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Discussion Starter · #1 ·
This is a summary of an editorial by Fernando Azpiroz, MD, PhD *and Juan R. Malagelada, MD, PhD in the Gastroenterology ClinicsBloating -To some it is a subjective sensation of fullness or pressure inside the abdomen. To others, bloating means abdominal distensionSensation of Bloating: It could be 1)a hypersensitive abdominal wall that produces a sensation of increased abdominal tension 2)or the sensation may originate from hypersensitive abdominal viscera.e.g a) small bowel hypersensitivity that selectively affects mechanosensitive afferents, without disturbing normal perception of electrical stimulation b)there is increased perception of gastric distension in IBS'ersc)fundic distension also leads to the sensation of bloatingVisceral hypersensitivity is modulated by several mechanisms operating between the gut and the brain and this altered brain-gut communication may cause the sensation of bloatingThe tolerance of mechanical stimuli in the gut depends on muscular activity and compliance, on the number of receptors activated modified by the interaction of different stimuli in the gut . For instance, intraluminal gas is tolerated better within the colon than within the poorly compliant small bowel. Intestinal lipids, frequently related by patients to postprandial bloating, increase the sensitivity of the intestine to mechanical stimuli, Some data indicate that patients with IBS have increased sympathetic activity. Visceral perception also is known to be mediated at a cortical level and therefore may be influenced by cognitive mechanisms. MECHANISMS OF PHYSICAL ABDOMINAL EXPANSIONThe potential elements include adipose tissue (solid), fluid (endoluminal, intravascular, intraperitoneal), and endoluminal gas. Hwever fat accumulation, ascitis do not lead to bloating mostly.Abdominal bloating and distension may arise when tissular water content increases, as may occur with vascular ingurgitation and visceral edema. Also endoluminal fluid accumulation could lead to bloating. E.g 1)Accumulation of liquid in acute diarrheal conditions and in some cases of postprandial bloating2)An association between symptoms and arrival chyme( a mix ofsolid and liquid) has been shown to exist.3)The effect of fiber on bloating may be related to the luminal overload. 4)Accumulation of fecal content also may contribute to bloating, particularly in patients with constipation. The effect of gas on bloating is complicated as there are many factors that must be consider like 1)bloating and flatulence cannot be used interchangeably with each other. The ingestion of lactulose leads to flatulence but not always bloating. fiber has been shown not to affect flatulence but does affect blaoting. 2) The amout of gas produced depends on the amount of fermentable foodstuffs that remain unabsorbed in the small bowel and enter the colon, and the individual characteristics of the colonic flora. Exampleas are malabsorption disorders or SIBO. But Whether some degree of nutrient malabsorption plays a role in IBS has been disputed and exclusion diets are inconclusive In one study, even though Pimentel showed abnormal small intestinal flora by abnormal hudrogen breath tests in IBS'ers and normalization with neomycin there were no differences in another study in breath hydrogen concentration measured over 1 week were detected between healthy controls and IBS patients, although patients complained of significant bloatin.King et al concluded that ther were abnormal colonic flora because total hydrogen excretion increased in patients with IBS. This is further complicated by the fact that healthy subjects are able to propel and evacuate very large gas loads without perception of abdominal distension. 3)Propulsion and transit of intraluminal gas determine the times for diffusion into the blood and for bacterial consumption. Hence, the rate of gas transit is a critical factor that influences the volume and composition of gas in the different regions of the gut. What affects transit:1) tolerance to gas loads. In healthy people as much gas is infused in the GI tract, that much is evacuated upto 30 ml gas/min.Manometric studies detected no changes in phasic motor activity in response to slow infusion of gas in the small bowel . Gas infusion induces a tonic motor response: a contraction in the direction of the mouth to the infusion site and a relaxation distal to the collection site. Studies suggest that changes in tonic activity and capacitance of the gut due to distension may result in the displacement of large masses of luminal gas that offers low resistance to motion in healthy people. It has been shown that patients with bloating have impaired intestinal handling of gas loads due to impaired transit. This subtle motor dysfunction, which may lead to impaired propulsion and abnormal distribution of intraluminal contents, may explain the bloating, particularly in these patients who also have gut hypersensitivity and increased perception. 2)Reflexes also play a part in the transit of gas. Mild rectal distension provokes a reflex that leads to increased transit of gas in healthy people but not in IBS'ers.3)Retention of gas takes place by increased resistance to gas flow for exammple voluntary tightening of the anal spinchters and impaired intestinal propulsion. But regardless of anal function patients with bloating retain gas. In summary What has been discovered so far about abdominal distension and intolerance to gas loads:Abdominal distension depends on the volume of gas retained. But abdominal discomfort appears to derive from failure to propel gas, possibly because of uncoordinated intestinal motility rather than weak propulsion because studies have shown that weak propulsion leads to painless distension. It has been shown that the slowing effect of lipids is increased in patients with discomfort, whereas the prokinetic effect of distension is impaired markedly. The fact that neostigmine reduced gas retention and improved abdominal distension and symptom perception suggests that abnormal gas transit or perception of intestinal gas was responsible for the abdominal symptoms.Fourther studies have shown that there is impaired small intestinal propulsion but colonic transit is normal. Other possibilities"The hypothesis that abdominal bloating is caused by intestinal gas intolerance is attractive. Other possibilities, however, must be contemplated. For instance, individuals with increased gas production who are unable to evacuate gas because of anal incoordination and functional outlet obstruction may retain gas in the colon and eventually become symptomatic, and the same would apply to individuals who retrain gas evacuation because of social constrictions. Furthermore, functional dyspepsia frequently is associated to IBS, and in these patients postprandial bloating may originate in the stomach rather than in the intestine [7], [8]. These patients exhibit impaired meal accommodation of the stomach and increased gastric perception [8]. Thus, increased tension of the hypersensitive gastric wall, but not intestinal gas, may be the cause of dyspeptic bloating."THE POTENTIAL ROLE OF ABDOMINAL MUSCULAR ACTIVITYSome studies have measured girth changes in relation to bloating, and the results indicate that overall abdominal distension can be objectivated. Is the abdominal wall response the same in patients as in healthy subjects, however? A dystonic abdominal wall(that repeatedly contracts) could fail to support adequately intra-abdominal contents and make the patient feel bloated, particularly in the erect position. Protrusion of the abdominal wall can be produced by a redistribution of abdominal contents without net increments in intra-abdominal volume.
 

