The Selenium-Cancer Link that Can No Longer Be Ignored




While micronutrients are extremely important for the overall health, most people aren`t getting enough. Mark Whitacre, Ph.D., is a leading expert on selenium, one of the most important micronutrients.

Selenium was discovered 200years ago by the Swedish chemist, Baron Jöns Jacob Berzelius.  These days, it is recognized as an essential mineral with powerful anti-cancer, antiviral, and anti-inflammatory properties.

“After I finished my master’s degree at Ohio State, I went to Cornell University to get my Ph.D. in nutritional biochemistry and to study under Gerald F. Combs Jr.[,Ph.D., who] was probably the leading authority in selenium research, and probably still is,” Whitacre says.

During his research on the topic, Whitacre explored the biochemical role of selenium in pancreatic cells.

Selenium in Health and Disease Prevention

Selenium has two very important roles:
  • At cellular level, selenium is an active compound of glutathione peroxidase, an enzyme with very powerful antioxidant properties and an ability to protect against build-up of detrimental free radicals in the cells.
  • Selenium plays an important role in cancer prevention, working by reducing free radicals which are one of the major causes of cancer.

Excessive Iron + Selenium Deficiency = Bad News



Iron is known to react with hydrogen peroxide to form free radicals.  These free radicals can damage the proteins, cell membranes, and mitochondrial DNA and lead to premature death of the mitochondria.

It is recommended to get iron levels tested once annually and to maintain a level between 20 and 80 nanograms per milliliter (ng/mL), and ideally between 40 and 60 ng/mL.

Although low iron can be a huge problem, it is treated with iron supplementation.  In fact, most people have too much iron, particularly children and premenopausal women.

Due to that excess iron, hydroxyl free radicals are catalyzed and the situation is worsened if the person is selenium deficient.

Check Your Iron Levels Annually

As noted by Whitacre:

“Excessive iron does create some challenges. Actually, my Ph.D. thesis, looking at the biochemical role of selenium in the pancreatic cell … [showed that] chicks with selenium deficiency get pancreatic fibrosis …

Basically, once [the chicks were] 21 to 28 days [old], when they were selenium deficient on a purified diet, they wouldn’t survive at all … Most of that damage we saw early on — the earliest damage we can detect — was mitochondrial membrane [damage].

We could see the degeneration of that mitochondrial membrane … basically, the peroxide oxidizing and attacking those lipids … [The mitochondrial membrane] is really one of the areas that’s impacted first … because of the generation of free radicals inside the mitochondria.”

The Selenium-Cancer Connection

The first study on the topic was done by Combs, Whitacre’s thesis adviser at Cornell University. The late Larry C. Clark, Ph.D., and former director of the Arizona Cancer Center’s epidemiology program at the University of Arizona, was another Cornell researcher.

“In 1983, which was my last year at Cornell, [Combs and Clark] started a 10-year study looking at 200 micrograms (mcg) per day of selenium supplementation using high selenium yeast compared to no supplementation …

They found … there was a 50 to 63 percent reduction in cancer rates in colon, lung and prostate, with the highest number of 63 percent rate reduction in prostate cancer …

That was probably the first study that really looked at the impact of selenium supplementation on cancer reduction. Since that point, there’s been dozens of studies verifying that work,” Whitacre says.

“That work really emphasized … the thought that the glutathione peroxidase reducing free radical production was the biological role. There is some newer work that looks like there may possibly be another function … beyond the antioxidant role of glutathione peroxidase …

Most of the works since [then] has really been looking more at selenium form. That study used SelenoExcell high-selenium yeast, and there’s been several studies that have looked at sodium selenite [and] selenomethionine, and have not seen the same effect …  [F]orm does make a difference.

The SelenoExcell high-selenium yeast has been the most effective form. Matter of fact, selenomethionine had no effect in a very long term cancer research study published in 2011 called the SELECT trial …”

Best Food Sources of Selenium

Generally speaking, eating whole, unprocessed foods will naturally boost your selenium levels. Good food sources of selenium include sardines, Chia seeds, mushrooms, liver,  organic eggs,  brazil nuts, sunflower seeds, chicken, turkey, and salmon .