Unabsorbed Carbohydrate Research Articles

Determination of sweetener specificity of horse gut-expressed sweet taste receptor T1R2-T1R3 and its significance for energy provision and hydration.

Studies carried out in several species have demonstrated that detection of low-calorie sweeteners in the lumen of the intestine, by the sweet receptor, T1R2-T1R3, initiates a signaling pathway leading to enhanced expression and activity of intestinal Na+/glucose cotransporter 1, SGLT1. This results in an increased gut capacity to absorb glucose, sodium chloride and water, the basis for oral rehydration therapy. Horses express T1R2, T1R3 and downstream signaling elements in the intestinal tissue. As such, the potential of sweetener-stimulation of T1R2-T1R3 leading to upregulation of SGLT1 allows the provision of more glucose (energy) and hydration for horses. This is especially important when the need for glucose increases during strenuous exercise, pregnancy, and lactation. There are significant differences among species in the ability to detect sweeteners. Amino acid substitutions and pseudogenization of taste receptor genes underlie these variations. Nothing is known about the sweetener specificity of horse T1R2-T1R3. Using heterologous expression methodology, we demonstrate that sweeteners sucralose, stevia and neohesperidin dihydrochalcone (NHDC) activate horse T1R2-T1R3, but cyclamate does not. Determination of sweetener specificity of equine sweet receptor is crucial for developing suitable dietary additives to optimize glucose absorption, hydration and avoiding the intestinal disease brought about by microbial fermentation of unabsorbed carbohydrate reaching the large intestine.

Serum Acetate:Propionate Ratio Is Related to Serum Cholesterol in Men but Not Women

Acetic and propionic acids, produced by colonic fermentation of unabsorbed carbohydrates, may influence systemic lipid metabolism. To determine whether the ratio of the concentrations of acetate to propionate in peripheral serum of fasting humans was related to serum cholesterol, we studied 62 men [age 45 ± 17 y (mean ± SD), range 19–74 y; body mass index 25.0 ± 2.8 kg/m2] and 69 women [43 ± 18 y, (range, 18–77 y); body mass index 23.0 ± 3.1 kg/m2] with normal serum lipid concentrations. The concentrations of serum acetate, propionate and buty-rate (means ± SD) were similar in men (98 ± 33, 3.8 ± 1.5 and 2.3 ± 1.5 µmol/L, respectively) and women (92 ± 38, 3.9 ± 1.9 and 2.3 ± 1.6 µmol/L). There were significant positive relationships between the serum acetate:propionate ratio and total cholesterol (r = 0.466, P = 0.0002) and LDL cholesterol (r = 0.384, P = 0.0023) in men, but in women the relationships were not significant (R = 0.174, P = 0.15 and r = 0.135, P = 0.27, respectively). The relationships in men remained significant after adjustment for age and body mass index. These data support the hypothesis that, at least in men, colonic short-chain fatty acids influence systemic lipid metabolism. The relationships among the factors influencing colonic short-chain fatty acid production, the enterohepatic circulation of endogenous estrogens, dietary phytoestrogens and blood lipids in women, however, need further clarification.

Temporal Changes in Fecal Unabsorbed Carbohydrates Relative to Perturbations in Gut Microbiome of Neonatal Calves: Emerging of Diarrhea Induced by Extended-Spectrum β-lactamase-Producing Enteroaggregative Escherichia coli.