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I found this very interesting, and what I understand I believe to be true for myself. I often feel as though the only comfortable feeling would require practically nothing between my abdominal wall and my backbone!I almost always have distention with bloating. It's like my whole abdomen is a large mass. It's too firm to be fat and too poochy to be muscle.I have to push against my abdomen with my arm to get any gas out. Sometimes my abdominal muscle is tense, and I have to push a lot harder than others. I cannot recall having ever expelled gas involuntarily! Now I can only expel twice a day when I am comfortably on my toilet pressing and pushing. Usually those two times are pretty heavy explosions. So I can see where the "irregualar distribution" thing comes in.I'm sure my daily use of milk of magnesia over the past 8 years has had something to do with my feelings, but, for me, it beats the bloating and distention from no colon activity.Thanks for posting this article!
 

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Discussion Starter · #3 ·
quote:I cannot recall having ever expelled gas involuntarily!
Yes they have found that people who control the evacuation of gas as needed by the tightening of the anal sphincter due to social constrictions or otherwise (like lack of anal coordination) suffer more from the discomfort associated with bloating. Perhaps the trick is to let more gas out as the need arises but that is like leaping out of the frying pan into the fire if it causes social embarassment? Probably ask to be excused more often?.BTW AD I remember you from the past. Hope you are doing ok?
 

