Increased dietary cadmium absorption in mice and human subjects with iron deficiency.

In mice fed a low iron diet, the addition of low levels of cadmium chloride (10 micrometer) to the drinking water impaired growth and accentuated the development of anemia. Cadmium had no effect on mice given a similar diet supplemented with iron. Iron deficiency increased the concentration of cadmium in the duodenal mucosa, the transfer of cadmium to the body from the intestinal tract, and the deposition of absorbed cadmium in the kidneys. In human subjects, the average absorption of 25 microgram of cadmium, labeled with 115mCd, from a test meal was 8.9 +/- 2.0% (mean +/- SE) in 10 people with low body iron stores (serum ferritin less than 20 ng per ml) and 2.3 +/- 0.3% in 12 subjects with normal iron stores (serum ferritin greater than 23 ng per ml). The biological half-time of the radiocadmium in 3 of the subjects ranged from 90 to 202 days. Thus, the intestinal adaptive response to iron deficiency in both experimental animals and human subjects leads to the increased absorption of cadmium, a potentially toxic element.