Patients with BAM have reduced serum FGF19 which may be useful in diagnosis. We propose a mechanism whereby impaired FGF19 feedback inhibition causes excessive bile acid synthesis that exceeds the normal capacity for ileal reabsorption, producing bile acid diarrhea.

Increased TRPV1 nerve fibres are seen in quiescent IBD with IBS-like symptoms together with a correlation to pain severity. TRPV1 may contribute to the pathophysiology of ongoing pain and visceral hypersensitivity in this group of patients, providing a potential therapeutic target.

Gravimetric measurement of dietary fiber (DF) gives no indication of the biological function of any particular fiber. This study describes simple methods based on dialysis and fermentation that enable a hierarchy of fibers to be described for each of the major actions of fiber along the gastro-intestinal tract: nutrient absorption, sterol metabolism, cecal fermentation, and fecal bulking. These results were compared with previous metabolic studies with the same fiber isolates in humans. DF that modifies nutrient absorption can be identified by using dialysis studies, whereas identifying DF that modifies sterol metabolism, cecal fermentation, and fecal weight requires formulas that incorporate dialysis and fermentation results. Results from dialysis and fermentation predicted the action of wheat bran, pectin, guar, gum arabic, carboxymethylcellulose, gellan, tragacanth, xanthan, and karaya in humans and generated anomalous results for karaya and tragacanth. These methods could form the basis of techniques that would enable a screening of novel and processed fibers before studies in animals, including humans.

SUMMARY BackgroundBile acid diarrhoea is a common, under-diagnosed cause of chronic watery diarrhoea, responding to specific treatment with bile acid sequestrants. We previously showed patients with bile acid diarrhoea have lower median levels compared with healthy controls, of the ileal hormone fibroblast growth factor 19 (FGF19), which regulates bile acid synthesis.

SUMMARY In this paper aspects of the variability of methane producing status have been examined, and a survey of breath methane excretion in various clinical and control populations is reported. Prevalences of methane excretion were 54% in healthy controls, 53% in non-gastrointestinal patients and 32% in gastrointestinal patients. Patients with Crohn's disease, ulcerative colitis, and pneumatosis cystoides intestinalis had significantly lower prevalences of methane excretion (13%, 15%, and 11% respectively). Faecal constituents and in vitro incubation analysis were similar in breath methane excretors and non-excretors. Several patients did not excrete methane in the breath although methane was present in colonic gas. The results indicate that different gastrointestinal patient groups have different prevalences of breath methane excretion and that all healthy subjects may produce methane but only when the production reaches a threshold does it appear in the breath.Methane and hydrogen are produced during anaerobic bacterial activity in the large intestine and are excreted in flatus and expired breath. Human intestinal tract fermentation produces hydrogen, but methane is neither a universal constituent of colonic gas nor of expired breath.1 2