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I've been away from the boards while college was going on. Just a minimum full-time course load with no job takes up every second of my time. I probably spent a total of five or six hours in the bathroom each day. Thanks for asking!I really can't discern all the different muscles down there. It all feels like the same muscle to me. I've never really had any indication of needing to expel any gas, so I haven't had anything to try to "hold in." Only when I go to the bathroom from the milk of magnesia, and only after sitting on the commode manually squeezing my abdomen for a few minutes does gas (or much anything) come out. The gas seems to come out in large, dense lumps that feel like rocks to me.The bloating and occasionally distention sometimes actually feels worse after expelling the gas and/or liquids, often accompanied by this annoying little round vibration somewhere in the abdomen. It's like a bubble of compressed air is being popped open within my colon. I often just wish I could smash the whole thing flat with an anvil like Wile E. Coyote and the roadrunner.
 

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bonniei: what does this mean?"It has been shown that the slowing effect of lipids is increased in patients with discomfort, whereas the prokinetic effect of distension is impaired markedly."Lipids move more slowly? What, exactly, are they and in what medium do they move? (I believe they are one of the "things" measured in my cholesterol test; however, I have always just looked at the numbers to see how I am doing, rather than inquiring about what comprises them.) Thanks.Getting old, now...hardly understand the language, anymore.Mark
 

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Mark, I think that the composition of a meal can effect how it moves through the GI tract. So a fattier meal, if I recall correctly, moves along at least some parts of the GI tract more slowly than a less fat meal.Lipids are fat. Whether you eat it or it is running around in the blood.K.PS. They just talked about blood lipids testing on TV. A lipid profile tests how much of which kinds of cholesterol and triglycerides you have in the blood.
 

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Thanks, Kath.So a fattier meal would transit more slowly, allowing more gas to develop (in those of us so inclined) and more cholesterol to be absorbed? This would explain why I produce more gas after more traditional North American fare then with rice and veggies, pastas, fish, etc.The manufacturer of Provex has introduced both fiber and now probiotics to their heart supplement packages. I was curious what role "our" digestive products would play in heart health. This goes a long way to explaining that. It also would suggest that for those on the C side, here, a lowering of cholesterol would be even more important than for the rest of us, as C would allow even more to be absorbed. While it is not the link I think exists between brain blockages and IBS it does suggest at least a causal relationship from IBS to cardiovascular disease. (Turning 60 this week, blood pressure, body fat and cholesterol all normal to low. Not too bad for the fat old Ibeezer who was on his way to the glue factory a few years ago, eh?)Mark
 

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I'm not sure how long the slower transit is (and I haven't reviewed the whole article to get the context fully)Usually I think this is more in stomach/small intestine slowness. On of the ways to slow down digestion of refined carbs is to add some fat to it (like butter or olive oil on bread) with bloating this may be more of a stomach/upper GI bloating issue (that I feel too full after I eat for too long...maybe more than I have gas that fills me up and when I fart it out I feel less bloated) bloating.I'm not sure how fat in the meal effects absorbtion of cholesterol (I'm not clear if high fat diets make you absorb more cholesterol or make your body make more cholesterol, but I thought it was more along the lines of you make more, not you absorb more).I'm not sure how transit through colon would effect gas production (I mean if it is 16-60 hours what is an additiona hour) but the slow down in the upper GI could be a big factor in upper abdominal bloating.K.
 

