"Brain-gut does NOT explain it!!!!" Are you 100 percent proof positive sure about that? Or is it just your opinion?"The Pathophysiology of BloatingGas-Related MechanismsPatients and some physicians believe that excessive quantities of intestinal gas are the reason for bloating and/or distension. However, studies attempting to measure gas volumes have not consistently supported this theory. One such study, by Lasser and colleagues,[26] using a gas washout technique, found no differences in gas volumes between patients with bloating and their volunteer counterparts; several more recent studies using labeled sulfurhexafluoride have supported this finding.[27] Using CT scanning to estimate gas volumes, Maxton and colleagues[21] also found no definitive evidence of excess gas in IBS patients, despite demonstrating increased lateral abdominal profiles in these patients. In contrast, Koide and coworkers[28] used plain abdominal radiographs to show that gas volumes were greater in patients with IBS compared with controls. In another study, King and colleagues[29] found that although patients with IBS produced more hydrogen, total gas production was not significantly increased. Thus, the balance of evidence is against excessive gas being the sole cause of abdominal distension.An alternative approach to determining whether bloating/distension is related to excessive amounts of intestinal gas is to assess whether attempting to modify gas volumes alters the severity of these complaints. One such study administered lactulose, a fermentable fiber (psyllium), and a nonfermentable fiber (methylcellulose) to healthy volunteers. Although lactulose ingestion resulted in an increase in flatus, all 3 materials resulted in an increase in bloating. Gas production as measured by breath hydrogen concentrations only increased following lactulose. This interesting study suggests that whereas gaseous symptoms (ie, passage of flatus) are probably related to an increase in gas production, bloating may not be.[30] Another approach to altering gas production is the modification of colonic flora. Two studies found that treatment with antibiotics improved gastrointestinal symptoms other than bloating in patients with IBS thought to have bacterial overgrowth,[31,32] and another reported similar results in patients with functional gastrointestinal disorders without bacterial overgrowth.[33] Other studies using probiotics have also failed to demonstrate any improvement in bloating, although one study did report an improvement in flatus production.[34,35] Taken together, these studies also suggest that excessive quantities of intestinal gas may be associated with gas-related complaints (flatus volume and frequency), although not necessarily be related to the symptom of bloating.Accumulating evidence from the Barcelona group, headed by Professors Azpiroz and Malegalada, has suggestedthat while gas volumes may be normal in bloated patients, intestinal gas handling is abnormal.""Following a study validating their "gas challenge" technique (the gas challenge test involves infusing gas at 12 mL/min into the subject's jejunum, while recording symptoms, abdominal girth, and gas volumes) in healthy volunteers,[36] Serra and colleagues[27] found that during jejunal gas infusion, 18 of 20 IBS patients retained gas, had distention, or developed abdominal symptoms, whereas 16 of 20 healthy volunteers failed to do so. These changes could be augmented by enteral infusion of lipid, providing one possible rationale as to why bloating frequently worsens in the postprandial period.[37"
http://www.medscape.com/viewarticle/483079_4Sensation of bloating and visible abdominal distension in patients with irritable bowel syndrome." CONCLUSIONS: Bloating and visible abdominal distension may arise from two distinct but interrelated physiological processes. Although the sensation of bloating may be related to enhanced sensitivity to visceral afferent stimulation, abdominal distension in more severely affected patients may be related to triggering of a visceromotor reflex affecting the tone of abdominal wall muscles."
http://www.ncbi.nlm.nih.gov/entrez/query.f...947&query_hl=11A good percentage of IBSers find that bloating and distension worsen as the day progresses also and"including progressive worsening of symptoms during the day, and relief by passing stool or gas. Both bloating and distension worsened when other abdominal symptoms worsened. Abdominal distension was associated with greater symptom severity and less diurnal variation in symptoms, and was less often perceived as associated with food intake."The brain gut axis could explain abdominal bloating and distension.