fibre in UC and CD and grain-derived products in UC. No definite conclusions could be drawn for unsaturated fatty acids (UFA), protein and energy intake due to limited and/or inconsistent results. Six studies reported on diet and relapse risk, of which only two (n=1 UC, n=1 CD) had a prospective follow-up. ConclusionsThe current evidence is not sufficient to draw firm conclusions on the role of specific food components or nutrients in the aetiology of IBD. Furthermore, large prospective studies into the role of habitual diet as a trigger of relapses are needed, to identify new therapeutic or preventive targets.