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The phytostereol/omega 3 combo that I am taking blocks the cholesterol receptors in the digestive system for the period that the meal passes by, which has given me the same reduction in numbers that the statins do in lowering the liver production. From "elevated" to "low" in 2 months time! (This is the same process as in the JAMA study that I think you cited, that recommended okra, among other veggies, in reducing cholesterol.) I do not know where in the digestive system those receptors lie; but I expect they are pretty high in the small intestine, as the supplement is taken just prior to eating and apparantly survives the digestive process longer than the food takes to pass by. Thus, transit time would be an issue. I suppose my gas problem must also derive from my stomach or upper intestine, as with certain meals, especially meats, it smells slightly of what I have just consumed. The bloat (not of pregnancy size) occurs below the stomach and is relieved by the fart, to build again. It often seems like an allergic response, as the gas will carry on for some hours in some cases, briefly in others. The longer the effects, the fouler the odor; but it never lasts more than about 8 hours (and very seldom that long, any more).Mark
 

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quote:So a fattier meal would transit more slowly, allowing more gas to develop (in those of us so inclined)
First, excess gas seems to be a rare problem.Second, a high fat meal might actually reduce gas production by slowing down the transit of carbohydrates to the colon giving them more time to be digested and absorbed in the small intestine.
quote:and more cholesterol to be absorbed?
Fats themselves are fully absorbed. Cholesterol should be as efficient.
quote: I do not know where in the digestive system those receptors lie; but I expect they are pretty high in the small intestine,
Absorption takes places mostly in the middle of the small intestine, known as the jejunum.
quote:I suppose my gas problem must also derive from my stomach or upper intestine, as with certain meals, especially meats, it smells slightly of what I have just consumed.
It's not. Gas in the gut is produced solely in the colon.
quote:It often seems like an allergic response
Gas production in the gut, which means in the colon, is not related to allergy of any kind.
 

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Thanks for the digestive info. It helps to know how these things work. I don't know how it happens, but yesterday I had a quick grilled cheese sandwhich before taking my dog to the vet. 15 min later, as I was about to enter the vet's office, I farted cheese.Eggs and meat will both bring on similar quick response and peanuts will cause sustained reactions for hours if I overindulge. Whatever the cause it is certainly dramatic.Mark
 

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quote:It's not. Gas in the gut is produced solely in the colon.
Acutally, I should qualify this..Bacterially derived gas is produced solely in the colon.Carbon dioxide is produced in the duodenum from acid-base neutralization. If one were producing a lot of acid, that would lead to more CO2 being produced, but generally, CO2 is absorbed as it's being produced and doesn't impact much on gas in the gut.
 

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Discussion Starter · #13 ·
overitnow bloating after fat has been well documented by a bunch of Spanish scientists, Serra et al. Apparently it lead to more gas retention rather than production. I was just trying to clarify Kath's quote
quote:with bloating this may be more of a stomach/upper GI bloating issue (that I feel too full after I eat for too long...maybe more than I have gas that fills me up and when I fart it out I feel less bloated) bloating.
If you let it out you would feel better but the problem might be that you can't let it out since IBS'ers don't have the ability of normal people. There is a reflex that rectal distension should lead to accelerated transit of gas but that reflex is impaired in IBS'ers.
 

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The upper GI bloating I get is not a matter of letting out farts out or not. or being able to let out farts or not.It isn't related to gas or needing to fart as best as I can tell.I do get some bloating that is needing to fart related and it is very different from the upper GI I feel like I ate a whole cow after eating 4 bites of a sandwich and I feel that way for 3-6 hours after the meal with no relief from any sort of gas removal from the body.I tend to think that over-full indigestion type of bloating may be more of the fat slows thing down sort of bloating.Much more than my colon is full of gas and farting it out makes me feel better bloating that I have also had.K.
 

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Discussion Starter · #15 ·
When fat is added it leads to retention of gas in the small intestine in IBS'ers according to Serra. I think perhaps in people with dyspepsia and IBS it is more a gastric thing.Quote from the article I posted at the top of this thread
quote:Furthermore, functional dyspepsia frequently is associated to IBS, and in these patients postprandial bloating may originate in the stomach rather than in the intestine [7], [8]. These patients exhibit impaired meal accommodation of the stomach and increased gastric perception [8]. Thus, increased tension of the hypersensitive gastric wall, but not intestinal gas, may be the cause of dyspeptic bloating."
 
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