Anthony Lembo, MD, FACG

IgG-based elimination diets using a novel diagnostic tool to guide therapy may be beneficial to some patients with irritable bowel syndrome (IBS), according to Anthony Lembo, MD, FACG.

Previous studies show that diet modification can improve symptoms in patients with IBS, he explained. “Food intolerances/sensitivities are common in patients with IBS, but outcomes following self-directed elimination diets are poor,” he wrote. “The role of IgG antibodies in identifying patients with food sensitivities is controversial.”

Dr. Lembo and colleagues sought to assess the utility of a novel, proprietary, IgG-based elimination diet to improve symptoms in patients with IBS. The study’s findings were presented at the recent American College of Gastroenterology (ACG) 2022 annual meeting in Charlotte, North Carolina, held in person and virtually.

Assessments Included Bloating, Bowel Habits, & Abdominal Pain Intensity

A total of 223 patients with IBS from six centers met eligibility for the double-blind, placebo-controlled diet treatment phase. For 8 weeks, they were randomly assigned to a treatment diet group or a sham diet group. Patients in the treatment diet arm were instructed to eliminate foods to which they tested positive, while those in the sham diet arm were told to forego foods to which they tested negative. The sham diet arm was balanced to the active diet arm based on the number of foods excluded and self-reported incidence of consuming a specific food.

Daily assessments included bloating, bowel habits, and abdominal pain intensity (API), as well as weekly assessments for Subject Global Assessment of Relief (SGA), IBS Adequate Relief (AR), and Global Improvement Scale (GIS). For all IBS patients and for non-IBS-D patients, linear mixed and logistic regression modeling of endpoints in the intent-to-treat population was presented.

The most common foods removed from the diets, Dr. Lembo noted, were corn, chicken, wheat, eggs, milk, oats, onion, soybeans, and walnuts.

Compared with patients in the sham diet arm, patients in the treatment diet arm showed a greater decrease in IBS-API and IBS-Bloating scores from baseline. However, GIS and SGA did show meaningful improvement (GIS, P=0.0302; SGA, P=0.0093). Non-IBS-D patients (N=149) showed the largest decrease from baseline (IBS-API, P=0.0139; IBS-Bloating, P=0.0214), as well as for global measures (GIS, P=0.0020; SGA, P=0.0010).

Dr. Lembo and colleagues would like to see a repeat study done with a larger cohort of patents with IBS. In addition, “the long-term impact of eliminating specific foods needs to be explored further,” the study authors wrote.