Early gut microbiota development and colonization are crucial for the long-term health and performance of ruminants. However, cognition among these microbiota is still vague, particularly among the neonatal dairy calves. Here, extended-spectrum β-lactamase-producing enteroaggregative E. coli (ESBL-EAEC)-induced temporal changes in diversity, stability, and composition of gut microbiota were investigated among the neonatal female calves, with the view of discerning potential biomarkers of this arising diarrhea cases in local pastures. Nearly, 116 newborn calves were enrolled in this time period study during their first 2 weeks of life, and a total of 40 selected fecal samples from corresponding calves were used in this study. The results revealed that differentiated gut microbiome and metabolome discerned from neonatal calves were accompanied by bacterial infections over time. Commensal organisms like Butyricicoccus, Faecalibacterium, Ruminococcus, Collinsella, and Coriobacterium, as key microbial markers, mainly distinguish “healthy” and “diarrheic” gut microbiome. Random forest machine learning algorithm indicated that enriched fecal carbohydrates, including rhamnose and N-acetyl-D-glucosamine, and abundant short-chain fatty acids (SCFAs) existed in healthy ones. In addition, Spearman correlation results suggested that the presence of Butyricicoccus, Faecalibacterium, Collinsella, and Coriobacterium, key commensal bacteria of healthy calves, is positively related to high production of unabsorbed carbohydrates, SCFAs, and other prebiotics, and negatively correlated to increased concentrations of lactic acid, hippuric acid, and α-linolenic acid. Our data suggested that ESBL-EAEC-induced diarrhea in female calves could be forecasted by alterations in the gut microbiome and markedly changed unabsorbed carbohydrates in feces during early lives, which might be conducive to conduct early interventions to ameliorate clinical symptoms of diarrhea induced by the rising prevalence of ESBL-EAEC.

Rare Hypomorphic Sucrase Isomaltase Variants in Relation to Irritable Bowel Syndrome Risk in UK Biobank

Rare Hypomorphic Sucrase Isomaltase Variants in Relation to Irritable Bowel Syndrome Risk in UK Biobank

Inhibitory effect of Artocarpus lakoocha Roxb and oxyresveratrol on α-glucosidase and sugar digestion in Caco-2 cells

Long-term diabetic complications are exacerbated by post-prandial hyperglycemia which could be ameliorated by α-glucosidase inhibitor including oxyresveratrol. Puag-Haad is an aqueous extract from Artocarpus lakoocha Roxb. containing ~65% oxyresveratrol. Oxyresveratrol is an inhibitor of isolated yeast α-glucosidase enzyme but has not been tested on intact gut enterocytes where the enzyme is membrane-bound. Accordingly, differentiated Caco-2 cells that contain the native enzyme were used to test maltose hydrolysis in the present study. The results demonstrated that purified yeast α-glucosidase was non-competitively inhibited by oxyresveratrol (Ki 54.4 ± 0.7 μg/mL) and Puag-Haad (2.7 ± 0.1 μg/mL) compared to 153.8 ± 4.3 μg/mL acarbose, an anti-diabetic drug. In differentiated Caco-2 cells, both oxyresveratrol and Puag-Haad inhibited maltose hydrolysis with lesser potency compared to acarbose. Thus, although weaker than acarbose, oxyresveratrol and Puag-Haad do not inhibit pancreatic amylase which might be a therapeutic asset in preventing fermentation of unabsorbed carbohydrate causes abdominal bloating, flatulence, or diarrhea. Oxyresveratrol and Puag-Haad may help control postprandial hyperglycemia with low risk of gastrointestinal side effects.

