J Neurogastroenterol Motil 2024; 30(3): 379-380  https://doi.org/10.5056/jnm24009
Predicting Response to Low Fermentable Oligo-, Di-, Mono-saccharides, and Polyols Diet in Patients With Abdominal Bloating Using Hydrogen Methane Breath Test: Is a Spot Sample Enough?
Uday C Ghoshal,1,2* Uzma Mustafa,1 Subhra K Mukhopadhyay,1 and Mahesh K Goenka1
1Institute of Gastrosciences and Liver Transplantation, Apollo Multispeciality Hospitals, Kolkata, India; and 2Department of Microbiology, The University of Burdwan, Burdwan, West Bengal, India
Published online: July 30, 2024
© The Korean Society of Neurogastroenterology and Motility. All rights reserved.

cc This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
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TO THE EDITOR: Somvanapanich et al1 showed that a 2-hour post-lunch spot hydrogen (H2) and methane (CH4) breath test predicted response to low fermentable oligo-, di-, mono-saccharides, and polyols (FODMAP) diet. While we acknowledge its significance, we have a few comments.

In this study, the spot breath test was performed after usual non-standardized lunch.1 The variable amount of “FODMAPs” in the non-uniform meals might influence the diagnostic accuracy of the test. Also, the comparison of outcomes across studies may be difficult.

The FODMAP content in a meal does not depend only on food types but also on serving sizes (https://www.monashfodmap.com/ibs-central/i-have-ibs/get-the-app/). A specific food may be classified as low-FODMAP at a particular serving size, moderate-FODMAP at a larger size, and high-FODMAP at a greater size.

About 40% of gastric emptying occurs during the initial 2 hours after meal and 90% by 4 hours.2 Fermentation of FODMAP largely occurs in distal gut.3 In our recent study on FODMAP-meal challenge test, we observed that rise in breath H2 was most prominent after the first 4 hours of ingestion of a standardized high FODMAP meal.4 Somvanapanich et al1 claimed that they replicated their previous protocol wherein, rise in breath H2 was not observed after breakfast until 2 hours post-lunch.5 However, it raises a question whether 2-hour post-lunch rise is exclusively attributed to lunch and not influenced by the breakfast. Moreover, assuming that a small portion of lunch meal reached the distal small bowel 2-hour post-lunch, it could cause “FODMAP stacking effect” to the breakfast meal.1 “FODMAP stacking effect” refers to adding up FODMAPs in the gut before manifesting into symptoms.

Interestingly, 6/21 responders (28.57%) had constipation-predominant irritable bowel syndrome (IBS-C).1 Most studies showing benefit of low-FODMAP diet included non-IBS-C patients.4

The major food items consumed in this study were animal proteins and rice, which are low in FODMAP though high FODMAP additives might be used in preparation.1 High-protein diets might shift carbohydrate to protein fermentation by gut bacteria.6-8 A possibility of high FODMAP food additives or protein foods might cause the observed rise in breath gases.

The sensitivity observed by Somvanapanich et al1 (66.7%) is lower than our study (78%).4 The above-mentioned factors might explain the difference in sensitivity in these 2 studies.1,4 We believe that studying breath H2 over a longer duration along with symptoms generation is expected to predict microbial metabolic index in the gut lumen and visceral hypersensitivity to predict response to a low-FODMAP meal as reported by us recently. 4

Acknowledgements

Uzma Mustafa thanks GastroLab India Pvt. Ltd. for supporting her.

Financial support

None.

Conflicts of interest

Uday C Ghoshal have patent application for BreathCalc and FODMAP meal challenge test. None of the other authors declare any conflict of interest.

Author contributions

Uday C Ghoshal conceptualized, reviewed literature, and contributed to drafting and editing the manuscript; Uzma Mustafa reviewed literature and helped to write the first draft; Subhra K Mukhopadhyay and Mahesh K Goenka provided critical input while writing and edited the paper. All the authors read the final version of the paper.

References
  1. Somvanapanich P, Pitisuttithum P, Sirimongkolkasem J, et al. Spot hydrogen breath test for predicting response to low fermentable oligo-, di-, mono-saccharides, and polyols dietary advice in patients with bloating. J Neurogastroenterol Motil 2023;29:513-519.
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  2. Tougas G, Eaker EY, Abell TL, et al. Assessment of gastric emptying using a low fat meal: establishment of international control values. Am J Gastroenterol 2000;95:1456-1462.
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  3. Barrett JS, Gearry RB, Muir JG, et al. Dietary poorly absorbed, short-chain carbohydrates increase delivery of water and fermentable substrates to the proximal colon. Aliment Pharmacol Ther 2010;31:874-882.
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  4. Ghoshal UC, Mustafa U, Mukhopadhyay SK. FODMAP meal challenge test: a novel investigation to predict response to low-FODMAP diet in non-constipating irritable bowel syndrome. J Gastroenterol Hepatol 2024;39:297-204.
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  5. Linlawan S, Patcharatrakul T, Somlaw N, Gonlachanvit S. Effect of rice, wheat, and mung bean ingestion on intestinal gas production and postprandial gastrointestinal symptoms in non-constipation irritable bowel syndrome patients. Nutrients 2019;11:2061.
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  6. Gilbert MS, Ijssennagger N, Kies AK, van Mil SWC. Protein fermentation in the gut; implications for intestinal dysfunction in humans, pigs, and poultry. Am J Physiol Gastrointest Liver Physiol 2018;315:G159-G170.
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  7. Beaumont M, Portune KJ, Steuer N, et al. Quantity and source of dietary protein influence metabolite production by gut microbiota and rectal mucosa gene expression: a randomized, parallel, double-blind trial in overweight humans. Am J Clin Nutr 2017;106:1005-1019.
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  8. Geypens B, Claus D, Evenepoel P, et al. Influence of dietary protein supplements on the formation of bacterial metabolites in the colon. Gut 1997;41:70-76.
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