Medically reviewed by Onikepe Adegbola, MD, PhD
A recent clinical study from Thailand evaluated the effect of high and low contents of fermentable sugars in the diet on gastrointestinal symptoms like regurgitation, bloating, and irritable bowel syndrome. This study titled “The Effect of Fermentable, Oligosaccharides, Disaccharides, Monosaccharides, and Polyols (FODMAP) Meals on Transient Lower Esophageal Relaxations (TLESR) in Gastroesophageal Reflux Disease (GERD) Patients with Overlapping Irritable Bowel Syndrome (IBS)” was published in Nutrients by MDPI.
What are FODMAPS, and what happens if we eat them?
The acronym FODMAP stands for fermentable oligo-, di-, mono-, and polyols. These short-chain carbohydrates are difficult to digest. Rather than being absorbed into the circulation, they reach the large intestine and colon. These carbs are then used as fuel by gut bacteria, resulting in the generation of hydrogen (H2) and methane (CH4) gas, which can cause stomach issues in sensitive persons. By pulling fluids into the colon, FODMAPs can also cause diarrhea.
A study released in 2021 regarding a low FODMAP diet experiment found that it improved gastrointestinal symptoms in patients with gastroesophageal reflux illness (GERD). In individuals with overlapping GERD-IBS, this study investigates how low and high FODMAP meals affect transient lower esophageal sphincter relaxation (TLESR), intestinal gas production, post-meal gastroesophageal reflux, typical GERD, and other gastrointestinal symptoms.
Patients with IBS have long been linked to a wheat-based diet as producing discomfort. It has high FODMAP content. Rice meal, on the other hand, is low in FODMAPs and therefore safer for IBS patients to consume. Rice noodles are categorized as a low FODMAP food, while wheat noodles are classified as a high FODMAP item, according to the Monash University FODMAP diet application.
This randomized trial includes data from 8 patients who had GERD and non-constipation type IBS symptoms. All of the individuals had similar symptoms before the trial began. At breakfast and lunch, they were given a regular meal of 250 g rice noodles or 250 g wheat noodles. During fasting and after breakfast, all individuals exhaled breath H2 and methane CH4 gas were collected every 15 minutes for 8 hours. TLESR occurrences were also observed for 2 hours after the meal. GERD, bloating, satiety, abdominal pain, bowel urgency, nausea/vomiting, belching, chest pain/discomfort, and farts were assessed every 15 minutes for 2 hours after the meal.
Results of the study correlated with the long-existing notion that having rice meals instead of wheat meals can produce lesser regurgitation and other GI symptoms. The authors discovered that wheat noodles were linked to considerably more TLESR occurrences than rice noodles, which means a higher chance of reflux or regurgitation as the sphincter between the food pipe and the stomach is relaxing, and food content can reach the food pipe from the stomach. After each meal, patients who took wheat noodles had greater exhaled hydrogen and Methane concentrations, as well as post-meal reflux, bloating, satiety, and belching symptoms than rice noodles.
How do wheat or other high FODMAP diets affect patients with IBS?
Wheat-based foods have been reported to be the most problematic for IBS patients’ symptoms. Wheat noodles were associated with a high FODMAP, whereas rice noodles were associated with a low FODMAP. After breakfast, the change in the frequency of gastrointestinal symptoms was not considerable, but it began shortly after lunchtime. This research implies that rice noodles are entirely absorbed in the small intestine, whereas wheat noodles or high FODMAP meals are only partially digested, and some undigested sugars like lactulose are transported from the ileum to the large intestine and colon. Fermentation of lactulose in the colon, along with short-chain fatty acid (SCFA), triggers TLESRs, which is not the case with rice or low FODMAP meals.
What is the main takeaway from this study?
Wheat noodles, a high FODMAP meal, were observed to elicit higher TLESRs and classic GERD symptoms (bloating, satiety, and belching) after lunch than rice noodles, a low FODMAP meal, according to this study. The effect of high FODMAP diets on TLESRs is connected to increased intestinal gas production, suggesting a role for colonic fermentation or colonic SCFA in TLESR modulation.
Plaidum, S., Patcharatrakul, T., Promjampa, W., & Gonlachanvit, S. (2022). The effect of fermentable, oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) meals on transient lower esophageal relaxations (TLESR) in gastroesophageal reflux disease (GERD) patients with overlapping irritable bowel syndrome (IBS). Nutrients, 14(9), 1755. https://doi.org/10.3390/nu14091755