Effect of different dietary carbohydrates on colon function. Design of healthier foods

The overall objective of the project was to develop a scientific basis for recommending new dietary guidelines and for implementing the production of novel industrially-produced foods containing carbohydrates that have a protective effect on the colonic mucosa. In particular the project addressed the following aims: To investigate the patterns of SCFA formed by fermentation of a variety of complex carbohydrates by the human gut microflora in vitro. To assess whether a shift in the composition of the diet from simple sugars (e.g. sucrose) to complex carbohydrates (e.g. starch) has the potential to block steps leading to neoplastic transformation in the colon. To investigate, using human volunteers, animal models and in vitro methods, the possible mechanisms (including faecal concentration of short chain fatty acids, long chain fatty acids, bile acids, calcium, bacterial species) underlying the protective effects of selected complex carbohydrates, so that more effective carbohydrate sources can be developed. The work of the project fell under four main headings: 1. In vitro studies of carbohydrate fermentation by the human gut microflora 2. Animal studies designed to evaluate critically the potential protective role of complex carbohydrates, especially starches, in colon cancer 3. Dietary intervention studies in human volunteers to provide more definitive information on the protective effects of complex carbohydrates on colon damage in man. 4. Development and use of in vitro systems based on isolated colon cells in culture to investigate mechanisms involved and to identify gut luminal factors, particularly gut flora metabolites, with modulating activity towards cytotoxic and genotoxic damage in the gut. 98 Effect of different dietary carbohydrates on colon function. Design of healthier foods