Psyllium reduces inulin-induced colonic gas production in IBS: MRI and in vitro fermentation studies

ObjectiveHealth-promoting dietary fibre including inulin often triggers gastrointestinal symptoms in patients with IBS, limiting their intake. Our aim was to test if coadministering psyllium with inulin would reduce gas production.DesignA randomised, four-period, four-treatment, placebo-controlled, crossover trial in 19 patients with IBS. Subjects ingested a 500 mL test drink containing either inulin 20 g, psyllium 20 g, inulin 20 g+ psyllium 20 g or dextrose 20 g (placebo). Breath hydrogen was measured every 30 min with MRI scans hourly for 6 hours. Faecal samples from a subset of the patients with IBS were tested using an in vitro fermentation model. Primary endpoint was colonic gas assessed by MRI.ResultsColonic gas rose steadily from 0 to 6 hours, with inulin causing the greatest rise, median (IQR) AUC(0–360 min) 3145 (848–6502) mL·min. This was significantly reduced with inulin and psyllium coadministration to 618 (62–2345) mL·min (p=0.02), not significantly different from placebo. Colonic volumes AUC(0–360 min) were significantly larger than placebo for both inulin (p=0.002) and inulin and psyllium coadministration (p=0.005). Breath hydrogen rose significantly from 120 min after inulin but not psyllium; coadministration of psyllium with inulin delayed and reduced the maximum increase, AUC(0–360 min) from 7230 (3255–17910) ppm·hour to 1035 (360–4320) ppm·hour, p=0.007.Fermentation in vitro produced more gas with inulin than psyllium. Combining psyllium with inulin did not reduce gas production.ConclusionsPsyllium reduced inulin-related gas production in patients with IBS but does not directly inhibit fermentation. Whether coadministration with psyllium increases the tolerability of prebiotics in IBS warrants further study.Trial registration numberNCT03265002.

Measurement of fasting breath hydrogen concentration as a simple diagnostic method for pancreatic exocrine insufficiency

Background Pancreatic exocrine insufficiency (PEI) is associated with the outcome of pancreatic disease. However, there is no method for assessing PEI that can be used noninvasively and easily for outpatient. It has been reported that changes in intestinal bacteria caused by PEI may increase breath hydrogen concentration (BHC) levels during glucose or lactose loading. We have evaluated the usefulness of fasting breath hydrogen concentration (FBHC) measurement without glucose loading for the evaluation of PEI. Methods Sixty patients underwent FBHC measurement, BT-PABA testing, and microbiome analysis. They were classified into PEI group (PABA excretion rate < 73.4%, n = 30) and non-PEI group (n = 30). The FBHC of the two groups were compared, and the diagnostic ability of PEI by them was evaluated. The 16 s rRNA (V3–V4) from fecal samples was analyzed by MiSeq. Results FBHC levels was higher in the PEI group 15.70 (1.4 to 77.0) ppm than in the non-PEI group 2.80 (0.7 to 28.2) ppm (P < 0.0001). FBHC was negatively correlated with PABA excretion rate (r = − 0.523, P < 0.001). The cutoff value of FBHC of 10.7 ppm (95% CI: 0.678–0.913, P < 0.001) showed a sensitivity of 73.3% and specificity of 83.3% for PEI diagnosis. In the PEI group, there was a significant increase of relative abundance of phylum Firmicutes (P < 0.05) and the genus Clostridium (P < 0.05). Conclusion FBHC shows good potential as a simple and repeatable test for the diagnosis of PEI. The elevated FBHC levels may be caused by hydrogen-producing bacteria such as Clostridium.

Evaluation of the Relative Available Energy of Cyclic Nigerosylnigerose (CNN) using breath hydrogen excretion in healthy humans

Cyclic nigerosylnigerose (CNN) is a cyclic tetrasaccharide with properties distinct from those of other conventional cyclodextrins. We investigated the relative available energy of CNN in healthy humans. CNN digestibility was determined using brush border membrane vesicles from the small intestines of rats. CNN was not hydrolyzed by rat intestinal enzymes. To investigate breath hydrogen excretion, thirteen human subjects were included in a double-blind cross-over, randomized, placebo-controlled study. The effects of CNN on hydrogen excretion were compared with those of a typical nondigestible, fermentable fructooligosaccharide (FOS). In the study participants, hydrogen excretion hardly increased upon CNN and was remarkably lower than for FOS. The available energy value was determined using the fermentability based on breath hydrogen excretion and was evaluated as 0 kcal/g for CNN. CNN was hardly metabolized and hence may be used as a low-energy dietary fiber.

Measurement of Fasting Breath Hydrogen Concentration as a Simple Diagnostic Method for Pancreatic Exocrine Insufficiency

BackgroundPancreatic exocrine insufficiency (PEI) is associated with the outcome of pancreatic disease. However, there is no method for assessing PEI that can be used noninvasively and easily for outpatient. It has been reported that changes in intestinal bacteria caused by PEI may increase breath hydrogen concentration (BHC) levels during glucose or lactose loading. We have evaluated the usefulness of fasting breath hydrogen concentration (FBHC) measurement without glucose loading for the evaluation of PEI.MethodsSixty patients underwent FBHC measurement, BT-PABA testing, and microbiome analysis.They were classified into PEI group (PABA excretion rate <73.4%, n=30) and non-PEI group (n=30). The FBHC of the two groups were compared, and the diagnostic ability of PEI by them was evaluated. The 16s rRNA (V3-V4) from fecal samples was analyzed by MiSeq.ResultsFBHC levels was higher in the PEI group (15.70 (1.4 to 77.0) than in the non-PEI group 2.80 (0.7 to 28.2) ppm, P 0.0001). FBHC was negatively correlated with PABA excretion rate (r = -0.523, P < 0.001). The cutoff value of FBHC of 10.7 ppm (95% CI: 0.678-0.913, P 0.001) showed a sensitivity of 73.3% and specificity of 83.3% for PEI diagnosis. In the PEI group, there was a significant increase of relative abundance of phylum Firmicutes (P < 0.05) and the genus Clostridium (P < 0.05). ConclusionFBHC shows good potential as a simple and repeatable test for the diagnosis of PEI. The elevated FBHC levels may be caused by hydrogen-producing bacteria such as Clostridium.

