Excretion and Retention of Stable Strontium in Children

Abstract

THE turnover of stable strontium, a minor mineral constituent of the diet, chemically similar to calcium, has been studied in man in order to compare the metabolic behaviour of strontium and calcium and to estimate the accumulation of fall-out strontium-90 in the body, ingested at a constant rate over a long period. So far, little information has been obtained from studies of children because the experiments have involved giving doses of the radioactive isotope. Measurements of the residence time of strontium in children aged less than one year have been obtained, however, by comparing the amounts of natural strontium ingested and excreted^1,2, but for the study of older children this method is unreliable because the accumulated strontium approaches a state of equilibrium attained in adult life. In previous work in this laboratory, the accumulation of strontium and calcium in four children aged 4–14 yr was studied by giving doses of 100 mg of natural strontium³, but because the normal dietary intake at these ages is only 1 mg a day, these large doses may have disturbed the balance of strontium in the body and invalidated the conclusions of the experiments. In the work reported here, we have overcome this problem—and at the same time avoided giving doses of radioactive isotopes to children—by using stable strontium enriched in ⁸⁴Sr (Oak Ridge Laboratories). The information on strontium turnover could thus be obtained whilst the subjects consumed a normal diet with a normal content of natural strontium.