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IgG-Guided Elimination Diet Promising for Irritable Bowel Syndrome

— Improved global endpoints compared with sham diet, says Anthony Lembo, MD

Ƶ MedicalToday

Patients with irritable bowel syndrome (IBS) could benefit from eliminating foods found to be problematic with a novel diagnostic tool, according to presented at the American College of Gastroenterology annual meeting.

In this exclusive Ƶ video, co-primary study investigator , director of the GI Motility and Functional Bowel Disorders Program at Beth Israel Deaconess Medical Center in Boston, discusses the results of the study.

Following is a transcript of his remarks:

We know that diet is a big factor in contributing to patients' symptoms in IBS, and there are a number of diets that have been studied -- particularly the low-FODMAP [fermentable oligosaccharides, disaccharides, monosaccharides and polyols] diet. However that could be a very cumbersome and difficult diet to follow. In this study, we looked at the role of IgG [immunoglobulin G] antibodies in identifying food sensitivities in patients with IBS.

This was a unique IgG panel that was determined in a very rigorous, scientific way, starting with 90 different foods in patients with IBS and healthy controls, and then including only the foods where there was a difference between IBS and healthy controls at the 0.05 level. Ultimately, this led to 24 problematic foods that were identified, and this was subsequently selected down to 18 problematic foods based on the prevalence of which people ate those foods in IBS.

So what we did in this study is we randomized 238 patients with IBS to either receive the true diet, which I'll tell you in a minute, or a sham diet. Patients had to have at least an average pain score of greater than equal to 3, no more than 7.5 on a 0-to-10 scale. Patients were randomized to include the diet for a total of 8 weeks. We took all subtypes of IBS, and they were fairly well distributed between the IBS-C [IBS with constipation], -D [IBS with diarrhea], and -M [IBS with mixed bowel habits]. The majority of patients were female.

So on average, patients had between four and five positive foods in the testing in the study. And the sham diet group, who also would have positive foods, but what they did was they had foods that they were not positive to, but were in a similar class as a cohort patient that was in the true diet. So, for example, if a diet in the true diet was low in FODMAPs or low in fructans, then we would have a separate patient in the sham diet that was also low in the fructans. So we tried to keep out any bias with this.

So again, as I said, it was 8 weeks and during that time we measured abdominal pain on a 0-to-10 scale and bloating also on a 0-to-10 scale. And these were our primary endpoints.

And for all comers, we had a strong trend for both pain and bloating at the P value of 0.07 for pain and 0.08 for bloating. However, for the global endpoints which we measured, there was a statistically significant trend for all comers. We used something called the SGA [Subject Global Assessment of Relief] and GIS [Global Improvement Scale], which are commonly used in IBS trials. We also measured IBS-SS, which is a severity score -- that did not meet statistical significance, but also had a trend at 0.11.

We also looked at responder rates for abdominal pain, and the most common one used in drug trials is a 30% improvement in pain. We did show an overall statistically significant difference in all subjects.

When we looked at the subgroups, we saw the strongest differences between IBS-C and IBS-M. And there we saw many of the endpoints were statistically significant -- less so for IBS-D.

And you can see several figures where we picked the key endpoints, the ones that showed the most significant difference. And you can look at those figures and that goes from Figure 1 to Figure 7. Those are the key endpoints that we thought were significant, worth showing.

So these results suggest that an IgG-based elimination diet using a novel proprietary diagnostic panel with 18 specific foods can help guide therapy and may offer benefit to some patients with IBS. And again, the results of this study warrant further study. This was a multicenter trial including three to four, I think four centers. But we would need to repeat this.

And in conclusion, this novel IgG-based elimination diet in comparison to sham diet, significantly improved global endpoints and showed trends towards improvement in the abdominal pain and bloating for all-comers. And again, and we also saw for the subsets being more significant for IBS-M and IBS-C.

Thank you very much for your attention.

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    Greg Laub is the Senior Director of Video and currently leads the video and podcast production teams.