Crohn's and Colitis Foundation of America, Diet and Nutrition
"Is IBD caused by allergy to food?
No. Although some people do have allergic reactions to certain foods, neither Crohn's disease nor ulcerative colitis is related to food allergy. People with IBD may think they are allergic to foods because they associate the symptoms of IBD with eating."
"
Immune sensitization to food, yeast and bacteria in Crohn’s disease" in
Alimentary Pharmacology and Therapeutics (2001) [full article]
Discussion: "This study has demonstrated a marked sensitization to a broad range of food, bacterial and yeast antigens in patients with Crohn’s disease.
... Disease distribution, disease activity and the use of drug therapy, did not appear to influence the patients’ lymphocyte responses to the antigens tested.
... Whether the lymphocyte sensitization to lumenal antigens in Crohn’s disease is due to breached epithelium or is a part of the pathogenic process in some other way, such as a general immune cell hyper-responsiveness, is unknown.
... Crohn’s disease patients demonstrated abnormal rectal blood flow responses to yeast and citrus fruits, when group data were analysed."
Conclusions: "... These sensitized lymphocytes may contribute to the inflammatory process."
"
Gut mucosal response to food antigens in Crohn's disease" in
Alimentary Pharmacology and Therapeutics (2002) [full article]
"This study has shown that patients with Crohn's disease have a
markedly increased response to food antigens, demonstrated both
in vivo and
in vitro, compared with healthy subjects. Markedly increased responses were observed to all the food antigens tested in the Crohn's disease patients, although the particularly stringent statistical criteria which were applied suggested that the
most significant responses occurred to yeast and citrus fruits. ...
Whether the immunological and vascular changes observed are primary or secondary events in the pathogenesis of Crohn's disease remains to be determined. The responses obtained in patients with Crohn's disease may be secondary to sensitization that has occurred due to the breached gut epithelium, although substantial evidence suggests that antibody responses do not occur in other conditions in which the epithelium is breached, such as ulcerative colitis. If related to breached epithelium, the response may result from a genetically determined susceptibility.
... Even if these are secondary events, the dramatic
in vivo changes in blood flow support the possibility that this sensitization is of clinical relevance. These data, together with the clinical response to purified liquid diets, provide strong evidence for a
pivotal role in the ongoing inflammation which characterizes this disease.
... Given that
food exposure is greatest in the proximal gut, it might be that disease is more common in the distal small bowel and colon. We do not believe that exposure to food antigens is the primary abnormality in Crohn's disease. However, exposure to food in the proximal gut may lead to immune sensitization, as demonstrated by several techniques in this study, resulting in activation of immune cells which circulate and re-home to where they are most concentrated (the ileum), with resultant mucosal inflammation.
... Although the strongest data were obtained for a response to citrus fruit and yeast antigens, the individual data supported the possibility of
an abnormal response to the full range of antigen groups tested. In an individual, any one or more of these protein groups may be important.
... In a study of patients with Crohn's disease, ulcerative colitis, other miscellaneous diarrhoeal illnesses and healthy controls,
the presence of ASCA was strongly associated with Crohn's disease,
in particular small bowel disease. ... IgG and IgA ASCA were significantly raised in Crohn's disease, especially in the presence of small bowel disease.
... The specificity of the antibody response in Crohn's disease to
S. cerevisiae, but not to
Candida albicans, further supports the concept that
ASCA are not simply the result of a generalized increase in intestinal permeability.
... Levels of IgE/IgG anti-IgE immune complexes were determined.
In Crohn's disease sera, no food-specific IgE could be detected, but levels of immune complexes of IgE and IgG anti-IgE autoantibodies were significantly increased compared to healthy controls.
... If sensitized lymphocytes and specific antibodies play a pathogenic role,
the exclusion of relevant foods may provide therapeutic benefit, even in the short term.
... there were no differences between patients and controls in skin antigen testing. This finding is in agreement with other reports of
the failure of skin testing to diagnose food sensitivities in patients with suspected food allergies or inflammatory bowel disease. This difference between skin testing and blood and gut testing also suggests distinct compartmentalization of immune responses, with gut sensitization leading to a specific gut response." [emphases mine]
"
What Is the Role of Food Allergy and/or Intolerance in the Genesis of IBD?" in
General Gastroenterology (2006)
"True food allergies constitute a different pathogenesis and pathology from true IBD. Although the true cause of IBD remains elusive, it appears to involve a combination of genetic susceptibility, immune dysregulation, and environmental pressures. Patients with IBD are more likely to suffer from food allergies or intolerances than the normal population, but there is not good evidence to suggest that an allergy is the trigger for the underlying inflammatory process. Whereas some groups have been able to demonstrate immune responses to certain food antigens in patients with Crohn's disease, these findings cannot be replicated in other populations, making this mechanism for a pathogenesis unlikely. In patients with subclinical disease, an allergy can precipitate IBD phenotypes, but again, the link between allergies and causation is weak. Certainly those patients who have undiagnosed food intolerances are less likely to respond to standard IBD therapies.
Patients should be counseled regarding their dietary habits to monitor which specific foods or food groups may trigger worse gastrointestinal or systemic symptoms. Elimination diets, however, are rarely needed in the IBD patient."
"Clinical Relevance of IgG Antibodies against Food Antigens in Crohn’s Disease: A Double-Blind Cross-Over Diet Intervention Study" in
Digestion (2010)
Results: "The
daily stool frequency significantly decreased by 11% during a specific diet compared with a sham diet. Abdominal pain reduced and general well-being improved. "
Conclusion: "A nutritional intervention based on circulating IgG antibodies against food antigens showed effects with respect to stool frequency. The mechanisms by which IgG antibodies might contribute to disease activity remain to be elucidated." [emphasis mine]
My 5% better comment: If 10 trips to the bathroom are the norm, this would be reduced by 1. If each trip takes on average 15 minutes, this would save approximately 8 hours per month, which is the equivalent of one working day. Would identifying IgG antigens and eliminating them be meaningful for a CDer? You bet.
