Cadmium Sources and Toxicity

Abstract

Cadmium is an environmental toxicant with high toxicity potential due to its non-biodegradability, coupled with high rates of soil-to-plant transference. It is estimated that 40–60% of dietary cadmium intake in the average consumer comes from dietary staples, such as rice, potatoes, and wheat, while shellfish, crustaceans, molluscs, offal and spinach form the remaining dietary sources. The divalent metal transporter, DMT1, the primary iron transporting protein in the intestine, is a major cadmium carrier, while ferroportin1 (FPN1) may mediate the transport of cadmium into the circulation. DMT1 expression is heightened in people with low body iron stores and iron deficiency; conditions common in women of reproductive age and children, rendering them at greatest risk of cadmium toxicity due to enhanced cadmium uptake. Chronic dietary cadmium exposure has been associated with increased risks of numerous diseases, including chronic kidney disease, hypertension, heart disease, osteoporosis, type 2 diabetes, liver inflammation, hearing loss, depression, macular degeneration, obstructive lung disease, infection with HBV and H. pylori, breast cancer, lung cancer and death from cancer and Alzheimer’s disease. These data signal that current population exposure levels have exceeded toxicity thresholds in many tissues, but the therapeutically effective metal chelating agents for reducing toxic Cd body burden are currently lacking.