A131 MALNUTRITION FOLLOWING IMPLEMENTATION OF A STRICT LOW FODMAP DIET FOR IBS

Abstract Background Low fermentable oligosaccharides, disaccharides, monosaccharides and polysaccharides, polyols (FODMAP) diet is an elimination diet recommended for the symptom management of irritable bowel syndrome (IBS). It involves reducing the amount of unabsorbed and fermentable carbohydrates in attempt to decrease osmotic overload and gas production. This diet may be deficient in calcium and carbohydrates and alter the gut microbiota, however, its long-term nutritional implications are unknown. Thus, the 2019 CAG Guidelines for management of IBS suggest its short-term use with dietician supervision. To our knowledge, no previous cases of malnutrition secondary to a low FODMAP diet have been reported. Aims We report of case of severe weight loss and laboratory evidence of malnutrition following a low FODMAP diet in a patient with IBS. Methods Data was obtained by chart review, patient interview and review of relevant literature. Results A 40-year-old otherwise healthy female presented to the outpatient gastroenterology clinic for assessment of IBS in fall of 2018. At that time, she had been moderately restricting FODMAPs for several months to reduce abdominal pain and bloating. After her initial clinic visit, she followed a strict low FODMAP diet for 1 month, followed by slow and gradual re-introduction of high FODMAP containing foods. This was self-implemented without the supervision of a dietician, using on-line resources. From fall of 2018 to early 2019, she lost 12 percent of her body weight secondary to dietary restriction. While there was some improvement in bloating and pain, she developed significant fatigue. Blood work prior to implementation of low FODMAPs diet was normal, including INR of 1.2, albumin of 45 g/L, neutrophil count 2.2 x 10E9/L, and alkaline phosphatase 31 U/L (30–110 U/L). In spring of 2019, 5 months after starting a low FODMAP diet, her INR was elevated at 1.4, neutrophils low at 1.6 x 10^9/L, alkaline phosphatase low at 32 U/L (35 U/L – 120 U/L), with normal albumin of 45 g/L. After consulting a hematology specialist, she was advised to resume adequate dietary intake. She slowly returned to her baseline diet, but excluded lactose, beans, fruit, eggs, nuts and oats. While she restored her body weight by Fall 2019, her gut symptoms returned, although had improved overall. Her lab work showed normal neutrophils of 2.7 x 10^9/L, INR 1.3, with unchanged albumin at 45g/L. Conclusions While these are indirect markers of nutritional adequacy, the timeline and associated weight loss are highly suggestive of dietary inadequacy secondary to FODMAP restriction. Serum albumin remained normal as FODMAP restriction does not affect dietary protein intake. This case exemplifies the danger of initiating extreme dietary restriction in self-management manner and stresses the need of dietician supervision of such a restrictive diet. Funding Agencies None

The diagnosis of small intestinal bacterial overgrowth: Two steps forward, one step backwards?

Small intestinal bacterial overgrowth (SIBO) was originally described decades ago as a cause of malabsorption among individuals with abnormal intestinal anatomy and/or impaired gastric acid secretion and intestinal motor functions. More recently, the concept of SIBO has been expanded to explain symptoms among a much broader patient population-a move that brings the definition of SIBO into much sharper focus. For largely logistical reasons, breath tests and, especially, those based on the excretion of hydrogen consequent on the fermentation of unabsorbed carbohydrate substrates, have almost entirely replaced jejunal aspirates in the diagnosis of SIBO. Ever bedeviled by concerns regarding their reliability, hydrogen breath tests have now come under even more critical scrutiny with the study from Sundin and colleagues in this issue suggesting that their sole function is to detect carbohydrate malabsorption and that they are incapable of defining SIBO.

A fast and accurate way to determine short chain fatty acids in mouse feces based on GC–MS

Short-chain fatty acids (SCFAs) in the gut are mainly produced by the anaerobic microbial fermentation of unabsorbed dietary carbohydrates in the large bowel. Quantitative determinations of SCFAs in feces and colonic contents are necessary when studying the impact of fiber-rich food (such as fruits and vegetables) on health. We made the following crucial improvements to the method currently widely used: optimized the lyophilization period from 12 h to 3.5 h; disposed of the procedure for precise weight control; lowered the extraction temperature from 25 °C to 4 °C; shortened the extraction time from 45 min to 15 min; and significantly improved the extraction efficiency of acetic acid, propionic acid and butyric acid by 12.91%, 19.95% and 13.08%, respectively. Furthermore, to evaluate the applicability of this novel approach, we applied our method to determine the SCFAs in the feces and colonic contents of mice fed on different diets, and observed distinct results.

