Dietary fibre on cell proliferation in large bowel mucosal crypts near or away from lymphoid nodules and on mineral bioavailability

The effect of consumption for 24 weeks of different amounts (0%, 5% or 10% w/w) of fermentable (pectin and guar gum) or nonfermentable (cellulose and lignin) dietary fibres on cell proliferation and other parameters in large bowel mucosal crypts was studied in rats. In all 12 dietary groups, the cry pts located over the distal aggregate of lymphoid nodules (ALN) had more co lchicine arrested metaphase figures per midaxial crypt section (MC) and a l onger crypt column height than crypts located three to four cm away from th is ALN. These differences are attributed to the tropic influence of nodular cells in the ALN. Consumption of fermentable fibre decreased pH in the lum en of the caecum, and glucose, Zn and Cu in serum but increased Ca and Mg i n serum. The decrease in caecal pH and serum glucose was significantly corr elated with a decrease in MC. Increased intake of the nonfermentable fibre types increased faecal bulk but had no significant correlation with the oth er measured crypt parameters. Multiple regression analyses was used to mode l the relationships between the mucosal crypt criterion variables and the t wo measured predictor variables, caecal pH and serum glucose. Relationships between dietary fibre, ALN, MC, bioavailability of dietary minerals and ri sk of colorectal cancer are discussed.