CADMIUM BIOAVAILABILITY FROM EDIBLE SUNFLOWER KERNELS: A LONG-TERM STUDY WITH MEN AND WOMEN VOLUNTEERS

Authors: Reeves, Phillip; Nielsen, Emily; O'BRIEN-NIMENS, CYNDY - UNIV OF NORTH DAKOTA; VANDERPOOL, RICHARD - 5450-10-00

Submitted to: Environmental Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/20/2001
Publication Date: 10/1/2001
Citation: Reeves, P.G., Nielsen, E.J., O'Brien-Nimens, C., Vanderpool, R.A. 2001. Cadmium bioavailability from edible sunflower kernels: a long-term study with men and women volunteers. Environmental Research. 87:81-91.

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 sunflower seeds over a long period of time, will they begin to show that they have too much cadmium in their bodies? We asked people to eat a prescribed amount of sunflower kernels as a part of their regular diet for almost one year. Then we measured the content of cadmium in their blood and urine as indicators of cadmium in the body. We also looked for small proteins that come out in the urine as a result of altered kidney function. We found that people who ate 9 ounces of kernels/week had no more cadmium in their urine or blood than those who ate no kernels. The amount of small proteins excreted in the urine were not different whether the person ate sunflower kernels or not. These findings address the critical issues surrounding recommendations for safe and adequate intakes of cadmium. They strongly suggest that people who eat a higher than the average amount of sunflower kernels per week are no more likely to have too much cadmium in their bodies than those who do not eat the kernels.

Technical Abstract: Most foods consumed in the United States contain low amounts of cadmium (Cd), but some contain higher amounts. Thus, individuals who consume large amounts of a high-Cd food, may be at risk of Cd toxicity, but only if the Cd is available for absorption. Confectionery sunflower kernels (CSFK) contain natural Cd in somewhat higher amounts than in most other foods. This study was designed to determine if a change in the body burden of Cd could be detected in volunteers who consumed a controlled amount of CSFK for 48 wk. Healthy men and women volunteers between 23 and 59 years of age were divided into 3 groups each by age, sex, and weight. Over the 48 wk period, one group consumed 255 g (9 oz.) of CSFK/wk, a second group consumed 113 g CSFK/wk and 142 g peanuts, and a third group consumed 255 g peanuts/wk. CSFK contained 0.52 mg Cd/kg, which increased the average estimated intake of Cd from 65 to 175 ug/wk. Peanuts contained 0.11 mg Cd/kg. At the beginning and at quarterly intervals during the study, various parameters were measured to assess the amount of Cd entering the body. Although the estimated Cd intake increased significantly as a result of consuming the Cd-containing CSFK, there were no significant changes in Cd concentration in red blood cells or Cd excretion in the urine as a result of consuming the CSFK. However, fecal Cd excretion increased as the amount of CSFK consumption increased. Hair Cd was not significantly affected by the consumption of CSFK. N-acetyl-beta-glucosaminidase (NAG), a marker for kidney dysfunction was not changed by consuming CSFK. Overall, the results suggest that the consumption of Cd in the form of CSFK at a rate approximately 2 1/2 times the normal intake 48 wk had no adverse effect on the body burden of Cd.