Increase in breath hydrogen concentration was correlated with the main pancreatic duct stenosis

Background. Hydrogen is produced from unabsorbed carbohydrates in the intestine through degradation and metabolism by hydrogenase of intestinal bacteria. The hydrogen is then partially diffused into blood flow and released and detected in exhaled breath. Pancreatic juice production is decreased in patients with reduced pancreatic exocrine function, including those with pancreatic cancer, thus decreasing digestion and absorption of nutrients including carbohydrates, which may increase undigested carbohydrates in the intestine and increase breath hydrogen concentration (BHC). The aim of this study was to investigate the association between BHC and pancreatic diseases. Methods. A retrospective study was designed and 68 patients underwent morning fasting breath hydrogen test. Since there is no clear standard, normal BHC, the median of the measured values from the subjects (9 ppm) was adopted as the standard. The subjects were classified into those with a value exceeding the median (BHC high group: 32 patients) and a value equal to or below the median (BHC low group: 36 patients). Patients characteristics, blood test results and imaging findings characteristic of pancreatic diseases were compared between the groups. Results. The age was significantly higher (P = 0.010) and the incidences of pancreatic ductal adenocarcinoma and autoimmune pancreatitis were significantly higher (P = 0.018 and P = 0.004, respectively) in the BHC high group. With respect to the blood test items, the Alb level was significantly lower in the BHC high group (P = 0.005). With respect to the characteristic imaging findings of pancreatic diseases, the proportions of patients with pancreatic enlargement, the main pancreatic duct (MPD) stenosis, and the MPD dilatation were significantly higher in the BHC high group (P = 0.022, P < 0.001, and P = 0.002, respectively). On univariate analysis, only the MPD stenosis was extracted as an independent factor (P = 0.014). Conclusion. It was suggested that the fasting BHC is associated with pancreatic diseases causing stenosis of the MPD, including pancreatic cancer (UMIN000020777).

D-lactic acidosis: an underrecognized complication of short bowel syndrome.

D-lactic acidosis or D-lactate encephalopathy is a rare condition that occurs primarily in individuals who have a history of short bowel syndrome. The unabsorbed carbohydrates act as a substrate for colonic bacteria to form D-lactic acid among other organic acids. The acidic pH generated as a result of D-lactate production further propagates production of D-lactic acid, hence giving rise to a vicious cycle. D-lactic acid accumulation in the blood can cause neurologic symptoms such as delirium, ataxia, and slurred speech. Diagnosis is made by a combination of clinical and laboratory data including special assays for D-lactate. Treatment includes correcting the acidosis and decreasing substrate for D-lactate such as carbohydrates in meals. In addition, antibiotics can be used to clear colonic flora. Although newer techniques for diagnosis and treatment are being developed, clinical diagnosis still holds paramount importance, as there can be many confounders in the diagnosis as will be discussed subsequently.

Abnormal accumulation of intestinal fluid following ingestion of an unabsorbable carbohydrate in patients with irritable bowel syndrome: an MRI study.

Postprandial discomfort following intake of poorly absorbable, but fermentable carbohydrates is a common complaint in patients with irritable bowel syndrome (IBS). We used lactulose as a model substance for this group of symptom triggering carbohydrates, aiming to visualize the intestinal response in IBS patients compared to healthy controls. Patients with IBS according to Rome III criteria (n = 52) and healthy controls (n = 16) underwent a lactulose challenge test. By using magnetic resonance imaging, we measured small bowel water content (SBWC), and distension (diameter) of the distal ileum and the colon, both in fasting state and 1 h after ingestion of 10 g lactulose. We recorded symptoms after lactulose ingestion. Lactulose provoked significantly more symptoms in IBS patients than in healthy controls (p < 0.0001). SBWC increased more in the patient group compared to the control group (p = 0.0005). The postprandial diameter of the terminal ileum was larger in patients with IBS and the postprandial diameter of the ascending colon was smaller in patients with diarrhea-predominant phenotype (IBS-D). Symptoms were not correlated with change in SBWC (r = 0.05; p = 0.11), nor to the diameters of the terminal ileum or the colon. Compared to healthy controls, IBS patients developed more symptoms and had an abnormal accumulation of fluid in the small bowel in response to ingestion of the unabsorbable carbohydrate lactulose. This may be due to impaired motor activity of the small intestine or impaired function of the ileocecal segment.

