Mineral Dietary Supplement To Decrease Cadmium Relative Bioavailability in Rice Based on a Mouse Bioassay

Abstract

To determine the effectiveness of mineral dietary supplements to modulate cadmium (Cd) exposure, an in vivo mouse bioassay was conducted to determine Cd relative bioavailability (Cd-RBA) in Cd-contaminated rice (0.80 mg Cd kg) with and without Zn, Fe, or Ca supplements as nitrate or chloride salts. Without mineral supplements, Cd-RBA was 43 ± 5.3% based on average Cd accumulation in the liver plus kidneys as the end point. Among Ca(NO), Zn(NO), and Fe(NO) supplements, 150-5000 mg kg Ca was the most effective in reducing rice Cd-RBA by 31-80% to 8.5-29%, while 30-200 mg kg Zn supplements was ineffective, with Cd-RBA being 33-57%. Low Fe at <40 mg kg had little impact on rice Cd-RBA (39-47%), while high Fe at 80-200 mg kg decreased Cd-RBA by 37% to 26-27%. The ineffectiveness of Zn supplements in reducing Cd-RBA was probably due to coinciding 8.3- and 3.1-fold increases in Zn accumulation in mouse kidneys and liver with Zn supplements, while Ca and Fe supplements led to much-smaller increases in Ca and Fe accumulation in mouse tissues (1.3-1.6 fold). In addition, compared to Ca(NO) supplements, Cd-RBA values determined with CaCl supplements were significantly higher (25-67% versus 8.5-29%), suggesting that chloride enhanced Cd-RBA. Results of this study have important implications for developing effective dietary strategies to reduce dietary Cd exposure and the associated health risks in humans.

In Vitro and In Vivo Testing to Determine Cd Bioaccessibility and Bioavailability in Contaminated Rice in Relation to Mouse Chow

“…Similarly, in rats fed rice diets, adequate intake of Fe and Ca combined caused a 6-fold decrease in Cd absorption compared to that in rats consuming the same marginal minerals [19]. The finding from Zhao et al [38] also confirmed our result that increased dietary levels of Ca and Fe significantly decreased relative bioavailability of Cd in rice. Moreover, Europeans and Americans who consume a variety of garden foods containing higher Zn, Fe, and Ca along with Cd have lower Cd absorption [21].…”

An interventional study of rice for reducing cadmium exposure in a Chinese industrial town

“…The main local vegetable for this study population was cabbage, which is high in Calcium (29,867 ± 1725 mg/kg) (Li et al, 2018). Calcium is notably effective in reducing the relative bioavailability of rice Cd; 150–1500 mg/kg Ca could reduce rice Cd bioavailability by 8.5–80% (Zhao et al, 2017). The noticeable decrease of UCd from June to September in the Int group can be due to change in consumption of high-Cd home-grown rice to low-Cd market rice.…”

Protective Effects of Moderate Ca Supplementation against Cd-Induced Bone Damage under Different Population-Relevant Doses in Young Female Rats

“…In experimental animals, the effects of the interactions between Ca and Cd create a complex effect on bone health because different levels of exposure to Cd and Ca have different toxicokinetic characteristics [15,16,17]. However, many previous experimental animal studies have employed Cd doses larger than doses received by humans in the general population (i.e., in unpolluted areas) [17,18,19,20]. In addition, excess Ca in the body is a risk factor for kidney stone formation, impaired absorption of other minerals, and increased cardiovascular events [21,22].…”

“…In addition, excess Ca in the body is a risk factor for kidney stone formation, impaired absorption of other minerals, and increased cardiovascular events [21,22]. Similarly, previous studies concerning the protective effect of Ca against Cd-induced toxic effects have also used Ca doses higher than the dose considered to be the adequate intake level in humans, and even higher than the tolerable upper intake level [17,18,19]. Also, the intake of the tolerable upper intake level is not a recommended level of intake [17].…”

“…Similarly, previous studies concerning the protective effect of Ca against Cd-induced toxic effects have also used Ca doses higher than the dose considered to be the adequate intake level in humans, and even higher than the tolerable upper intake level [17,18,19]. Also, the intake of the tolerable upper intake level is not a recommended level of intake [17]. Taking the above into account, it seems crucial to consider the risk of potential adverse health effects of Ca supplementation in the antagonism of Cd-induced bone damage.…”