Simultaneous determination of absorption of selenium from poultry meat and selenite in young men: application of a triple stable-isotope method.

A triple stable-isotope method was used to estimate simultaneously selenium absorption from poultry meat intrinsically labelled with 74Se and from an extrinsic tracer of 76SeO3(2-) in four young adult men. The subjects received an experimental diet based on chicken meat as the source of protein. Two diet periods, lasting from 5 to 10 d, depending on the frequency of stool output for each subject, were conducted to allow duplicate determinations within each subject of Se absorption from both sources. Absorption of Se was determined by the faecal isotope balance procedure through monitoring the stable isotopes 74Se, 76Se and 80Se by means of radiochemical neutron activation analysis. For the separate periods, mean (with SEM) absorption of 74Se from the intrinsically-labelled poultry meat was 70.9 (1.5)% and 72.0 (2.5)%. The absorption of Se from 76SeO3(2-) was 34.7 (5.5)% and 37.6 (3.2)% during the same periods. From these results it is concluded that, under the present experimental conditions, the intrinsic and extrinsic Se isotopes did not form a common pool before absorption. Possible reasons for this are discussed.