Author
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Reeves, Phillip |
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Vanderpool, Richard |
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Submitted to: Environmental Health Perspectives
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 7/10/1997 Publication Date: N/A Citation: N/A Interpretive Summary: Cadmium is a trace element found in small amounts in most foods. Instead of being a nutrient, it is most often thought of as a toxin. If humans eat too much of it over a long period of time, they might develop problems with kidney function. Most soils contain a small amount of cadmium. Some plants grown in these soils tend to take up cadmium and deposit it in their seeds. The sunflower is one of the plants that will do this. As a result, the seeds contain more cadmium than is found in most other grains. If humans eat a lot of the seeds over a long period of time, will they begin to show that they have too much cadmium in their bodies? We surveyed people to determine their usual intakes of sunflower kernels. Then we measured the content of cadmium in their blood and urine. We also looked for small proteins that come out in the urine as a result of altered kidney function. We found that people who reported eating more than one ounce of kernels/week had no more cadmium in their urine or bloo than those who reported eating less than one ounce/wk, or none at all. The small proteins, however, were present higher in the urine of people who ate >1 ounce of kernels than people who did not eat kernels. But, the highest values for this protein were not higher than the normal range reported for normal people by other investigators. This study strongly suggests that people who eat a higher than the average amount of sunflower kernels are no more likely to have too much cadmium in their bodies than those who do not eat the kernels. Technical 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 U.S.A. is higher than in most other grains. We tested the hypothesis that the high consumption of sunflower kernels will increase the body burden of cadmium and impair the health of humans. Sixty-six men and women who reported consuming various amounts of sunflower kernels were recruited and divided by gender and kernel consumption; those who consumed less than or equal to 1 oz/wk and those who consumed more than 1 oz/wk. Cadmium intake was assessed by calculation from 7-day food diaries, cadmium burden by whole blood, red cell (RBC) and urine cadmium concentrations, and health effects by urinary excretion of N-acetyl-BETA-D-glucosaminidase (NAG) activity and BETA2-microglobulin (BETA2MG). Results showed that high intakes of sunflower kernels (>1 oz/d) significantly increased the intake of cadmium (P<0.004). However, cadmium in whole blood or RBC was unaffected by cadmium intake (P>0.1). Urinary cadmium also was unaffected by cadmium intake. Urinary NAG and BETA2MG were significantly elevated (P<0.03) of high sunflower kernel consumers when the values were expressed on a urine volume basis, but not when expressed on a creatinine basis (>0.05). Because normal ranges for these protein markers have not been established, it was impossible to determine if these elevated values were meaningful. However, because sunflower kernels contain higher amounts of cadmium than most other grains, consuming a lot of them might increase the body burden of cadmium. Further studies should be carried out. |
