Influence of cereal bran supplement on cadmium effects in growing rats

Abstract

<jats:p> Strategies to diminish cadmium (Cd) absorption are highly desirable especially where Cd exposure due to environmental contamination is still inevitable. Cd toxicity may be influenced by dietary components, such as fiber and minerals. Multimixtures are low-cost cereal bran supplements used in Brazil and in other countries to counteract malnutrition in low-income populations. This study was aimed at evaluating whether multimixture would reduce Cd effects in young rats. Animals received a diet with or without the multimixture plus 0, 5, or 25 mg Cd/kg (control, Cd-5, and Cd-25 groups) during 30 days. The Cd-5 groups were similar to control groups in all parameters analyzed, except in the higher renal Cd concentration. However, the Cd-25 groups had lower biological growth parameters and renal δ-aminolevulinate dehydratase activity, besides higher renal Cd concentration and plasma alanine aminotransferase activity compared to the controls. The multimixture did not prevent Cd effects in the Cd-25 group, but caused a small reduction in renal Cd concentration in the Cd-5 group. Although this multimixture was ineffective to prevent Cd effects at the higher concentration, it seemed to reduce Cd accumulation at the lower Cd dietary concentration, which is similar to levels of human exposure in some polluted areas. </jats:p>

Effect of wheat bran and flaxseed on cadmium effects and retention in rats

“…Thus, it is possible that when the Cd concentration is increased (as in the present study), the metal exceeds binding capacity of fibers and the fiber effect is not detectable. Considering the effects of wheat bran and flaxseed found in the present study, as well as our previous results on fiber-rich cereal bran supplement, 45 we propose that two mechanisms may contribute to the effect of a dietary fiber source on Cd retention, leading to opposite results. Cd binding by fiber sites (most important for insoluble fiber sources that are less fermentable) would decrease metal absorption, while the acidification caused by fiber fermentation in the large bowel (most important for soluble highly fermentable fiber sources) would increase metal absorption.…”

“…7,43,44 We recently demonstrated that a fiber-rich cereal bran supplement reduced renal Cd accumulation when the metal was added to the diet at 5 mg/kg but not at 25 mg/kg. 45 Considering these results, we propose that the wheat bran fiber sites available to bind Cd are limited and may have been saturated at low Cd concentrations. Thus, it is possible that when the Cd concentration is increased (as in the present study), the metal exceeds binding capacity of fibers and the fiber effect is not detectable.…”

The Late and Persistent Pathogenic Effects of Cadmium at Very Low Levels on the Kidney of Rats

“…Renal accumulation of Cd in animals or humans exposed to chronic Cd has been extensively reported (Bernard 2004;Callegaro et al 2010;Koizumi et al 2008;Takaki et al 2004;Zager 2005). Groten et al (1991) have demonstrated that rats were fed with diets containing Cd as CdCl 2 either at 30 mg/kg that contributed a daily intake of Cd from 1-2.5 mg/kg body weight or at 1-8 mg/kg that contributed a daily intake of Cd from 0.13 to 0.26 mg/kg body weight for 4 weeks.…”

In vitro binding capacities of three dietary fibers and their mixture for four toxic elements, cholesterol, and bile acid

“…Dietary fibers can adsorb heavy metals [12,13] and act as a potential "functional food" that reduces the incidence of CVDs [9] by reducing the risk of type-2 diabetes, body weight, and serum lowdensity lipoprotein-cholesterol levels [14] and adsorbing bile acids. Bile acids, derived from cholesterol, are necessary for the digestion of lipids in the small intestine.…”