| Intestinal Absorption of Dietary Cadmium in Women Depends on Body Iron Stores and Fiber Intake Marika Berglund, Agneta Åkesson, Barbro Nermell, and Marie Vahter Institute of Environmental Medicine, Karolinska Institutet, S-171 77 Stockholm, Sweden Abstract
Measurements of intake and uptake of cadmium in relation to diet composition were carried out in 57 nonsmoking women, 20-50 years of age. A vegetarian/high-fiber diet and a mixed-diet group were constructed based on results from a food frequency questionnaire. Duplicate diets and the corresponding feces were collected during 4 consecutive days in parallel with dietary recording of type and amount of food ingested for determination of the dietary intake of cadmium and various nutrients. Blood and 24-hr urine samples were collected for determination of cadmium, hemoglobin, ferritin, and zinc. There were no differences in the intake of nutrients between the mixed-diet and the high-fiber diet groups, except for a significantly higher intake of fiber ( p <0.001) and cadmium ( p <0.002) in the high-fiber group. Fecal cadmium corresponded to 98% in the mixed-diet group and 100% in the high-fiber diet group. No differences in blood cadmium (BCd) or urinary cadmium (UCd) between groups could be detected. There was a tendency toward higher BCd and UCd concentrations with increasing fiber intake ; however, the concentrations were not statistically significant at the 5% level, indicating an inhibitory effect of fiber on the gastrointestinal absorption of cadmium. Sixty-seven percent of the women had serum ferritin <30 µg/l, indicating reduced body iron stores, which were highly associated with higher BCd (irrespective of fiber intake) . BCd was mainly correlated with UCd, serum ferritin, age, and fiber intake. UCd and serum ferritin explained almost 60% of the variation in BCd. UCd was mainly correlated with age, fiber intake, cadmium intake, and serum ferritin, besides BCd. Age and fiber intake explained 22% of the variation in UCd. The results of the present study indicate that BCd mainly reflects body burden at long-term, low-level cadmium exposure. Key words : bioavailability, cadmium exposure, dietary exposure, duplicate diets, fiber intake, iron, vegetarianism. Environ Health Perspect 102:1058-1066 (1994) . http://ehpnet1.niehs.nih.gov/docs/1994/102-12/berglund.html Address correspondence to M. Berglund, Institute of Environmental Medicine, Karolinska Institutet, PO Box 210, S-171 77 Stockholm, Sweden. We acknowledge all the participating women. This study would not have been possible without their reliable cooperation. We also acknowledge Lena Johansson and Marie Nybäck for excellent assistance with sampling and analysis, Daniel Thorburn, Department of Statistics, University of Stockholm, for his suggestions on statistical analyses, and the Department of Occupational and Environmental Medicine, University of Lund, for reference analyses. This research was supported by the Swedish Environmental Protection Agency and Cerealia Research Fund. Received 19 April 1994 ; accepted 3 August 1994.
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