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An irritable bowel syndrome (IBS) elimination diet based on a novel IBS–specific, immunoglobulin G (IgG) was superior to a sham diet for abdominal pain, an 8-center, randomized double-blind controlled trial found.
While elimination diets can provide a personalized approach to dietary therapy, existing studies have had serious methodological issues, noted lead author Prashant Singh, MBBS, of the Division of Gastroenterology and Hepatology, Department of Internal Medicine, Michigan Medicine, Ann Arbor, Mich., and colleagues in Gastroenterology.
For example, previous studies on IgG-based diets used assays developed without determining IBS trigger foods or establishing a 95% confidence interval–based cutoff using a healthy control comparison group.
Study Details
From June 2018 to December 2021, 238 IBS patients testing positive for at least one food on 18-food IgG ELISA (enzyme-linked immunosorbent assay) testing and an average daily abdominal pain intensity score of 3.0 to 7.5 on an 11.0-point scale during a 2-week run-in period were randomized for 8 weeks to an experimental antibody-guided diet or to a sham diet. The primary outcome was a 30% decrease in abdominal pain intensity (API) for 2 of the last 4 weeks of treatment.
The overall study population had a mean age of about 40 years, and more than three-quarters were female. The 3 IBS types – constipation-predominant (IBS-C), diarrhea-predominant (IBS-D), and mixed bowel habits-predominant (IBS-M) – accounted for about a third each in both arms.
The experimental diet eliminated foods based on a positive ELISA result. Its sham counterpart had the same number of foods removed as the number of positive-testing food sensitivities, but the foods eliminated in the sham diet had tested negative on the IgG assay.
Participants reported daily abdominal pain intensity, bloating, and stool consistency, and frequency. They also reported dietary compliance and daily medication use.
Of the 238 randomized adults, 223 were included in the modified intention-to-treat analysis. A significantly greater proportion of subjects in the experimental group met the primary outcome than those in the sham group: 59.6% vs 42.1%, P = .02). “This highlights the potential effectiveness of a personalized elimination diet based on a novel IBS-specific IgG assay,” the authors wrote.
Symptom improvement between arms began to separate out at around 2 weeks, suggesting the effect of the experimental diet was relatively rapid in onset, and continued for at least 8 weeks. The durability of response, however, needs to be assessed in future studies “and it is unclear if there is a role for repeat IgG testing to monitor treatment response,” the authors wrote.
Subgroup analysis revealed that a higher proportion of those with IBS-C and IBS-M in the experimental diet group met the primary endpoint vs the sham group: 67.1% vs 35.8% and 66% vs 29.5%, respectively.
Interestingly, more patients in the experimental arm were noncompliant with their diet. “It is possible that subjects found the experimental diet more difficult to comply with compared with the sham diet or that because the experimental diet was more likely to improve symptoms, dietary indiscretion may have been more common in this group (a phenomenon seen with other elimination diets such as gluten-free diet in celiac disease),” the authors wrote.
Adverse events, deemed unrelated to either regimen, were 3 in the experimental arm vs 8 in the sham arm, which had 2 urinary tract infections.
The authors called for a larger, adequately powered study to assess the efficacy of an elimination diet based on this novel immunoglobulin G assay in patients with IBS-C and IBS-M. Future studies should perform detailed adherence assessments using food diaries.
“Mechanisms of how immunoglobulin G-antibody response to food antigen generates symptoms in irritable bowel syndrome are not well understood. Delineating this might provide new insights into food-related irritable bowel syndrome pathophysiology,” they concluded.
This study was funded by Biomerica Inc.
Symptoms in most people with irritable bowel syndrome (IBS) are perceived to be closely linked to diet. The low FODMAP diet has been pivotal for the treatment of IBS, and a range of other diet approaches are now on the research horizon.
Whilst IgE-mediated allergy is relatively rare, there has been research suggesting a role of IgG-mediated food sensitivity in causing symptoms in IBS, although the role of IgG testing and dietary elimination has been controversial. This study from Singh and colleagues suggests an IgG-based elimination diet could improve abdominal pain and global symptoms in two thirds of people with Rome IV IBS. Critically, the study is one of the largest so far and provides the most robust and detailed description of the trial diets to date.
The potential of a new diet approach is extremely appealing, especially as the low FODMAP diet is not universally effective. However, there is still some work to be done to transition the IgG-based elimination diet into guidelines and routine practice. Notably, some common foods restricted in IgG-based elimination diets are also high in FODMAPs leaving questions about the true driver of symptom benefit. Should convincing mechanistic studies and further additional RCT data validate these findings, this could present a major step forward for personalised nutrition in IBS.
Heidi Staudacher, PhD, is associate professor in the School of Translational Medicine, Monash University, Melbourne, Australia. She declared no conflicts of interest.
