The Durk Pearson & Sandy Shaw®
Life Extension NewsTM
Volume 16 No. 9 • October 2013


Gene Expression Profiling Reveals Some Differences Between Sodium Selenite, Selenomethionine and Yeast-derived Selenium Following Ingestion in the Mouse

Gene expression profiling has become a valuable tool in uncovering mechanisms of action of genes and nutrients that affect their expression. In this new study,1 scientists examined the effects of three forms of selenium used to supplement a base diet at 1 mg/kg diet of added selenium as compared to the base diet deficient in selenium (<0.01 mg/kg diet). The subjects were weanling mice. They received either the base diet without added selenium or the selenium supplemented base diet for 100 days.

The three forms of selenium were reported to be equally effective in activating standard measures of selenium, such as expression of genes encoding selenoproteins. The gene expression profile revealed that sodium selenite and yeast-derived selenium had similar profiles and different from that of selenomethionine. The most interesting/revealing result of the study was that sodium selenite changed the expression of far more genes than the other two forms in the cerebral cortex and gastrocnemius (muscle) and slightly more genes in the intestine than the other two forms.

In the liver, the yeast-derived selenium changed the expression of more genes than the other two forms. For example, in the gastrocnemius, sodium selenite changed the expression of 1082 genes while yeast-derived selenium changed the expression of 637 genes and selenomethionine changed the expression of 148 genes. In the cerebral cortex, the genes changed were 1166, 832, and 421 for selenite, yeast-derived selenium, and selenomethionine. We were quite surprised, wondering why there would be such a large difference in the number of expressed genes (particularly in muscle). Moreover, the DNA damage response gene Gadd45b had a lowered expression in response to yeast-derived selenium in all tissues, while sodium selenite reduced its expression in cortex and gastrocnemius, and selenomethionine reduced its expression only in cortex. The authors also point out that the overlap of changes in gene expression that were changed in the same direction was greater for sodium selenite and yeast-derived selenium than any other pair of treatments. There is a complete list of the individual genes changed in expression by more than one diet for all four tissues in Online Resources 1–4, which we have not reported here.

The authors point out that the results of this study clearly show that research based upon different forms of selenium cannot be considered equivalent and that “the published data regarding the effect of selenium should be re-evaluated with respect to the source of selenium that was administered.”1

Note that the most common form of natural dietary selenium is sodium selenite. Importantly, the prostate cancer killing effect of selenium was strongest for sodium selenite as reported in a recent paper.2

References

  1. Barger et al. Gene expression profiling reveals differential effects of sodium selenite, selenomethionine, and yeast-derived selenium in the mouse. Genes Nutr. 7:155-165 (2012).
  2. Olm et al. Extracellular thiol-assisted selenium uptake dependent on the xc- cystine transporter explains the cancer-specific cytotoxicity of selenite. Proc Natl Acad Sci USA. 106(27):11400-5 (2009).

Featured Product

  • Learn more about Selenium benefits and implementation strategies.

Ingredients in this Article

FREE Subscription

  • You're just getting started! We have published thousands of scientific health articles. Stay updated and maintain your health.

    It's free to your e-mail inbox and you can unsubscribe at any time.
    Loading Indicator