Bioavailability of Copper Bound to Dietary Fiber in Mice and Rats

Abstract

The bioavailability of copper (Cu) was compared in mice or rats fed diets containing wheat bran‐bound Cu and adequate Cu (unbound) or deficient Cu with cellulose or wheat bran. Cardiac and hepatic Cu content were comparable in mice fed bran‐bound or adequate Cu and greater than mice fed deficient Cu. Cardiac Cu content was comparable in rats fed bran‐bound Cu and adequate Cu and greater than rats fed deficient Cu. Hepatic Cu content, however, was less in rats fed bran‐bound Cu than adequate Cu and greater in both than deficient Cu. Both rats and mice utilized dietary Cu bound to wheat bran, suggesting that mineral‐fiber interactions may not decrease bioavailability when dietary mineral is adequate. Tissue Cu content in Cudeficiency was lower in animals fed wheat bran compared to cellulose, suggesting that the type of fiber may exacerbate effects of mineral deficiency.

Binding capacity of 18 fiber sources for calcium

“…The total binding capacity of a material was determined by weighing a 10-g sample of acid-washed fiber mixed with a 1 M calcium chloride solution in a ratio of 1:100 w/v. The slurry was mixed on a shaker over night in acid-washed bottles (Rockway et al, 1987). The slurry was filtered and repeatedly washed with distilled deionized water (pH = 7) and then freeze-dried.…”

Dietary Fibre and Mineral Bioavailability

“…The bioavailability of Cu in the presence of dietary fibre was studied in mice and rats by Rockway et al (1987). The following diets were tested: (1) wheat-bran-bound Cu, (2) adequate Cu (unbound), (3) deficient Cu with cellulose and (4) deficient Cu with wheat bran.…”

Factors Affecting Copper Absorption in Humans and Animals

“…Turnlund found no effect of phytic acld or cellulose (Turnlund et al, 1985) on Cu absorption In humans. Although wheat bran has been reported to depress eu bioavailability in rats and mice (Rockway et al, 1987), the high percent Cu absorption values observed in my laboratory from a diet containing 8 slices of whole-wheat bread/day (Table 3) argue against depression of Cu bioavailability in humans. AscorbIc acid (Jacob et al, 1987) did not affect Cu absorption in humans.…”