P0558 - Breath Test Responses to Key FODMAP Substrates in a Symptomatic Cohort

Prashant Singh, MD¹, Aonghus Shortt, PhD², Claire Shortt, PhD², Barry McBride, MSc², Robert Burke, MSc², William Chey, MD, FACG³
1University of Michigan Medical School, Ann Arbor, MI; 2FoodMarble, Dublin, Dublin, Ireland; 3University of Michigan Health, Ann Arbor, MI

Introduction: A low FODMAP-diet (LFD) is an effective strategy for managing symptoms in patients with IBS. However, the initial restriction phase can be challenging. Standardized carbohydrate intolerance breath tests might be useful in predicting more personalized LFD restriction. This study aims to evaluate the breath test responses to following substrates: fructose (F), inulin (I), lactose (L), and sorbitol (S).

Methods: 734 self-selected participants (48±13 years, 56% female, 24.3 ± 4 kg/m² BMI) performed breath tests at home in a fasted state using a personal app-connected breath analyzer (AIRE®, FoodMarble, Ireland). After recording a baseline breath reading, they ingested a substrate (fructose 25 g, inulin 10 g, lactose 25 g or sorbitol 10 g) and recorded breath readings every 15 min for 3 hrs (every 30 min for inulin). H₂ positivity (a rise of ≥ 20 ppm above baseline), and CH₄ positivity (a rise of ≥ 10 ppm above baseline) are pooled for this analysis. Participants completed all four FODMAP tests and reported their most bothersome symptoms prior to testing.

Results: The average number of positive tests was 1.79 per participant, with 9% (65) positive in all 4 tests and 17% (126) negative in all 4 tests. The most common co-occurrences of positivity were S+I+F (11%), S+I+F+L (all) (9%), S+F (8%), S+I (7%), with 14% intolerant to sorbitol only (Figure 1). Where only a single FODMAP was implicated (Figure 2), the fructose-only group (3%) reported the highest frequency of abdominal pain, belching, nausea and heartburn at baseline, whereas the inulin- and sorbitol-only groups (4%, 14%) reported similar symptom frequency at baseline, with flatulence, fatigue and constipation being most notable for these two groups. The lactose-only group (4%) reported lower heartburn than the other groups.

Discussion: The majority of participants were breath-test positive for an average of two FODMAP groups, with sorbitol being the substrate they were most commonly positive for. Fructose positivity is more associated with upper-GI symptoms, possibly due to higher osmotic load in the proximal small intestine. Conversely, inulin and sorbitol-related symptom profiles may be more indicative of colonic fermentation and higher overall gas production. More research is needed to better understand the role of baseline symptom profiles and breath test responses in the personalization of FODMAP restriction.


Figure: Common combinations and associated frequencies of positive tests (N=734).


Figure: Commonly reported symptoms prior to testing for each substrate-positive group. Left shows participants positive to one FODMAP only, while right shows the participants in each of the 4 most frequent positivity combinations. Fructose-positive individuals reported more upper-GI related symptoms while Sorbitol- and Inulin-positive individuals reported more lower-GI related symptoms.

Disclosures:
Prashant Singh: Uptodate – Royalties.
Aonghus Shortt: FoodMarble Digestive Health – Owner/Ownership Interest.
Claire Shortt: FoodMarble Digestive Health – Employee.
Barry McBride: FoodMarble Digestive Health – Employee.
Robert Burke: FoodMarble Digestive Health – Employee.
William Chey: Ardelyx – Consultant. Atmo – Consultant. Biomerica – Consultant. Commonwealth Diagnostics International – Grant/Research Support. Coprata – Stock Options. Dieta – Stock Options. Digital Manometry – Intellectual Property/Patents. Evinature – Stock Options. FoodMarble – Stock Options. Gemelli – Consultant. Kiwi BioScience – Stock Options. Modify Health – Stock Options. My Nutrition Health – Intellectual Property/Patents. Phathom – Consultant. Rectal Expulsion Device – Intellectual Property/Patents. Redhill – Consultant. Salix – Consultant, Grant/Research Support. Takeda – Consultant. Vibrant – Consultant.

Prashant Singh, MD¹, Aonghus Shortt, PhD², Claire Shortt, PhD², Barry McBride, MSc², Robert Burke, MSc², William Chey, MD, FACG³. P0558 - Breath Test Responses to Key FODMAP Substrates in a Symptomatic Cohort, ACG 2025 Annual Scientific Meeting Abstracts. Phoenix, AZ: American College of Gastroenterology.