Dietary Fiber and Coronary Heart Disease
Robert E.C. Wildman, Richard S. Bruno in Handbook of Nutraceuticals and Functional Foods, 2019
Different fiber molecules are subject to varying levels of bacterial degradation in the colon (Table 10.3). For instance, pectin, mucilages, and gums seem to be almost completely fermented. Meanwhile, cellulose and hemicellulose are only partly degraded and the non-carbohydrate nature of lignin allows it to go virtually unfermented. Similarly, some RSs escape colonic fermentation and are excreted in the feces. The degree of fermentation is dependent on the category and source of RS consumed. The physical structure of the plant itself may be associated with the degree of degradation of food fibers by intestinal bacteria. As an example, fibers derived from fruits and vegetables appear to be, in general, more fermentable than those from cereal grains. VFAs, namely acetic acid (2:0), proprionic acid (3:0), and butyric acid (4:0), are among the products of bacterial fermentation. As mentioned above, these fatty acids can be oxidized for ATP production in mucosal cells of the colon wall. Furthermore, these fatty acids are fairly water soluble and can be absorbed into the portal circulation. Other products of bacterial fermentation of dietary fibers include hydrogen gas (H2), carbon dioxide (CO2), and methane (CH4). These products may lead to occasional uncomfortable gas buildup in the colon that may occur with high fiber consumption. The presence of H2 in the breath (hydrogen breath test) is often used clinically as an estimation of bacterial fermentation. Once produced, H2 dissolves into the blood and circulates to the lungs.
Postulated Physiological and Pathophysiological Roles on Motility
Edwin E. Daniel in Neuropeptide Function in the Gastrointestinal Tract, 2019
In contrast to these findings on electrical activity of small bowel in the dog, no significant effect of CR-1505 (loxiglumide) was found on small bowel transit in healthy volunteers.179 The results in humans suggest that endogenous CCK does not play a major role in small bowel function in man. However, the test used (hydrogen breath test) might be too insensitive to detect changes in the motility pattern. Furthermore, the importance of CCK could be rather variable in response to the composition of the applied meal, as suggested by release studies. Further studies with specific CCK-antagonists using different test meals, especially with high fat content and more elaborate techniques for monitoring gut function, are needed in humans and in laboratory animals to establish the precise role of endogenous CCK in the postprandial state.
Do I Have IBS?
Melissa G. Hunt, Aaron T. Beck in Reclaim Your Life From IBS, 2022
Another diagnostic test for lactose intolerance is the hydrogen breath test. Undigested lactose is broken down by bacteria in the gut, leading to the production of hydrogen and methane gases, which can be detected in the breath. Unfortunately, the results of those tests are sometimes borderline or equivocal, and there are often long wait times to have the test done. Sometimes the test is combined with a lactose tolerance test, in which you undergo a blood test to measure the amount of glucose in your blood. If you’re digesting lactose, your glucose levels should rise after consuming a lot of it. If your blood sugar doesn’t rise, it suggests that you’re not breaking the lactose down. Eventually, a simple genetic test may be used to identify individuals who are lactose-intolerant, but that is not available in routine clinical practice yet. Because the hydrogen breath test, like the celiac blood test, is not particularly invasive, it may be worth doing to rule out the possibility that your symptoms are being caused by lactose intolerance.
Lactose after Roux-en-Y gastric bypass for morbid obesity, is it a problem?
