During the past 20 years there has been growing interest in the import
ance of nutritional factors in the pathogenesis of inflammatory bowel
disease. There are so far no definite links between ulcerative colitis
and diet, but links with Crohn's disease have been studied by both ep
idemiologists and clinicians. Epidemiological studies, although retros
pective, have suggested that patients with Crohn's disease eat more su
gar and sweets that control individuals; however, when dietary sugar i
s restricted, there is little clinical benefit. The clinical approach
to nutrition in Crohn's disease has been by the use of elemental diets
, which will produce symptomatic and objective remission in up to 90%
of compliant patients. Those who return to normal eating soon relapse
but, in some studies, have enjoyed prolonged remission on exclusion di
ets. The foods excluded have been not sugar, but predominantly cereals
, dairy products and yeast. Attention has now switched to the possible
harmful role of fat in Crohn's disease. The efficacy of elemental fee
ds appears to depend not on the presentation of nitrogen but on the am
ount of long chain triglyceride present. Increases in recent years in
the frequency of Crohn's disease in Japan have been correlated with in
creased dietary fat intake, and a recent study suggested that W-3 fatt
y acids, which are metabolized by immunomodulatory leukotrienes and pr
ostaglandins, may have a beneficial role to play. The links between nu
trition and Crohn's disease have now become strong and the role of fat
may be the most exciting of all. (C) 1998 Rapid Science Ltd.