Charlotte, NC – Some people have irritable bowel syndrome New research shows that IBS could benefit from eliminating foods found to be problematic with a new diagnostic tool.
The tool identifies increases in immunoglobulin G (IgG) antibody levels caused by food allergies, and indicates offenders that should be eliminated from the diets of individual patients with irritable bowel syndrome. Elimination of problem foods led to a significant difference in global measures of improvement and symptom relief, according to a prospective, multicenter, double-blind study.
The results of the study were presented at the American College of Gastroenterology (ACG) 2022 annual meeting in Charlotte, North Carolina, which is being held in person and virtually.
Whether IgG-based diets help IBS patients is highly controversial, although more than three-quarters of patients associate their symptoms with a meal, said study co-author William Chey, MD, professor of medicine and director of the GI Physiology Laboratory at the University of Michigan in Ann Arbor, said Medscape Medical News.
“This is one of the largest and most rigorous randomized controlled trials ever conducted on an IgG-based exclusion diet,” Chi said.
The researchers selected the foods most commonly found to cause elevated levels of IgG antibodies in previous IBS research.
Milk, corn, eggs, oats, onions, soybeans, walnuts, wheat, and chicken were most often removed from diets, said Anthony Limbaugh, MD, the other researcher on the joint study, a gastroenterologist at Beth Israel Deaconess Medical Center and professor of medicine at Beth Israel Deaconess Medical Center. . Harvard Medical School in Boston, Massachusetts.
Although food sensitivities are common among people with irritable bowel syndrome, “outcomes after following a self-directed elimination diet are poor,” the researchers note.
To determine whether a new, proprietary IgG panel (InFoods, Biomerica) could help improve IBS symptoms, Lembo, Chey and colleagues studied 223 adults with IBS enrolled in six centers.
After a 2-week baseline, those who tested positive for one or more food allergies and who had a mean daily abdominal pain severity score of 3 to 7.5 (on a scale of 1 to 10) were evaluated.
Participants were randomly assigned to a therapeutic diet group or a dummy diet group for 8 weeks. People in the diet group were instructed to eliminate foods that they tested were allergic to, while the placebo group eliminated foods they tested negative. The groups were balanced in terms of the number of foods that were excluded.
People in both groups reported daily bowel habits, bloating, and abdominal pain intensity. They also completed weekly assessments using the appropriate IBS relief tools, the Subject Global Relief Assessment (SGA), and the Global Improvement Scale (GIS).
Compared with baseline, the treatment group showed a greater reduction in abdominal pain intensity (IBS-API) and bloating outcome compared to the placebo group, according to an intent-to-treat analysis at 8 weeks. However, these changes do not meet the statistical significance.
However, participants in the treatment group experienced significant improvements over SGA (s <.001) and GIS (s <.001).
One subgroup of patients, 149 people who do not have irritable bowel syndrome Diarrheashowed the greatest reduction in symptoms from baseline on IBS-API (s = 0.014) and IBS-Bloating (s = 0.021) measures. They also reported the best improvements to GIS (s <.001) and SGA (s <.001).
No significant adverse events were observed during the study.
The study provides “reliable evidence that this IgG-exclusion diet provides a benefit for general symptoms in some patients with IBS — and this benefit appears to be stronger in patients with non-diarrheal IBS,” Chi says.
The researchers note that the findings should help guide other studies.
“We need to repeat this study in a larger group of IBS patients,” Limbaugh said. “The long-term effect of cutting out certain foods also needs to be explored further.”
Prior to this study, data indicated that modifying the diet based on a patient’s IgG antibody response to foods could alleviate IBS symptoms, said Lin Zhang, MD, Medscape Medical Newswhen asked for comment.
Zhang, MD, vice president of gastroenterology at UCLA Health in Los Angeles, California added.
“It’s a bit unexpected to see a greater benefit in patients without IBS,” she said. “I was expecting more benefit in IBS-D.”
Zhang also noted that more studies are needed.
For more information, see “AGA clinical practice update on the role of diet in irritable bowel syndrome: an expert review,” authored by Chey, Chang and colleagues.
The study was independently supported. Chi reports as a consultant to Biomerica, as well as AbbVie, Allakos, Alnylam, Arena Pharmaceuticals, Commonwealth Diagnostics International, Gemelli Biotech, Ironwood Pharmaceuticals, ISOTrive, Nestle, Phathom Pharmaceuticals, Progenity and Redhill, and Urovant Sciences, a Vibrant Pharma, such as in addition to being a consultant and receiving grant/research support from QOL Medical and Salix Pharmaceuticals, and owning stock options in GI OnDEMAND, ISOThrive, and Modify Health. Lembo reported being an advisor to Alkermes, Arena, Bayer, Gemelli Biotech, Ironwood, OrphoMed, Salix, Shire, Takeda Pharmaceuticals and Vibrant, as well as being an advisor to Vibrant and owning stock options in Bristol-Myers Squibb and Johnson & Johnson. Chang has You mentioned no related financial relationships.
ACG 2022. Abstract No. B0274. ACG Presidential Poster Award. It was introduced on October 24, 2022.
Damian McNamara is a Miami-based journalist. It covers a wide range of medical specialties, including infectious diseases, gastroenterology, and critical care. Follow Damien on Twitter: Tweet embed.
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