Accumulation of cadmium from wheat bran, sugar-beet fibre, carrots and cadmium chloride in the liver and kidneys of mice

Abstract

The gastrointestinal absorption and organ distribution of Cd after exposure for 9 weeks to three fibre-rich foodstuffs (wheat bran, sugar-beet fibre and carrots) were determined in mice. Groups of eight mice were given a diet containing 0·05 mg Cd/kg from wheat bran, sugar-beet fibre, carrots or CdCl 2 mixed in a semi-synthetic, low-Cd (<0·007 mg/kg) feed. A control group was fed on the low-Cd semi-synthetic feed. The water consumption, food consumption and the weight of the animals were monitored throughout the study. The feed was changed once weekly and Cd was analysed in the feed at each change. myo-Inositol phosphates (hexa-, penta-, tetra-and tri-) and Zn, Cu, Fe and Ca were also analysed in the diets. After 9 weeks, the mice were killed and liver and kidneys were sampled and analysed for Cd. The group receiving the wheat-bran diet had significantly lower fractional Cd accumulation (% total Cd intake) in the liver and kidneys than the other groups, indicating a lower fractional absorption of Cd. The wheat-bran diet had markedly higher levels of inositol hexa-and pentaphosphates (phytates) and a Zn level that was twice as high as those in the other diets. The higher levels of myo-inositol hexa-and pentaphosphates in the wheat-bran diet most probably contributed more to the lower fractional absorption of Cd than the elevated Zn level, due to the formation of insoluble Cd-phytate complexes. Compared with the wheat-bran diet, the sugar-beet-fibre and carrot diets contained very low levels of myo-inositol penta-and hexaphosphates, and consequently the fractional Cd absorption from these diets was higher.

Accumulation of Dietary Cadmium (Cd) in Rabbit Tissues and Excretions: A Comparison of Lettuce Amended with Soluble Cd Salt and Lettuce with Plant-Incorporated Cd

“…Several studies addressing this question have used grain-based diets, and these reports generally concur with our observation (Chan et al, 2000) that Cd incorporated into grain was accumulated similar to Cd added to grain (Moberg Wing, 1993;Lind et al, 1998), unless bran, from which Cd is less readily accumulated by the target organs, was included in the diet. Lind et al (1998) pointed out that bran often accounts for much of the phytate found in grain, and phytates are notoriously insoluble to digestion: It has been speculated that bran Cd might be mostly associated with phytate. If Cd phytate is absorbed less readily by the intestinal mucosa, or does not induce Cd-MT production, either of these could result in lower accumulation of Cd in the kidney.…”

Comparative effect of water and food-chain mediated cadmium exposure in rats

“…b Feed intake was measured only for rats exposed to Cd in diet (controls were pairfed) c Cd intake of rats exposed to Cd in water and diet was calculated on the basis of the concentration of Cd in drinking water (0.3 mg Cd/l) and diet (0.4 mg Cd/kg), respectively 2002). This accounts for the use of Cd load in the liver and kidneys in the estimation of Cd uptake in the present study which is also in harmony with previous reports (Andersen et al 1992;Crowe and Morgan, 1997;Reeves and Vanderpool 1998;Lind et al 1995;Lind et al 1998). Thus the significantly (P \ 0.05) smaller combined Cd load of the liver plus that of the kidney of rats exposed to Cd via the experimental food-chain relative to those exposed to the element in drinking water for the same exposure periods (Fig.…”

Trace metals in soft and durum wheat from Italy

“…Nevertheless, cadmium in the ® bre-rich fractions of wheat seems to be poorly bioavailable, due to the presence of high levels of zinc and phytates. A decrease in fractional absorption and accumulation of cadmium has been recorded in rats and mice fed with whole wheat grains or wheat bran with respect to other diets, the main reason being probably the formation of insoluble cadmium-phytate complexes (Moberg Wing 1993, Lind et al 1998.…”