| Cadmium Burden of Men and Women Who Report Regular Consumption of Confectionery Sunflower Kernels Containing a Natural Abundance of Cadmium Philip G. Reeves and Richard A. Vanderpool United States Department of Agriculture, Agricultural Research Service, Grand Forks Human Nutrition Research Center, Grand Forks, ND 58203 USA Abstract
Because of inherent genetic and physiological characteristics, the natural concentration of cadmium in the kernels of sunflowers grown in uncontaminated soils of the northern Great Plains region of the United States is higher than in most other grains. We tested the hypothesis that a habitual consumption of sunflower kernels will increase the body burden and health effects of cadmium in humans. Sixty-six men and women who reported consuming various amounts of sunflower kernels were recruited and divided by sex and kernel consumption: those who consumed less than or equal to 1 ounce(oz) /week and those who consumed more than 1 oz/week. Cadmium intake was assessed by calculation from 7-day food diaries, cadmium burden by whole blood cadmium, red blood cell (RBC) cadmium and urine cadmium concentrations, and health effects by urinary excretion of N-acetyl-ß-d-glucosaminidase (NAG) activity and ß 2 -microglobulin (ß2MG) . The results showed that high intakes of sunflower kernels (>1 oz/day) significantly increased the intake of cadmium (p<0.004) . However, the amount of cadmium in whole blood or RBCs was not affected by cadmium intake. Urinary excretion of cadmium also was not affected by cadmium intake. Urine NAG activity and the amount of urinary ß2MG were significantly elevated in the urine of high sunflower kernel consumers when the values were expressed on a urine volume basis (p<0.03) , but not when expressed on a creatinine basis (p>0.05) . Because normal ranges for the excretion of these protein markers have not been established, it was not possible to determine if these elevated values were meaningful. However, given the knowledge that habitual consumption of sunflower kernels with natural cadmium concentrations higher than most other food products will increase the average intake of dietary cadmium, the potential exists for an increased body burden of cadmium. Controlled feeding studies in humans should be pursued in order to determine if the body burden does indeed increase and, if so, is it a cause for concern. Key words : cadmium, confectionery sunflower kernels, copper, dietary intake, ferritin, humans, iron, ß 2 -microglobulin, N-acetyl-ß-d-glucosaminidase, zinc. Environ Health Perspect 105:1098-1104 (1997) .
Address correspondence to P.G. Reeves, USDA, ARS Grand Forks Human Nutrition Research Center, 2420 2nd Avenue North, Grand Forks, ND 58203 USA. We acknowledge all volunteers who completed the study and without whose cooperation this study would not have been possible. We also acknowledge the extra financial support from the National Program Staff of the U.S. Department of Agriculture. We thank P. Johnson and R. Chaney for consultation and advice during the study and for reviewing the final manuscript. In addition, we greatly appreciate the able technical assistance of numerous individuals in the Clinical, Dietary, Statistical, and Data Analysis Departments of the Grand Forks Human Nutrition Research Center, with special thanks to E. Nielsen, C. O'Brien-Nimens, S. Gallagher, R. Sims, and M. Siu. Mention of a trademark or proprietary product does not constitute a guarantee or warranty of the product by the U.S. Department of Agriculture and does not imply its approval to the exclusion of other products that may also be suitable. Received 21 March 1997 ; accepted 10 July 1997.
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