Published in Scandinavian Journal of Gastroenterology, 2020
F. Westerink, H. Beijderwellen, I. L. Huibregtse, M. L. A. De Hoog, L. M. De Brauw, D. P. M. Brandjes, V. E. A Gerdes
The lactose hydrogen breath test (LBT) and lactose tolerance test (LTT) are the two most frequently used tests in clinical practise and were therefore used in this study. Over 25% of postoperative patients tested positive on the LBT, twice as many as preoperative patients and with an even larger difference in the Non-Northwest European subgroup. In the normal population, the LBT has a sensitivity and specificity of 88 and 85 percent respectively [14], but whether this is altered after RYGB is unknown. Furthermore, a positive lactose LBT may not only be the result of lactase deficiency, leading to lactose fermentation into hydrogen and methane by colonic bacteria. Gut microbiome changes are seen after RYGB and (subclinical) small intestinal bacterial overgrowth (SIBO) after RYGB is reported [18]. SIBO can influence lactose breath testing [19]. We did not exclude SIBO before lactose testing in this study, which may have led to more positive results on the lactose breath test. If so, this probably further decreases the number of patients with true lactose intolerance/malabsorption because of lactase deficiency. The relatively high methane levels we found in postoperative patients might be due to microbiome changes after RYGB.
Methane positive small intestinal bacterial overgrowth in inflammatory bowel disease and irritable bowel syndrome: A systematic review and meta-analysis
Published in Gut Microbes, 2021
Arjun Gandhi, Ayesha Shah, Michael P. Jones, Natasha Koloski, Nicholas J. Talley, Mark Morrison, Gerald Holtmann
A comprehensive literature search was performed using MEDLINE(PubMed) and Embase electronic databases from initiation (1966) up to March 2021 for all studies assessing the prevalence of SIBO in patients with IBD, IBS, and/or functional gastrointestinal disorders (FGIDs). The initial search was not limited to specific languages. A further advanced search was conducted. Grey literature was searched with Google and Google Scholar, and the ‘Snowball” method was also utilized which included pursuing through reference lists of articles as well as electronic citations, to identify all relevant articles. Search terms included “methane” OR “CH4” OR “breath test” OR “breath analysis” OR “methane breath test” OR “glucose breath test (GBT)” OR “glucose hydrogen breath test” OR “GBT” OR “lactulose breath test (LBT)” OR “lactulose hydrogen breath test (LHBT)” OR “LBT’ OR “LHBT” AND “constipation” OR “transit” OR “motility” OR “irritable bowel syndrome” OR “IBS” OR “irritable colon” OR “colonic inertia” OR “SIBO” OR “SBBO” OR “small bowel bacterial overgrowth (SBBO)” OR “small intestinal bacterial overgrowth” AND “Inflammatory bowel disease” OR “IBD”. Expert assistance was sought from the hospital librarian who helped conduct a detailed literature search strategy which is outlined in in the PRISMA flow diagram.
Intragastric fructose administration interacts with emotional state in homeostatic and hedonic brain regions
Published in Nutritional Neuroscience, 2022
Julie Iven, Jessica R. Biesiekierski, Dongxing Zhao, Jan Tack, Lukas Van Oudenhove
First, the 25 g of fructose used in our study might have been too low to observe significant effects at the self-report level as daily intake of fructose varies between 11 and 54 g. However, dosage was chosen to minimize fructose malabsorption, as 25 g is completely absorbed in 50% of the population [36]. Second, we did not perform a hydrogen breath test to exclude fructose malabsorption, however no side effects were reported by any of the participants. Third, our emotion induction paradigm could be considered unsuccessful at the behavioral level, despite the fact that this paradigm has been successfully used in previous studies [9,17]. Fourth, for this study, healthy, young, lean and healthy volunteers were included. Additional studies in patients suffering from mood disorders or emotional eating should be performed to further increase the understanding of the interaction of food and mood in this population. Fifth, we cannot exclude the effects of different molar load or osmolarities of the fructose compared to the milli-Q water used as the placebo, that could have affected hormone secretion and GI motility differentially. Last, although intragastric administration may limit the clinical relevance compared to oral intake, its mechanistic relevance may be higher as it allows for the effect of purely interoceptive gut-brain signals on hedonic outcomes, bypassing all sensory and cognitive effects.
Related Knowledge Centers
- Fructose
- Malabsorption
- Methane
- Small Intestinal Bacterial Overgrowth
- Sorbitol
- Carbohydrate
- Lactose
- NON-Invasive Procedure
- Fasting
- Breath Test