Crohn’s disease

The diagnosis of Crohn’s disease

There is no single diagnostic test for the diagnosis. Instead, it is the sum of several examinations like blood analysis, stool test, ultrasound scan, colonoscopy or gastroscopy. To ensure the right therapeutic steps, the extent and the severity of the inflammation need to be defined.

The causes of Crohn’s disease

CD mostly affects individual sections of the gastro-intestinal tract; most often the transition of the small intestine to the colon. The inflammation may cover the entire intestinal wall and even organs outside the intestine such as joints, eyes and skin. A particular genetic profile may predispose persons to develop CD.

Recent studies indicate that foods can trigger such inflammations, for example through a type III food allergy. A diet based on the elimination of such foods could supplement the standard drug therapy with anti-inflammatory medications such as corticosteroids.

The scientific approach to Crohn’s disease and IgG

Food as a trigger of Crohn’s disease has long been discussed in literature. As CD is an inflammatory disease, IgG antibodies could also play an important role in the disease when other factors can be excluded.

In a study published in 2010, an exclusion diet was performed upon presence of IgG to food (“Clinical relevance of IgG antibodies against food antigens in Crohn’s Disease: A double-blind cross-over diet intervention study”, Bentz et al., Digestion 2010; 81:252-264). 79 CD patients and 20 healthy persons in a control group were examined for IgG. Afterwards, the clinical relevance of these food IgG antibodies was assessed in a double-blind cross-over study with 40 patients. Based on the IgG antibodies, an elimination diet was planned. Increased quantities of food-specific IgG antibodies were detected in CD patients. A statistically significant reduction in stool frequency compared to the control group was achieved when the CD patients complied with the specific elimination diet.

Another study aimed to show the effect of the intake of IgG positive food in CD patients in remission (“The effects of provocation by foods with raised IgG antibodies and additives on the course of Crohn’s disease: A pilot study”. Uzunismail et al., Gastroenterol 2012; 23 (1): 19-27). In all patients, increased markers of intestinal inflammation, abdominal symptoms as well as histological evidence were found after a 3 day food challenge with IgG positive food. The authors concluded that foods with raised IgG antibody levels and food additives can provoke the symptoms and may stimulate the inflammation in patients with CD.