There is no healthy level of cadmium but since it accumulates in humans over time, 'normal levels' have been established. Blood cadmium should be less than 5.0 ng/mL. Acute toxicity is observed when blood levels exceed 50 ng/mL. Cadmium exerts its toxicity by mimicking essential metals. When cadmium is present it can displace zinc, calcium, and iron in proteins and enzymes, causing widespread dysfunction in cells and tissues. Cadmium increases oxidative stress by being a catalyst in the formation of reactive oxygen species, increasing lipid peroxidation, and depleting glutathione and protein-bound sulfhydryl groups. Cadmium also can stimulate the production of inflammatory cytokines.
Low-level exposure among the general population produces few early physical findings on examination. Acute toxicity from high levels of exposure can present with shortness of breath as well as renal failure, kidney stones, and sometimes skeletal lesions. When ingested, cadmium can resemble food poisoning with vomiting, abdominal cramps, and diarrhea.