Symptoms in most people with irritable bowel syndrome (IBS) are perceived to be closely linked to diet. The low FODMAP diet has been pivotal for the treatment of IBS, and a range of other diet approaches are now on the research horizon.
Whilst IgE-mediated allergy is relatively rare, there has been research suggesting a role of IgG-mediated food sensitivity in causing symptoms in IBS, although the role of IgG testing and dietary elimination has been controversial. This study from Singh and colleagues suggests an IgG-based elimination diet could improve abdominal pain and global symptoms in two thirds of people with Rome IV IBS. Critically, the study is one of the largest so far and provides the most robust and detailed description of the trial diets to date.
The potential of a new diet approach is extremely appealing, especially as the low FODMAP diet is not universally effective. However, there is still some work to be done to transition the IgG-based elimination diet into guidelines and routine practice. Notably, some common foods restricted in IgG-based elimination diets are also high in FODMAPs leaving questions about the true driver of symptom benefit. Should convincing mechanistic studies and further additional RCT data validate these findings, this could present a major step forward for personalised nutrition in IBS.
Heidi Staudacher, PhD, is associate professor in the School of Translational Medicine, Monash University, Melbourne, Australia. She declared no conflicts of interest.
Symptoms in most people with irritable bowel syndrome (IBS) are perceived to be closely linked to diet. The low FODMAP diet has been pivotal for the treatment of IBS, and a range of other diet approaches are now on the research horizon.
Whilst IgE-mediated allergy is relatively rare, there has been research suggesting a role of IgG-mediated food sensitivity in causing symptoms in IBS, although the role of IgG testing and dietary elimination has been controversial. This study from Singh and colleagues suggests an IgG-based elimination diet could improve abdominal pain and global symptoms in two thirds of people with Rome IV IBS. Critically, the study is one of the largest so far and provides the most robust and detailed description of the trial diets to date.
The potential of a new diet approach is extremely appealing, especially as the low FODMAP diet is not universally effective. However, there is still some work to be done to transition the IgG-based elimination diet into guidelines and routine practice. Notably, some common foods restricted in IgG-based elimination diets are also high in FODMAPs leaving questions about the true driver of symptom benefit. Should convincing mechanistic studies and further additional RCT data validate these findings, this could present a major step forward for personalised nutrition in IBS.
Heidi Staudacher, PhD, is associate professor in the School of Translational Medicine, Monash University, Melbourne, Australia. She declared no conflicts of interest.
An irritable bowel syndrome (IBS) elimination diet based on a novel IBS–specific, immunoglobulin G (IgG) was superior to a sham diet for abdominal pain, an 8-center, randomized double-blind controlled trial found.
While elimination diets can provide a personalized approach to dietary therapy, existing studies have had serious methodological issues, noted lead author Prashant Singh, MBBS, of the Division of Gastroenterology and Hepatology, Department of Internal Medicine, Michigan Medicine, Ann Arbor, Mich., and colleagues in Gastroenterology.
For example, previous studies on IgG-based diets used assays developed without determining IBS trigger foods or establishing a 95% confidence interval–based cutoff using a healthy control comparison group.
Study Details
From June 2018 to December 2021, 238 IBS patients testing positive for at least one food on 18-food IgG ELISA (enzyme-linked immunosorbent assay) testing and an average daily abdominal pain intensity score of 3.0 to 7.5 on an 11.0-point scale during a 2-week run-in period were randomized for 8 weeks to an experimental antibody-guided diet or to a sham diet. The primary outcome was a 30% decrease in abdominal pain intensity (API) for 2 of the last 4 weeks of treatment.
The overall study population had a mean age of about 40 years, and more than three-quarters were female. The 3 IBS types – constipation-predominant (IBS-C), diarrhea-predominant (IBS-D), and mixed bowel habits-predominant (IBS-M) – accounted for about a third each in both arms.
The experimental diet eliminated foods based on a positive ELISA result. Its sham counterpart had the same number of foods removed as the number of positive-testing food sensitivities, but the foods eliminated in the sham diet had tested negative on the IgG assay.
Participants reported daily abdominal pain intensity, bloating, and stool consistency, and frequency. They also reported dietary compliance and daily medication use.
Of the 238 randomized adults, 223 were included in the modified intention-to-treat analysis. A significantly greater proportion of subjects in the experimental group met the primary outcome than those in the sham group: 59.6% vs 42.1%, P = .02). “This highlights the potential effectiveness of a personalized elimination diet based on a novel IBS-specific IgG assay,” the authors wrote.
Symptom improvement between arms began to separate out at around 2 weeks, suggesting the effect of the experimental diet was relatively rapid in onset, and continued for at least 8 weeks. The durability of response, however, needs to be assessed in future studies “and it is unclear if there is a role for repeat IgG testing to monitor treatment response,” the authors wrote.
