Selenium intake and urinary excretion in persons living near a high selenium area.

Selenium intake by adults consuming self-selected levels of four different diets averaged 209 micrograms. per day and correlated well with caloric and protein intake. Urinary selenium concentration averaged 0.108 microgram. per milliliter, and 24-hour excretion for the various diets averaged 58.0% to 88.6% of the intake. The data suggest that the RDA upper limit of 200 micrograms. of selenium per day and the suggested maximum urine selenium concentration may be too restrictive. The data further indicate that even though there are differences in the absorption of selenium from different sources, the average is about 70% for foods purchased in the Northern Great Plains area.