Bile acid binding by dietary fiber-mineral complexes in the rat

After observing enhanced binding of deoxycholic acid to dietary fiber-mineral complexes in vitro, this study focused on the ability of dietary fiber-mineral complexes to bind bile acids in vivo. The binding and removal of bile acids from the enterohepatic cycle may decrease liver cholesterol levels and the risk of colon cancer. Psyllium and locust bean gum were gavaged at 100mg with or without the addition of iron or calcium (100% USRDA/4g fiber). Cholestyramine was used as a positive control, and solka floc W-40 was used as a negative control. 0.2uCi of $\sp{14}$C-deoxycholic or cholic acids were duodenally injected 15 minutes post-gavage. Twenty-four hour fecal collections were assayed for $\sp{14}$C-bile acid activity. Psyllium-iron was found to bind more deoxycholic (8.1% $\pm$ 1.5; p $\le$ 0.36) and cholic (10.1% $\pm$ 1.3; p $\le$ 0.017) acids than psyllium alone (6.5% $\pm$ 0.9 and 5.3% $\pm$ 1.3, respectively). No significant differences were seen between locust bean gum with or without the addition of minerals. Cholestyramine bound more deoxycholic and cholic acids than any of the dietary fibers or dietary fiber-mineral complexes (28.8% $\pm$ 2.0 and 20.7% $\pm$ 2.9, respectively). No significant differences were observed between single (100mg) and double gavages (200mg) for the psyllium or psyllium-iron. It appears that dietary fiber-mineral complexes can withstand in vivo conditions. Dietary fibers supplemented with mineral(s) may offer a suitable alternative to cholesterol lowering drugs, such as cholestyramine. In the future other dietary fiber combinations may be evaluated on both deoxycholic and lithocholic acids