Selenium is a trace element. It exists only in rare quantities in the world. It is produced primarily as a by-product of the process of mining copper. It is not recyclable. It is very unevenly distributed in the soils of the earth.
Consequently, the availability of selenium in grasses and grains and, at the next stage of the food chain, in animals, varies considerably from region to region in the world. The human dietary intakes of selenium vary accordingly around the world.
Selenium a vital nutrient for humans
Selenium is a necessary micronutrient that our bodies do not produce. We get our selenium primarily from our diets. Selenium is important for good immune system function, good thyroid function, good reproductive function, and good protection of our cells’ DNA.
Most of the world’s production of selenium occurs in the USA, Canada, and Japan, with lesser amounts coming from China and Australia [Haug]. By far, most of the annual production of selenium is used for industrial purposes. At most, 10 percent of the total annual production is used for soil fertilization; much less than 10 percent is used for nutritional supplements.
Selenium concentrations are known to be too low in the foodstuffs produced in much of Europe, New Zealand, the Middle East, and vast parts of Africa and Asia. In the United States, selenium concentrations in foodstuffs produced in the northeastern and southeastern states and in the northwestern states are considerably lower than the selenium concentrations in foodstuffs produced in the middle of the country [Haug].
To repeat: selenium is an essential nutrient for us humans. We cannot produce selenium themselves. We are totally dependent upon dietary and supplemental intakes of selenium.
We cannot afford to be wasteful with the selenium that we are able to produce from the earth because we are not likely to find ways to improve production or recycling to any significant extent.
Selenium’s valuable biological functions
Prevents deficiency diseases
Randomized controlled trials have shown that supplementation with a selenium enriched yeast preparation reduces the incidence and the effects of deficiency diseases such as Keshan disease (a form of heart disease) and Kashin-Beck disease (a form of bone disease).
Prevents the development of cancer
Randomized controlled trials have shown that daily supplementation with a selenium enriched yeast preparation significantly reduces the risk of cancer incidence and mortality [Blot, Clark, Hercberg, Yu].
Reduces heart disease incidence and mortality
Similarly, a randomized controlled trial has shown that daily supplementation with a selenium enriched preparation and a patented Coenzyme Q10 preparation improves heart function, reduces inflammation and oxidative damage, and improves heart disease mortality rates [Alehagen 2015].
Improves immune function
Selenium deficiency has been associated with impaired immune function, and selenium supplementation has been associated with augmented immune function [Kiremidjian-Schumacher, Roy]. Selenium supplementation has been associated with significant reduction of the risk of immune system decline and death from HIV infections [Baum]. Several studies have shown a close association between selenium intakes and status and autoimmune thyroiditis [Fan].
Official government recognition of selenium’s importance to human health
US Food and Drug Administration
The nutritional importance of selenium is such that the US Food and Drug Administration has permitted the following texts to be placed on the packaging of nutritional supplements containing selenium:
“Selenium may reduce the risk of certain cancers. Some scientific evidence suggests that consumption of selenium may reduce the risk of certain forms of cancer. However, FDA has determined that this evidence is limited and not conclusive.”
“Selenium may produce anti-carcinogenic effects in the body. Some scientific evidence suggests that consumption of selenium may produce anti-carcinogenic effects in the body. However, FDA has determined that this evidence is limited and not conclusive.”
European Food Safety Authority
An investigatory panel of the European Food Safety Authority has concluded that “a cause and effect relationship has been established between the dietary intake of selenium and protection of DNA, proteins, and lipids from oxidative damage, normal immune function, normal thyroid function, and normal spermatogenesis.”
The Government of Finland
Starting in 1985, the government of Finland, until then a country with disastrously low selenium concentrations in the soil, mandated the addition of selenium to agricultural fertilizers. The stated purpose of the selenium addition was to lower the risk of cancer and heart disease caused by selenium deficiency.
Twenty years later, published research showed that the addition of selenium to fertilizers in Finland had raised the selenium intakes of animals and healthy people in Finland to safe and adequate levels.
Fertilization of the soil with the addition of selenium
New Zealand, beginning as early as 1982, and Finland, since 1985, have successfully experimented with the addition of selenium to soil fertilizers. The result has the increase of the selenium content in foodstuffs to levels sufficient for good health in humans [Haug].
However, as Haug points out, yes, okay, the addition of selenium to soil fertilizers is a safe and effective way to increase human consumption of selenium. But, to apply 20 grams of selenium per hectare on one-third of the earth’s arable land would require 1000 tons of selenium each year, approximately 40% of the total annual production of selenium. Then, to apply 20 grams of selenium to one-third of the earth’s pastures would require about 2000 tons of selenium per year [Haug].
Selenium supplementation the only answer for humans
There simply is not enough selenium available to carry out the New Zealand and Finland experiments on a global scale. And, with the world’s population continuing to grow, it is going to be important to conserve and use our stocks of selenium wisely. We should also be thinking about stockpiling selenium for the use of future generations, for our children and their children [Haug].
Nutritional supplementation with selenium is the best way to get the most effect with the smallest amounts of selenium.
Baum, M. K., Campa, A., Lai, S., Sales Martinez, S., Tsalaile, L., Burns, P., & Marlink, R. (2013). Effect of micronutrient supplementation on disease progression in asymptomatic, antiretroviral-naive, HIV-infected adults in Botswana: a randomized clinical trial. Jama, 310(20), 2154-2163.
Blot, W. J., Li, J. Y., Taylor, P. R., Guo, W., Dawsey, S., & Wang, G. Q. (1993). Nutrition intervention trials in Linxian, China: supplementation with specific vitamin/mineral combinations, cancer incidence, and disease-specific mortality in the general population. Journal of The National Cancer Institute, 85(18), 1483-1492.
Clark, L. C., Combs, G. J., Turnbull, B. W., Slate, E. H., Chalker, D. K., Chow, J., & … Taylor, J. R. (1996). 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, 276(24), 1957-1963.
Fan, Y., Xu, S., Zhang, H., Cao, W., Wang, K., Chen, G., & … Liu, C. (2014). Selenium supplementation for autoimmune thyroiditis: a systematic review and meta-analysis. International Journal of Endocrinology, 2014904573.
Haug, A., Graham, R. D., Christophersen, O. A., & Lyons, G. H. (2007). How to use the world’s scarce selenium resources efficiently to increase the selenium concentration in food. Microbial Ecology in Health And Disease, 19(4), 209-228.
Hercberg, S., Galan, P., Preziosi, P., Bertrais, S., Mennen, L., Malvy, D., & Briançon, S. (2004). The SU.VI.MAX Study: a randomized, placebo-controlled trial of the health effects of antioxidant vitamins and minerals. Archives of Internal Medicine, 164(21), 2335-2342.
Kiremidjian-Schumacher, L., Roy, M., Wishe, H.I., Cohen, M.W,
& Stotzky, G. (1996). Supplementation with selenium augments the functions of natural killer and lymphokine-activated killer
cells. Biol Trace Elem Res., 52: 227-39.
Roy, M., Kiremidjian-Schumacher, L., Wishe, H.I., Cohen, M.W., & Stotzky, G. (1992). Effect of selenium on the expression of high affinity interleukin 2 receptors. Proc Soc Exp Biol Med., 200: 36-43.
Yu, S.Y., Zhu, Y.J., & Li, W.G. (1997). Protective role of selenium against hepatitis B virus and primary liver cancer in Qidong. Biol Trace Elem Res., 56: 117-24.
Disclaimer: The information presented in this review article is not intended as medical advice and should not be construed as such.