Effects of FODMAPs on Small Bowel Water Content: an MRI Study

• small bowel water content area under the curve [ Time Frame: -45 min to 315 min ] [ Designated as safety issue: No ]
  Area Under the curve for small bowel water content, methods as Marciani, L., et al., Gastroenterology, 2010. 138(2): p. 469-U90. Hoad, C.L., et al.,. Physics in Medicine and Biology, 2007. 52(23): p. 6909-6922.
  
  

• gastric emptying T50 [ Time Frame: -45 min to 315 min ] [ Designated as safety issue: No ]
  time to half empty the stomach
  
  
• ascending colon volume [ Time Frame: -45 min to 315 min ] [ Designated as safety issue: No ]
  AUC of the geometric volume of the ascending colon
  
  
• ascending colon motility [ Time Frame: -45 min to 315 min ] [ Designated as safety issue: No ]
  motility index of the ascending colon as determined from dynamic MRI scan
  
  
• symptoms questionnaires [ Time Frame: -45 min to 315 min ] [ Designated as safety issue: No ]
  bloating, nausea, gas belching and abdominal pain
  
  
• bowel transit time [ Time Frame: 24 hours ] [ Designated as safety issue: No ]
  first time to detect sweetcorn markers in the stool
  
  
• fecal tryptase activity [ Time Frame: 24 h ] [ Designated as safety issue: No ]
  activity of stool triptase in trypsin units of activity
  
  

Title: Effects of FODMAPs (Fermentable Oligo-, Di-, and Mono-saccharides, And Polyols) on small bowel water content: an MRI study

1. Background. FODMAPs consist of fructose, lactose, fructo- and galacto-oligosaccharides such as fructans and galactans, and polyols such as sorbitol and mannitol. These carbohydrates are poorly absorbed in the small intestine and have been shown to trigger symptoms of irritable bowel syndrome (IBS). Previous studies have shown that fructose malabsorption results in an increased osmotic load in the small bowel, which can have a laxative effect. Physical proof of this has only been obtained using an ileostomy model on patients. This study indicated increased small bowel water content (SBWC) but this has never been established in intact humans .). We have been using noninvasive magnetic resonance imaging (MRI) to provide novel insights on the fate of food materials within the gastro-intestinal tract (GIT) of humans for the last decade.
2. Aims (to include hypothesis to be tested) This study aims to investigate whether fructose alone will increase SBWC compared to an equivalent mass of glucose, and if adding glucose to fructose will reduce its effect on the SBWC. The study also aims to determine if fructans alter colonic transit.The main hypothesis is that fructose will increase small bowel water while fructans will mainly affect colonic transit..
3. Experimental protocol and methods. A single-centre, randomized, cross-over design study consisting of a screening visit and four test days, which will be approximately 1 week apart The subjects (18 healthy volunteers for main study plus 4 for pilot studies) will receive (according to a randomization schedule) each test day one out of four test products: 1) glucose (control) 2) fructose, 3) glucose with fructose and 4) fructans. On each test day, volunteers will have a baseline scan in a 1.5T scanner, consume one of the products instead of breakfast at 09:00 and will be imaged in the scanner at intervals for 5 hours using a range of MRI sequences.

All the tested ingredients are food grade, have a history of safe use at intended usage levels, and are regarded as safe.

Four test products will be evaluated:

1. 500 mL of glucose (40g of glucose dissolved in water with pure lime juice as flavorant)
2. 500 mL fructose (40g fructose dissolved in water with pure lime juice as flavorant)
3. 500 mL of glucose with fructose (40g glucose and 40g fructose dissolved in water with pure lime juice as flavorant, 40 or 80 gm)
4. 500 mL fructan (40g of 100% fructan (inulin) dissolved in water with pure lime juice as flavorant)

4. Measurable end points/statistical power of the study. Primary endpoint: small bowel water content area under the curve (AUC) -45 - 315 minutes. Secondary endpoint: gastric emptying T50, colonic volume as characterised by AUC -45 - 315 minutes of ascending colon, colonic motility, symptoms questionnaires, small bowel transit time, breath hydrogen concentrations and tryptase faecal content.

Previous work using mannitol and glucose indicates that mean (SD) SBWC at 40 minutes postprandial after ingesting 300ml glucose was 47 (SD 15) and using n=12 the investigators calculate the investigators can detect an increase of 20 ml in excess of this with 90% power which is very much less than the investigators are predicting. The investigators plan to use 18 to ensure the investigators can assess our secondary endpoints for which there is no data with which to perform a power calculation.