The Gut Microbiome and Abiotic Factors as Potential Determinants of Postprandial Glucose Responses: A Single-Arm Meal Study

The gut microbiome has combined with other person-specific information, such as blood parameters, dietary habits, anthropometrics, and physical activity been found to predict personalized postprandial glucose responses (PPGRs) to various foods. Yet, the contributions of specific microbiome taxa, measures of fermentation, and abiotic factors in the colon to glycemic control remain elusive. We tested whether PPGRs 60 min after a standardized breakfast was associated with gut microbial α-diversity (primary outcome) and explored whether postprandial responses of glucose and insulin were associated with specific microbiome taxa, colonic fermentation as reflected by fecal short-chain fatty acids (SCFAs), and breath hydrogen and methane exhalation, as well as abiotic factors including fecal pH, fecal water content, fecal energy density, intestinal transit time (ITT), and stool consistency. A single-arm meal trial was conducted. A total of 31 healthy (24 female and seven male) subjects consumed a standardized evening meal and a subsequent standardized breakfast (1,499 kJ) where blood was collected for analysis of postprandial glucose and insulin responses. PPGRs to the same breakfast varied across the healthy subjects. The largest inter-individual variability in PPGRs was observed 60 min after the meal but was not associated with gut microbial α-diversity. In addition, no significant associations were observed between postprandial responses and specific taxa of the gut microbiome, measures of colonic fermentation, ITT, or other abiotic factors. However, fasting glucose concentrations were negatively associated with ITT, and fasting insulin was positively associated with fasting breath hydrogen. In conclusion, the gut microbiome, measures of colonic fermentation, and abiotic factors were not shown to be significantly associated with variability in postprandial responses, suggesting that contributions of the gut microbiome, colonic fermentation, and abiotic factors to PPGRs may be subtle in healthy adults.

The Effect of Soluble Fiber Dextrin on Subjective and Physiological Markers of Appetite: A Randomized Trial

Obesity is a leading public health problem throughout the world. The development of foods that increase satiety and reduce food may aid weight management. This study determined the effect of consuming soluble fiber dextrin (SFD) on appetite, appetitive hormones, breath hydrogen and food intake in adults. Forty-three participants completed this study. For each treatment, 50% of the SFD was provided in liquid form as part of breakfast and 50% in solid form as a morning snack. Appetite questionnaires, blood and breath samples were collected immediately before breakfast and at regular intervals during the test session. The participants consumed an ad libitum lunch meal, afternoon snack and dinner meal, and the amount eaten was recorded. Following dinner, participants left the laboratory but were required to keep a diet diary for the remainder of the day. Breath hydrogen concentration was significantly higher following the consumption of SFD compared to control (p < 0.05). There was no observed overall treatment effect of consuming SFD on GLP-1 (Glucagon-Like-Peptide-1), ghrelin, CCK-8 (Cholecystokinin) or PYY3-36 (Petptide YY) (p > 0.05). Moreover, consuming foods containing SFD had no effect on subjective appetite or food intake (p > 0.05). Consuming foods containing SFD increased breath hydrogen but did not influence food intake, appetite or appetitive hormones. However, the limitations of this study may have individually or collectively masked an effect of SFD on food intake and appetite.

Trial of Available Energy Evaluation of Highly Cross-linked Starch and Modified Cellulose Based on Breath H2 Excretion

Background: The energy value of a substance is essential in nutritional labeling. However, the available energy of newly developed highly cross-linked phosphate starch (HCPS-N) and modified cellulose (MC) are unknown. Objective: To evaluate the available energy of HCPS-N and MC, an indirect and simple method which was applied as an indicator of the fermentability based on the breath hydrogen excretion, was used. Methods: HCPS-N was made from tapioca starch by polymerization in the presence of 0.5% phosphoric acid. MC was made from microcrystalline cellulose, maltodextrin, and karaya gum to attain a highly stable suspension. The present study was carried out using a within-subject, repeatedmeasures design. Blood was collected at 30 min intervals for 3 h after the ingestion of 30 g of a test substance. The end-respiratory gas was collected for 14 h after ingestion of 5 g of a test substance to evaluate the available energy. Results and Discussion: Plasma glucose and insulin levels did not elevate after the ingestion of HCPS-N, although they increased significantly after glucose ingestion. In the experiments to evaluate the available energy, breath hydrogen excretion after ingesting HCPS-N did not increase distinctly during the experiment. Breath hydrogen excretion after preceding HCPS-P (0 kcal) ingestion was also markedly smaller compared with the peak value at 4 h after FOS ingestion. For the ingestion of MC, breath hydrogen excretion increased scarcely, and the basal level remained until the end of the experiment. Conclusion: The available energies were evaluated to be 0 kcal/g for HCPS-N and 1 kcal/g for MC in healthy humans.