Fructose Malabsorption in Patients With Irritable Bowel Syndrome-like Symptoms: What Is the Role in the Pathogenesis and Clinical Implication?

Article: Unclear abdominal discomfort: pivotal role of carbohydrate malabsorption Goebel-Stengel M, Stengel A, Schmidtmann M, van der Voort I, Kobelt P, Mönnikes H.

What does indirect calorimetry really tell us?

What does indirect calorimetry really tell us?

Breath tests and irritable bowel syndrome.

Breath tests are non-invasive tests and can detect H₂ and CH₄ gases which are produced by bacterial fermentation of unabsorbed intestinal carbohydrate and are excreted in the breath. These tests are used in the diagnosis of carbohydrate malabsorption, small intestinal bacterial overgrowth, and for measuring the orocecal transit time. Malabsorption of carbohydrates is a key trigger of irritable bowel syndrome (IBS)-type symptoms such as diarrhea and/or constipation, bloating, excess flatulence, headaches and lack of energy. Abdominal bloating is a common nonspecific symptom which can negatively impact quality of life. It may reflect dietary imbalance, such as excess fiber intake, or may be a manifestation of IBS. However, bloating may also represent small intestinal bacterial overgrowth. Patients with persistent symptoms of abdominal bloating and distension despite dietary interventions should be referred for H₂ breath testing to determine the presence or absence of bacterial overgrowth. If bacterial overgrowth is identified, patients are typically treated with antibiotics. Evaluation of IBS generally includes testing of other disorders that cause similar symptoms. Carbohydrate malabsorption (lactose, fructose, sorbitol) can cause abdominal fullness, bloating, nausea, abdominal pain, flatulence, and diarrhea, which are similar to the symptoms of IBS. However, it is unclear if these digestive disorders contribute to or cause the symptoms of IBS. Research studies show that a proper diagnosis and effective dietary intervention significantly reduces the severity and frequency of gastrointestinal symptoms in IBS. Thus, diagnosis of malabsorption of these carbohydrates in IBS using a breath test is very important to guide the clinician in the proper treatment of IBS patients.

Pathobiology and Potential Therapeutic Value of Intestinal Short-Chain Fatty Acids in Gut Inflammation and Obesity

The lumen of the gastrointestinal tract contains many substances produced from the breakdown of foodstuffs, from salivary, esophageal, intestinal, hepatic, and pancreatic secretions, and from sloughed cells present in the gastrointestinal lumen. Although these substances were traditionally regarded as waste products, there is increasing realization that many can be biologically active, either as signalling compounds or as nutrients. For example, proteins are broken down into amino acids, which are then sensed by nutrient receptors. The gut microbiome, which is at highest abundance in the ileocecum, has powerful metabolic activity, digesting and breaking down unabsorbed carbohydrates, proteins, and other ingested nutrients into phenols, amines, volatile organic compounds, methane, carbon dioxide, hydrogen, and hydrogen sulfide into volatile fatty acids, also called short-chain fatty acids (SCFAs). These latter substances are the topic of this review. In this review, we will briefly discuss recent advances in the understanding SCFA production, signalling, and absorption, followed by a detailed description and discussion of trials of SCFAs, probiotics, and prebiotics in the treatment of gastrointestinal disease, in particular ulcerative colitis (UC), pouchitis, short bowel syndrome, and obesity.

Effects of a late supper on digestion and the absorption of dietary carbohydrates in the following morning

