Long-term supplementation with selenate and selenomethionine: Urinary excretion by New Zealand women

Marion F. Robinson, Christine D. Thomson, Christopher P. Jenkinson, Gu Luzhen, Philip D. Whanger

Research output: Contribution to journalArticle

26 Scopus citations

Abstract

Thirty-six New Zealand women aged between 18 and 23 years received daily for 32 weeks, 200 μg Se as Se-enriched yeast (selenomethionine, SeMet), or brewer's yeast mixed with selenate, or no added Se (placebo) in a double-blind trial. Mean daily Se excretion increased with both supplements; the selenate group excreted more than the SeMet group, 123 v. 66 μg/d respectively at week 2, equivalent to 57 v. 27% of the dose. Thereafter Se output increased for the SeMet group reaching a plateau at about 100 μg/d at week 16, when plasma Se had also plateaued at 190 ng/ml. The selenate group had reached an earlier plateau of 110 ng Se/ml at week 7. There was a close relationship between 24 h urine and plasma Se for the SeMet group but not for the selenate group. Renal plasma clearances showed two distinctly different responses; the clearance of 0.4 ml/min reached by the SeMet group at week 2 plateaued as plasma Se increased almost 2-fold; whereas for the selenate group the clearance varied between 0.8 and 1.1 ml/min whilst plasma Se remained almost constant at 110 ng/ml. Previous studies, also of 200 μgSe/d as Se-rich bread, in New Zealand (NZ) and elsewhere showed similar responses to Se-yeast; the selenite response was intermediate between selenate and Se-yeast (SeMet). The full significance of these studies awaits identification of Se components in plasma, glomerular filtrate and urine; meanwhile renal clearances serve as a pointer to changes in the distribution of Se-containing fractions in the plasma. Trimethylselenonium was detected in basal urines, and was a minor component in urines of supplemented NZ subjects at about 1% of the total Se.

Original languageEnglish (US)
Pages (from-to)551-563
Number of pages13
JournalBritish Journal of Nutrition
Volume77
Issue number4
DOIs
StatePublished - Apr 1 1997

Keywords

  • Renal plasma clearance
  • Selenium
  • Urinary excretion
  • Women

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Nutrition and Dietetics

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