Introduction

Irritable Bowel Syndrome (IBS) affects approximately 10% to 15% of adults in the United States, manifesting as abdominal pain, cramps, and altered bowel habits. Identifying specific dietary triggers has long been a challenge for both patients and healthcare providers. However, recent research from Michigan Medicine and Cleveland Clinic introduces a promising solution: a blood test that guides personalized dietary therapy for IBS patients.

The Study: A Closer Look

In a multicenter, randomized, double-blind, sham-controlled trial, 238 IBS patients across eight U.S. academic centers were assessed using a proprietary assay (inFoods IBS, Biomerica). This test measures Immunoglobulin G (IgG) antibody levels against 18 potential food triggers, identifying foods that elicit an above-normal IgG response—a marker of inflammation in IBS patients.

Participants were divided into two groups:

1. Personalized Diet Group: Eliminated foods that tested positive for elevated IgG antibodies.
2. Sham Diet Group: Followed a diet eliminating foods similar to, but not the same as, those identified in the test. For example, if a patient had a heightened IgG response to walnuts, they were instructed to eliminate almonds instead.

William Chey, M.D., Chief of Gastroenterology & Hepatology at the University of Michigan and an investigator in the study, said: “This IBS-specific, IgG antibody test requires additional validation but could move us one step closer to a ‘precision nutrition’ approach, in which providers can offer personalized dietary recommendations to each patient with IBS.”

Results: Significant Symptom Reduction

The findings, published in Gastroenterology, revealed that 59.6% of participants adhering to the personalized diet achieved a clinically significant reduction in abdominal pain, compared to 42.2% in the sham diet group. Notably, the benefits were most pronounced in patients with IBS characterized by constipation (67.1% vs. 35.8%) or a mix of constipation and diarrhea (66% vs. 29.5%).

Dr. Prashant Singh, the lead author and a gastroenterologist at Michigan Medicine, noted, "Patients had done all sorts of IgG antibody testing before, and it wasn’t very reliable. This latest test is supported by science. I can refer patients to this IBS-specific antibody testing, after explaining the science and the limitations of the study."

Implications: A Step Toward Precision Medicine

Traditional elimination diets for IBS, such as the low FODMAP diet, often require patients to restrict a wide range of foods, making adherence challenging. This IBS-specific IgG-based test offers a more targeted approach, allowing patients to eliminate only the specific trigger foods identified by the assay.

“Our diets are complex and identifying dietary triggers can be difficult.  This IBS-specific IgG test can help patients who suffer from IBS identify specific dietary triggers,” said Anthony Lembo, M.D.

Conclusion

This innovative blood test represents a significant advancement in IBS management, providing a scientifically supported method to identify individual dietary triggers. By tailoring dietary interventions based on specific IgG antibody responses, healthcare providers can offer more effective and personalized treatment plans, potentially improving the quality of life for many IBS sufferers.

MEDIA CONTACTS:

Michigan Medicine: Sam Page, sam.page@med.umich.edu, 734-764-2220

Cleveland Clinic: Caroline Auger, augerc@ccf.org, 216-296-6012

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About Cleveland Clinic

Cleveland Clinic is a nonprofit multispecialty academic medical center that integrates clinical and hospital care with research and education. Located in Cleveland, Ohio, it was founded in 1921 by four renowned physicians with a vision of providing outstanding patient care based upon the principles of cooperation, compassion and innovation. Cleveland Clinic has pioneered many medical breakthroughs, including coronary artery bypass surgery and the first face transplant in the United States. Cleveland Clinic is consistently recognized in the U.S. and throughout the world for its expertise and care. Among Cleveland Clinic’s 81,000 employees worldwide are more than 5,743 salaried physicians and researchers, and 20,160 registered nurses and advanced practice providers, representing140 medical specialties and subspecialties. Cleveland Clinic is a 6,690-bed health system that includes a 173-acre main campus near downtown Cleveland, 23 hospitals, 276 outpatient facilities, including locations in northeast Ohio; Florida; Las Vegas, Nevada; Toronto, Canada; Abu Dhabi, UAE; and London, England. In 2023, there were 13.7 million outpatient encounters, 323,000 hospital admissions and observations, and 301,000 surgeries and procedures throughout Cleveland Clinic’s health system. Patients came for treatment from every state and 132 countries. Visit us at clevelandclinic.org. Follow us attwitter.com/CleClinicNews. News and resources available at newsroom.clevelandclinic.org.

Editor’s Note: Cleveland Clinic News Service is available to provide broadcast-quality interviews and B-roll upon request.

About Michigan Medicine and University of Michigan Health

At Michigan Medicine, we advance health to serve Michigan and the world. We pursue excellence every day in our 11 hospitals and hundreds of clinics statewide, as well as educate the next generation of physicians, health professionals and scientists in our U-M Medical School.

Michigan Medicine includes U-M Medical School and University of Michigan Health, which includes the C.S. Mott Children’s Hospital, Von Voigtlander Women’s Hospital, University Hospital, the Frankel Cardiovascular Center, Kellogg Eye Center, University of Michigan Health-West, University of Michigan Health-Sparrow and the Rogel Cancer Center. The U-M Medical School is one of the nation's biomedical research powerhouses, with total research awards of more than $777 million.

More information is available at www.michiganmedicine.org

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