Cadmium in wheat grain: its nature and fate after ingestion

Cadmium intake in humans derives primarily from vegetable foods, yet the extent to which the chemical form and dose of cadmium in such foods influences the fate and toxicity of this metal is poorly understood. We have compared the fate in mice of trace levels--approximating that in agriculturally produced grain--and high levels of cadmium supplied as wheat grain with that of cadmium supplied as CdCl2. The amounts and forms of the metal in kidney and liver, target organs in cadmium accumulation, were compared. Results indicate that, in mice, cadmium orally administered as grain and that as CdCl2 have a similar fate in terms of organ distribution and the nature of the Cd-forms in kidney and liver. A low dose of either form resulted in higher kidney versus liver cadmium. Preliminary characterization studies indicate that cadmium in wheat grain occurs primarily as an 11,000-dalton, aqueous-soluble complex, which is not inducible by cadmium.