Abstract
There are controversial results for the effects of dietary fiber intake on zinc absorption. In the present study, we examined the effects of five refined water soluble dietary fibers with different physical and chemical properties on zinc absorption in rats. Sprague-Dawley male rats, weighing 50 g, were acclimated and fed a basal diet (control) or five test diets containing 50 g/kg diet fiber sources, arabinogalactan, partially hydrolyzed guar gum (GGH), carboxymethyl cellulose (CMC), psyllium and guar gum for 3 weeks. There was no difference in body weight and food intake among the six groups of rats. Apparent zinc absorption (rates and amounts) for 3 days from Day 8 and Day 18 after the starting test diets were lower in rats fed CMC compared with the control group. In later test period, zinc absorption was lower in the psyllium group than the two low viscous fibers, ara binogalactan and GGH-fed groups. However, high viscosity may not be involved in lowering zinc absorption because the absorption in rats fed guar gum, the highest viscous fiber, was not lower than in rats of the control group. Changes in femur zinc concentration among the groups were similar to the changes in the zinc absorption. In conclusion, CMC ingestion was clearly lowered zinc absorption, but other four soluble fibers were not.
