SELENATE AND SELENITE ABSORPTION AND RETENTION IN INFANTS

Abstract

41 Very little information is available on selenium (Se) absorption and retention of different Se compounds in infants. The aim of this study was to determine the absorption and retention of selenate and selenite added to an infant formula in infants, using stable isotope methodology. Two batches of labelled milk-based infant formula (500g each per infant, ready-to-feed) were prepared by addition of 10 µg Se as 76Se-selenate or as 74Se-selenite. Nine infants were fed the two batches of formula as alternate feeds until completely consumed. Complete collections of feces and urine were carried out during 72 hours. The infants' plasma and erythrocyte Se levels were 66.3 ± 13.3 µg Se/L and 0.392 ± 0.135 µg Se/g Hb respectively (mean ± SD). These levels were comparable to those observed in North American infants, but higher than those in European infants. Se absorption was significantly higher for selenate (97.3 ± 1.3%) than for selenite (73.4 ± 5.6%). Urinary excretion represented 37.1 ± 4.5% and 9.2 ± 1.8% of the administered dose for selenate and selenite, respectively. Consequently, Se retention was similar for the two inorganic Se compounds (60.6 ± 4.9% for selenate; 64.4 ± 5.0% for selenite). No significant correlations were observed between Se status markers and Se absorption and retention data. In conclusion, this study demonstrated that both inorganic Se compounds are equally well retained in infants. Therefore the impact of Se fortification of infant formulas on the Se nutritional status of infants is expected to be similar for selenate and selenite.