Selenium from Yeast (SY) shows more protection than selenonethionine (SeMet) in men with prostate cancer
Doggy Bag Message First
The overall evidence suggest’ that selenium ONLY in the form of selenized yeast has potential in being protective against prostate cancer. Selenized Yeast does not cause or promote diabetes and it has no adverse side effects at dosages of up to 800 mcg/day. The RDI upper tolerated dose is 400 mcg/day.
This study and most others use approximately 200mcg/day and that’s what I would recommend. Most men, by the way, consume about 134mcg/day in their diet – but of course that varies.
Details of the study
- The effects of Selenomethionine (SeMet) and Selenized Yeast (SY) were compared for the first time on prostate cancer relevant biomarkers in men.
- A randomized double blind, placebo-controlled trial of SY (200 or 285 mcg/day) and SeMet (200 mcg/day) administered for 9 months in 69 healthy men.
- Researcher looked blood levels of selenium-containing compounds and oxidative stress (free radicals) biomarkers
- (In case you feel geeky today are interested in the biomarkers tested, here they are: urine 8-hydroxy-2′-deoxyguanosine [8-OHdG] and 8-iso-prostaglandin-F2α [8-iso-PGF2α] and blood glutathione [GSH]).
- Secondary endpoint researchers looked for was blood glucose and PSA levels.
- Conclusion: Reduction in biomarkers of oxidative stress following supplementation with SY but not SeMet in healthy men. This study suggests that selenium-containing compounds other than SeMet may account for the decrease in oxidative stress. (Richie et al. 2014)
Other studies on SY and SeMet
Although the Ritche study is the first head-to-head study looking at SY and SeMet, others have independently shown to favor SY over SeMet for its protective qualities.
High-Selenium Yeast, on the other hand, has been found to be more effective than selenomethionine in the reducing DNA damage and an increase in epithelial cell apoptosis (natural cell death) within aging canine prostate cells. (Waters et al. 2003)
In contrast, Dr. David McCormick at the Experimental Toxicology and Carcinogenesis Division, IIT Research Institute in Chicago found no effects with SeMet supplementation on the prevention of prostate cancer in rats (McCormick & Rao. 1999).
A small trial of selenium (SeMet) supplementation among men with a lesion widely regarded as a premalignant precursor of prostate cancer showed no benefit. (Marshall et al. 2011)
A recent report, in the SELECT study showed a significant increase of advanced prostate cancer in men consuming 200mcg/day of SeMet.
Note: The SELECT was a 300 million dollar study looking at vitamin E (in the form alpha-tocopherol) and selenium (in the form of L-selenomethionine) and prevent prostate cancer. The trial was simply called the SELECT trial (SELenium and vitamin E Cancer prevention Trial). More on SELECT HERE.
In the Nutritional Prevention of Cancer (NPC) Study by Clark et al, men receiving supplemental selenium in the form of 200mcg/day of high-selenium yeast (SY), had a reduced incidence of prostate cancer of up to 63% over a period of about 4.5 years.. (Clark et al. 1996)
Lastly, a 2011 meta-analysis of nine randomized controlled clinical trials including 152,538 participants established that selenium supplementation cut risk for all cancers by 24%. The cancer-preventive effect rose to 36% in people with low baseline selenium levels. (Lee et al. 2011)
Selenium also rids the body of unwanted metals – a really good thing.
100 Chinese were randomized to receive 100 micrograms of selenized yeast for 90 days. Urinary excretion of mercury increased by 74% in 30 days and by 175% by 90 days in the Selenium group. (Li YF et al. Enviorn Sci Technol. 2012)
Selenium appears to rid the body of cadmium (a major prostate cancer causing metal), especially in acute exposures. In a mouse study, after acute cadmium exposure a significant decrease in cadmium levels was observed in the kidneys and liver following an eight-week daily selenium supplementation. (Jamba et al. 1997)
My Take On This
The research by Ritchie et al. is exciting. This is the first head-to-head study comparing SeMet to SY. There is a big difference between the two so when claims are made on “Selenium” promoting cancer the question that needs to be asked is; what kind of selenium was used?
Scientists, practitioners and the media who are not trained in nutritional science are guilty of making unspecific, unreliable and potential harmful claims.
In nature, vitamins and minerals work in concert not independently. So when you super concentrate a natural substance as in SeMet the biological effect is often detrimental at high dosages. Besides, super isolation of natural agents would then becomes a drug. And that is what we trying to use less off, right?
Anytime a substance is super concentrated as is the case with pure SeMet, that causes havoc with the interplay that occurs with other essential components of a natural substance. The use of alpha-tocopherol vitamin E alone versus mixed tocopherol vitamin E is another example of this. More on that HERE.
SY, on-the-other-hand consist of 200mcg of THREE types of selenium; selenomethionine selenocysteine and methylselenocysteine of which about 70% is SeMet.
I hope this helps.
Clark LC, et al. Effects of selenium supplementation for cancer prevention in patients with carcinoma of the skin. A randomized controlled trial. Nutritional Prevention of Cancer Study Group. JAMA. 1996;276(24):1957–63.
Jamba L, Nehru B, Bansal MP. Selenium supplementation during cadmium exposure: changes in antioxidant enzymes and the ultrastructure of the kidney. J Trace Elem Exp Med 1997;10:233-242.
Waters DJ, Shen S, Cooley DM, Bostwick DG, Qian J, Combs, Jr. GF, Glickman LT, Oteham C, Schlittler D, and Morris JS. Effects of dietary selenium supplementation on DNA damage and apoptosis in canine prostate. J. Natl Cancer Inst 2003; 95:237-240.