In a new scientific study Danish researchers from Copenhagen University have demonstrated that methylated selenium compounds can regulate the body's immune system enabling it to better fight certain cancers. These selenium compounds are found in certain foods such as garlic and broccoli, but also in selenium yeast.
Certain cancers such as skin cancer, prostate cancer and some leukemias weakens the body's immune system by overstimulating it until it eventually breaks down, giving cancer cells a free rein in the body. What this research shows is that intake of selenium compounds that can be metabolized into methylselenol improves the immune system's ability to fight cancer.
The immune activating substance NKG2D
The metabolism of various inorganic and organic-selenium compounds in the body is complex and closely regulated. The selenium compound methylselenol regulates the production of a substance called NKG2D. It is a substance which activates the body's immune function and is seen in large amounts, in for example, heat shock, viral infections and inflammation, but also in the blood and on the surface of tumors in cancer patients. This substance is therefore also used as a marker for serious illness. The selenium compounds which are converted to selenide in the body, are not in a position to regulate the formation of NKG2D and are therefore less effective as anti-cancer agents.
This is where the selenium yeast enters the picture, because it contains the methylated selenium compounds that have been found most effective in cancer treatment.
Selenium fights cancer primarily using two pathways: apoptosis and anti-angiogenesis. By apoptosis enzymes are affected that causes cancer cells to die. It is also called programmed cell death. The other pathway, anti-angiogenesis is a process that inhibits the formation of new blood vessels to the cancer tumor. Without supply of adequate nutrients through new blood vessels, the cancer cells will die.
In fact the effects of selenium on cancer are enhanced with conventional chemotherapy.
Other scientific studies involving selenium have shown that a daily supplement of 200 micrograms of selenium yeast has been able to reduce the number of cancer incidents and also deaths due to cancer, but the above research suggests that the type of selenium used against cancer greatly affect the results. It is noteworthy that the SELECT study from 2008, where selenomethionine (which is a non-methylated selenium) was used for cancer patients, did not show a statistically significant effect against cancer. This negative result that has surprised many, has been attributed to several things, including that the patients were not lacking selenium, but according to this new Danish research the results could also be the explained by the fact that they were not using methylated selenium compounds.
Another thing that is pointed out by the researchers is that you can't get the necessary amounts of selenium that fights cancer from the diet alone.
Hagemann-Jensen M, et al. The Selenium Metabolite Methylselenol Regulates the Expression of Ligands That Trigger Immune Activation through the Lymphocyte Receptor NKG2D. J Biol Chem. 2014;289(45):31576-90.
Weekley CM, et al. Uptake, distribution, and speciation of selenoamino acids by human cancer cells: X-ray absorption and fluorescence methods. Biochemistry. 2011;50(10):1641-50.