Mark Whitacre Research Review: Selenium and Maternity; Form Matters

Superiority of organic vs inorganic selenium. When discussing the role of selenium before, during and after pregnancy, it is important to point out that not all selenium is the same. (Rayman, 2004).  More recently, organic bound selenium, such as that found in high-selenium yeast (SelenoExcell®) was found to protect DNA from lead damage in vitro, while an inorganic form (sodium selenite) actually promoted lead-induced DNA damage (McKelvey et al, 2015). 


Not surprisingly then, the most effective clinical trials investigating the role of selenium supplementation on reducing pregnancy and birth complications have utilized high-selenium yeast providing 100 μg selenium daily with the following benefits;

  • 60% reduced risk of having a preterm birth due to premature rupturing of membranes (ie, ‘water breaking’) (Tara et al, 2010)
  • 60-70% reduced risk of developing pre-eclampsia (Vanderlelie & Perkins, 2011)
  • 65% reduced risk of experiencing intrauterine growth restriction (IUGR) in those who were at an increased risk for this significant problem (Mesdaghinia et al, 2017)

Other benefits of high-selenium yeast supplementation during pregnancy from the above trials include:

  • Reduced risk for elevated blood glucose (which is associated with preterm births)
  • Reduced oxidative damage and inflammation (also associated with preterm births)
  • Improving insulin sensitivity
  • Increasing plasma glutathione levels (which as a side-note is also reduced in autistic children)

In addition, women given 100 μg selenium daily from high-selenium yeast during lactation had much higher selenium content in their breast milk than those given the same amount of selenium but from selenite (Kumpulainen et al, 1985).

Superiority of SelenoExcell® vs selenomethionine

High-selenium yeast also appears to be superior to selenomethionine even though the latter comprises approximately 54-74% of the selenium found in high-selenium yeast.  The basis for this superiority is both direct and indirect.  In a recent and direct head-to-head comparison between selenomethionine and high-selenium yeast supplementation for 9 months, SelenoExcell® was shown to be superior to selenomethionine in terms of significantly reducing oxidation (i.e., 60% ↓ 8-isoprostanes), as well as significantly reducing DNA damage (i.e., 30% ↓ 8-OHdG), while selenomethionine did not decrease such levels at all (Richie Jr et al, 2014 ).  Indirect superiority is derived from similar trials utilizing the two different forms of selenium with two differing outcomes.  In the trial involving SelenoExcell® supplementation (200μg selenium/d), cancer mortality was reduced 50%, while the prevalence of prostate, colorectal and lung cancers were reduced 63%, 58% and 46%, respectively, compared to placebo (Clark et al, 1996); being most effective in those with the lowest plasma selenium levels where SelenoExcell® supplementation reduced the incidence of prostate cancer 92% (Clark et al, 1998).  Selenomethionine supplementation not only did not provide such benefits in a similar clinical trial (known as the SELECT trail), but the study was halted early due to non-significant 9% increase in the incidence of prostate cancer (Lippman et al, 2009).  To be fair, individuals in the SELECT trial did have higher baseline blood selenium levels than those in the Nutrition Prevention of Cancer Study that utlized SelenoExcell®.


  • Clark LC, Combs Jr GF, Turnbull BW et al.  Effects of selenium supplementation for cancer prevention in patients with carcinoma of the skin.  J Am Med Assoc  1996;276:1957-63. 
  • Clark LC, Dalkin B, Krongrad A et al.  Decreaed incidence of prostate cancer with selenium supplementation: results of a double-blind cancer prevention trial.  Br J Urology  1998;81:730-4.
  • Kumpulainen J, Salmenpera L, Siimes MA et al.  Selenium status of exclusively breast-fed infants as influenced by maternal organic or inorganic selenium supplementation.  Am J Clin Nutr  1985;42:829-35.
  • Lippman SM, Klein EA, Goodman PJ et al.  Effect of selenium and vitamin E on risk of prostate cancer and other cancers.  JAMA  2009;301-39-51.
  • McKelvey SM, Horgan KA, Murphy RA.  Chemical form of selenium differentially influences DNA repair pathways following exposure to lead nitrate.  J Trace Elem Med Biol  2015;29:151-69.
  • Mesdaghinia E, Rahavi A, Bahmani F et al.  Clinical and metabolic response to selenium supplementation in pregnant women at risk for intrauterine growth restriction: randomized, double-blind, placebo-controlled trial.  Biol Trace Elemn Res  2017;178:14-21.
  • Rayman MP.  The use of high-selenium yeast to raise selenium status: how does it measure up?  Br J Nutr  2004;92:557-73.
  • Richie Jr JP, Das A, Calcagnotto AM et al. Comparative effects of two different forms of selenium on oxidative stress biomarkers in healthy men: a randomized clinical trialCancer Prev. Res  2014;7:796–804.
  • Tara F, Rayman MP, Boskabadi H et al.  Selenium supplementation and premature (pre-labour) rupture of membranes: a randomized double-blind placebo-controlled trialJ Obstet Gynaecol  2010;30:30-4.
  • Vanderlelie JJ, Perkins AV.  Selenium and preeclampsia: a global perspectivePregnancy Hypertens  2011;1:213–24.


Cypress-Dr-Mark-WhitcareAuthor Dr. Mark Whitacre is the Chief Science Officer at Cypress Systems. Dr. Whitacre has nearly two decades of executive management experience in both Fortune 500 and entrepreneurial companies, including broad international experience. Much of his career has been in the area of biotechnology and microbiol fermentation. Dr. Whitacre earned a Ph.D. in Nutritional Biochemistry from Cornell University where he studied under a world-renowned selenium scientist, Dr. G.F. Combs, Jr.  



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