The Diagnostic Predictability of Food Allergy Testing
Condition: Irritable Bowel Syndrome (IBS)
MeSH terms: Irritable Bowel Syndrome; Hypersensitivity; Food Hypersensitivity; Syndrome
Study type: Interventional

Summary: 
      Irritable bowel syndrome (IBS) sufferers often find that specific foods can exacerbate their
      symptoms; identifying which foods involves a long and arduous process. Different food allergy
      tests are marketed to IBS sufferers and healthcare practitioners as an easy way to identify
      these offending foods. Which test method might be best to use? This project compares the
      results of different food allergy methods versus an elimination/challenge diet to determine
      which method maybe superior in IBS sufferers.
    

Detailed description: 
      A variety of methods are available to assess food items that an individual with IBS may not
      tolerate well. No study has compared the predictability of each method to the results of an
      Elimination/Challenge (E/C) diet in individuals suffering from IBS and, or assessed which
      method might more accurately identify Non Immune Mediated Food Allergies (NIMFAs) in IBS
      suffers' An understanding of the relative agreement between these tests may help patients and
      practitioners make better decisions around how to best investigate NIMFAs for IBS and inform
      the design of larger studies on this topic.

      The primary objective of this study is to determine the ability of each different laboratory
      method of food testing (IgG titres, Cytotoxic assay and electrodermal screening methods) for
      food reactivity to predict those foods that an individual with IBS reacts as assessed via an
      elimination diet in an adult population diagnosed with IBS by ROME III criteria and a score
      of greater than 200 on the IBS Severity Scoring System.

      The secondary objective is determine inter-method agreement, at the individual level, between
      the sensitivity of food identified via each laboratory method, overall and according to
      severity of the reaction (high, medium, low, and no reaction).

      The third objective is to measure the impact of the elimination of possible food allergies on
      the symptoms of IBS in the participants.

      The fourth objective is to determine whether intestinal permeability maybe contributing to
      the symptomatology of IBS as assessed via an intestinal permeability test.

      The fifth objective is to determine whether, after a period of eliminating potentially
      reactive foods, this provides some healing benefit to the gastrointestinal tract.

      3. Study Design

      This correlative and hypothesis generating pilot study is to be conducted at a single
      investigational site. This study will be open to members of the public, staff, and students
      of Canadian College of Naturopathic Medicine (CCNM) and patients of the Robert Schad
      Naturopathic clinic (RSNC) who suffer from IBS. The study will be conducted at CCNM in the
      Integrated Health Center (IHC).

      Individuals who are interested in participating will be screened by two naturopathic doctors
      for their suitability. The screening process involves an assessment of the inclusion and
      exclusion criteria, confirmation of symptoms of IBS and of their ability to commit to and
      follow through on dietary restrictions. A second meeting with another member of the study
      team will also occur. Team members will confer and agree upon all study participants
      selected. The study participants will be contacted by phone and invited to participate in the
      study. The first visit will be scheduled at this time and a copy of the E/C diet guidelines
      emailed to the individual.

      At the first visit, study participants will complete the Study Case Report, provide the
      necessary blood samples for the laboratory tests, undergo the electrodermal screening for
      food allergies, complete necessary symptoms tracking forms and provided with an intestinal
      permeability test to complete at home prior to initiating the elimination phase of the study.
      The E/C diet guidelines will be reviewed and any questions answered.

      Study participants will be contacted by telephone during week 2 of the study by a member of
      the study team to address any dietary questions that may have arisen during the first week of
      the elimination diet.

      Subjects will return to the clinic at weeks 3, 5, 7 and 9 for completion of the validated
      questionnaires, review of study diary, query of adverse events, and compliance monitoring.

      At visit 3 (week 5), study participants will also receive the list of food items that will be
      introduced during the challenge portion of the study. The study participants will be provided
      with a second intestinal permeability test to complete at home prior to initiating the
      challenge phase of the study.

      The study participants and study team members will remain blinded to the results of the all
      tests until the completion of the study.

      The primary endpoint of the study is the degree of agreement between the food items
      identified as eliciting a reaction through an elimination/challenge diet versus those food
      items identified through laboratory testing. Cohen's kappa will be the statistical measure to
      assess agreement.

      The secondary endpoint of the study is the degree of inter-laboratory agreement of
      reactionary food items across all of the methods (laboratory and electrodermal screening)
      used in the study. Cohen's kappa will be the statistical measure to assess agreement.

      The third endpoint of the study is the change in the scores on the irritable bowel severity
      scoring system and FAST symptom checklist between the end of the elimination diet phase and
      baseline (start of the study). The irritable bowel severity scoring system is a validated
      questionnaire used to monitor irritable bowel syndrome. This scoring system incorporates
      measures of pain, distension and bloating due to gas, bowel dysfunction (constipation and
      diarrhea) and quality of life/global well being and has been validated as a reproducible and
      sensitive means of measuring symptoms associated with IBS.

      A numerical scale, from 0 to 10 will be used as a measure of symptom severity on the FAST
      Study Diet & Symptoms Diary tracking forms.

      The FAST symptom checklist was documented by Dick Thom, a naturopathic doctor, in his book
      "Coping with Food Intolerances: Surviving the nineties." This checklist serves as a quick and
      easy method for study participants to note the symptoms that they are experiencing and their
      severity according to a rating scale provided on the checklist.

      Study Duration Upon successful screening, washout period (if necessary), study participants
      will participate for the full 9 week active treatment duration. At baseline (week 1), study
      participants will complete validated IBS symptom questionnaire, the FAST Study Symptom
      checklist, blood samples will be taken for the necessary food allergy testing and
      electrodermal screening will be performed. Study participants will return to the clinic at
      weeks 3, and 5, 7, and 9 to complete the validated IBS symptom questionnaire and FAST Study
      Symptom checklist. During all study visits, study participants are queried for adverse
      events, study diaries will be reviewed, and compliance will be monitored via diet diary.
      Study participants will also be re-queried for compliance with the exclusion criteria of the
      protocol primarily with respect to confounding factors such as new medications, or natural
      health products. Study visits 3 through 7 are expected to take approximately 30 minutes. The
      first visit will take 1.5 hours and the final visit 45 minutes.
    

Intervention name(s): Elimination/Challenge Diet
Intervention type(s): Other
Intervention description(s): An pre-specified elimination diet contains a list of food items permitted to be consumed by the study participants. These food items, selected to be consumed are whole foods of low allergenicity.
The challenge phase of the diet involves introducing 8 different foods at three days intervals. the selected challenge foods will be selected based on a review of the non-IgE mediated food allergy test results by a third-party, not directly associated with the project team.
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Diagnostic
Keywords: Irritable Bowel Syndrome; Elimination diet; Food allergies