BackgroundOur previous experiment showed that the light intensity exposed on the subjects during evening time had no effect in the following morning on the efficiency of the digestion and absorption of dietary carbohydrates ingested at a usual suppertime. People who keep late hours usually have a late suppertime; thus, we examined the effects of a late suppertime on gastrointestinal activity in the following morning in comparison to that of a usual suppertime.MethodsTwelve female university students volunteered as paid participants. The breath hydrogen test was carried out to estimate the amount of unabsorbed dietary carbohydrates and the percentage of the total amount of dietary carbohydrates in the breakfast that were unabsorbed, as well as to estimate oro-cecal transit time. The respiratory quotient was also measured to find the ratio of carbohydrates/lipid metabolism in the post-breakfast state. Subjects’ peripheral blood glucose concentration was measured by a blood glucose meter. The subjects participated under two different experimental conditions: with a usual suppertime (having supper at 18:00) and a late suppertime (having supper at 23:00).ResultsThe efficiency of the digestion and absorption of dietary carbohydrates in the breakfast under late suppertime conditions was higher than that under usual suppertime conditions. Usual or late suppertime had no effect on the ratio of carbohydrates to lipids oxidized after the subjects had breakfast. There were significant differences in the blood glucose level between the two conditions at 30, 60, 120, 150, and 180 minutes after having breakfast, whereas the mean blood glucose level under late suppertime conditions was significantly higher than under usual suppertime conditions.ConclusionsHaving a late supper showed a worse effect on postprandial serum glucose profiles the following morning. This study confirmed that keeping our usual meal timing is important for our health.

A case of pneumatosis cystoides intestinalis mimicking familial adenomatous polyposis

In rare cases the diagnosis of Familial Adenomatous Polyposis (FAP) may not be simple or straightforward. We describe the case of a 54-year man in whom endoscopic and histological features of FAP led to proctocolectomy with ileoanal anastomosis. At anatomical examination, air-filled cystic formations in the submucosa and subserosa of the entire large bowel led to the diagnosis of "Pneumatosis Cystoides Intestinalis", a rare clinical condition featured by the infiltration (or the production) of gas within the intestinal wall. In this case the disease was associated with a long-lasting ingestion of acarbose; as suggested by previous reports, it is possible that gas produced by the fermentation of this unabsorbable carbohydrate penetrates the bowel wall giving origin to cystic formation and to the endoscopic appearance of several polypoid lesions in the large bowel. This report indicates that in rare occasions Pneumatosis Intestinalis can lead to a wrong diagnosis of FAP.

Congenital Sucrase‐Isomaltase Deficiency

Congenital Sucrase‐Isomaltase Deficiency

Comparison of seasonal variation in the fasting respiratory quotient of young Japanese, Polish and Thai women in relation to seasonal change in their percent body fat

BackgroundFrom the viewpoint of human physiological adaptability, we previously investigated seasonal variation in the amount of unabsorbed dietary carbohydrates from the intestine after breakfast in Japanese, Polish and Thai participants. In this investigation we found that there were significant seasonal variations in the amount of unabsorbed dietary carbohydrates in Japanese and Polish participants, while we could not find significant seasonal variation in Thai participants. These facts prompted us to examine seasonal variations in the respiratory quotient after an overnight fast (an indicator of the ratio of carbohydrate and fat oxidized after the last meal) with female university students living in Osaka (Japan), Poznan (Poland) and Chiang Mai (Thailand).MethodsWe enrolled 30, 33 and 32 paid participants in Japan, Poland and Thailand, respectively, and measurements were taken over the course of one full year. Fasting respiratory quotient was measured with the participants in their postabsorptive state (after 12 hours or more fasting before respiratory quotient measurement). Respiratory quotient measurements were carried out by means of indirect calorimetry using the mixing chamber method. The percent body fat was measured using an electric bioelectrical impedance analysis scale. Food intake of the participants in Osaka and Poznan were carried out by the Food Frequency Questionnaire method.ResultsThere were different seasonal variations in the fasting respiratory quotient values in the three different populations; with a significant seasonal variation in the fasting respiratory quotient values in Japanese participants, while those in Polish and Thai participants were non-significant. We found that there were significant seasonal changes in the percent body fat in the three populations but we could not find any significant correlation between the fasting respiratory quotient values and the percent body fat.ConclusionsThere were different seasonal variations in the fasting respiratory quotient values in the three different populations. There were significant seasonal changes in the percent body fat in the three populations but no significant correlation between the fasting respiratory quotient values and the percent body fat.

The Hydrogen Breath Test: New Uses for an Old Test

The Hydrogen Breath Test: New Uses for an Old Test