Scientific Publications
Roles for dietary fibre in the upper GI tract: The importance of viscosity
Food Research International, 135, 73-80
Dietary fibre has long been recognised as healthy because of its prebiotic quality and a number of dietary fibres,especially beta glucan have been shown to lower levels of circulating LDL cholesterol. However, although EFSAallow health claims to bemade for this, there is no fundamental understanding of the detailedmechanism involved.More recently dietary fibre has been shown to have a range of functionality in the upper GI tract. The presence offibre can alter gastric emptying thus affecting fullness and satiety. These alterations are a result of differences inviscosity, nutrient release and nutrient sensing in the duodenum. The current proposed mechanisms for the cholesterollowering effects involve disruption of the normal recycling of bile possibly by sequestering bile salts and fattyacids or by significantly decreasing the rate of absorption as a result of entanglement with intestinal mucus.The use of quantitative confocal microscopy methods such as fluorescence recovery after photobleaching (FRAP)and multiple particle tracking has provided evidence that dietary fibre can combine with intestinal mucus andproduce a layer that significantly delays the transport of lipid digestion products. We have also used similarmethods in conjunction with more conventional rheology to showthat DNA fromthe gut epitheliumcan contributesignificantly to the barrier properties of the intestinal mucus layer.The delay in the transport of nutrients to the gut epithelium has implications for the control of gastric emptyingand through secretion of GI hormones such as CCK and thus for the satiating ability of foods. It may also haveimplications for the reabsorption of bile.
Food Research International, 135, 73-80
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