Subgroup analysis revealed that a higher proportion of those with IBS-C and IBS-M in the experimental diet group met the primary endpoint vs the sham group: 67.1% vs 35.8% and 66% vs 29.5%, respectively.
Interestingly, more patients in the experimental arm were noncompliant with their diet. “It is possible that subjects found the experimental diet more difficult to comply with compared with the sham diet or that because the experimental diet was more likely to improve symptoms, dietary indiscretion may have been more common in this group (a phenomenon seen with other elimination diets such as gluten-free diet in celiac disease),” the authors wrote.
Adverse events, deemed unrelated to either regimen, were 3 in the experimental arm vs 8 in the sham arm, which had 2 urinary tract infections.
The authors called for a larger, adequately powered study to assess the efficacy of an elimination diet based on this novel immunoglobulin G assay in patients with IBS-C and IBS-M. Future studies should perform detailed adherence assessments using food diaries.
“Mechanisms of how immunoglobulin G-antibody response to food antigen generates symptoms in irritable bowel syndrome are not well understood. Delineating this might provide new insights into food-related irritable bowel syndrome pathophysiology,” they concluded.
This study was funded by Biomerica Inc.
An irritable bowel syndrome (IBS) elimination diet based on a novel IBS–specific, immunoglobulin G (IgG) was superior to a sham diet for abdominal pain, an 8-center, randomized double-blind controlled trial found.
While elimination diets can provide a personalized approach to dietary therapy, existing studies have had serious methodological issues, noted lead author Prashant Singh, MBBS, of the Division of Gastroenterology and Hepatology, Department of Internal Medicine, Michigan Medicine, Ann Arbor, Mich., and colleagues in Gastroenterology.
For example, previous studies on IgG-based diets used assays developed without determining IBS trigger foods or establishing a 95% confidence interval–based cutoff using a healthy control comparison group.
Study Details
From June 2018 to December 2021, 238 IBS patients testing positive for at least one food on 18-food IgG ELISA (enzyme-linked immunosorbent assay) testing and an average daily abdominal pain intensity score of 3.0 to 7.5 on an 11.0-point scale during a 2-week run-in period were randomized for 8 weeks to an experimental antibody-guided diet or to a sham diet. The primary outcome was a 30% decrease in abdominal pain intensity (API) for 2 of the last 4 weeks of treatment.
The overall study population had a mean age of about 40 years, and more than three-quarters were female. The 3 IBS types – constipation-predominant (IBS-C), diarrhea-predominant (IBS-D), and mixed bowel habits-predominant (IBS-M) – accounted for about a third each in both arms.
The experimental diet eliminated foods based on a positive ELISA result. Its sham counterpart had the same number of foods removed as the number of positive-testing food sensitivities, but the foods eliminated in the sham diet had tested negative on the IgG assay.
Participants reported daily abdominal pain intensity, bloating, and stool consistency, and frequency. They also reported dietary compliance and daily medication use.
Of the 238 randomized adults, 223 were included in the modified intention-to-treat analysis. A significantly greater proportion of subjects in the experimental group met the primary outcome than those in the sham group: 59.6% vs 42.1%, P = .02). “This highlights the potential effectiveness of a personalized elimination diet based on a novel IBS-specific IgG assay,” the authors wrote.
Symptom improvement between arms began to separate out at around 2 weeks, suggesting the effect of the experimental diet was relatively rapid in onset, and continued for at least 8 weeks. The durability of response, however, needs to be assessed in future studies “and it is unclear if there is a role for repeat IgG testing to monitor treatment response,” the authors wrote.
Subgroup analysis revealed that a higher proportion of those with IBS-C and IBS-M in the experimental diet group met the primary endpoint vs the sham group: 67.1% vs 35.8% and 66% vs 29.5%, respectively.
Interestingly, more patients in the experimental arm were noncompliant with their diet. “It is possible that subjects found the experimental diet more difficult to comply with compared with the sham diet or that because the experimental diet was more likely to improve symptoms, dietary indiscretion may have been more common in this group (a phenomenon seen with other elimination diets such as gluten-free diet in celiac disease),” the authors wrote.
Adverse events, deemed unrelated to either regimen, were 3 in the experimental arm vs 8 in the sham arm, which had 2 urinary tract infections.
The authors called for a larger, adequately powered study to assess the efficacy of an elimination diet based on this novel immunoglobulin G assay in patients with IBS-C and IBS-M. Future studies should perform detailed adherence assessments using food diaries.
“Mechanisms of how immunoglobulin G-antibody response to food antigen generates symptoms in irritable bowel syndrome are not well understood. Delineating this might provide new insights into food-related irritable bowel syndrome pathophysiology,” they concluded.
This study was funded by Biomerica Inc.
FROM GASTROENTEROLOGY