Selenium (Se) is a trace mineral that can be found in foods and supplements. It is available in both organic and inorganic forms and is an essential nutrient for humans and animals. In the body, selenium works as an antioxidant, protecting cells from free radical damage. It has an important role in thyroid hormone synthesis, the male reproductive system, and other bodily processes.[3, 4]
How Is Selenium Found in Our Diet?
The amount of selenium in plants is directly linked to the concentration of the element in the soil. Plants absorb inorganic selenium from the earth and convert it into organic forms. Environmental factors affect the amount of selenium a plant absorbs. The pH of the soil, temperature, air humidity, and ground moisture all affect selenium uptake. Because of these variations, selenium concentration in plant-based foods varies region to region. Selenium levels can change over such a small area that the vegetables in your neighbor’s garden may have more selenium than yours.
Selenium content in meat can also vary, although not as drastically. The selenium content of animal products depends on the concentration of the element in the plants they eat. What does this variation mean for our daily selenium requirements?
When you look at a nutrition label you’ll see the Recommended Dietary Allowance (RDA). The RDA is defined as the “average daily level of intake sufficient to meet the nutrient requirements of nearly all (97%–98%) healthy people.” Notice the definition says “sufficient” and not “optimal.” Every person’s needs differ. A breastfeeding woman needs much more selenium than a nine-year-old boy, for example. Your optimal selenium requirements may be higher or lower than what the label says. The following chart provides a more complete perspective about daily selenium requirements.
|Life Stage||Selenium Requirement (in micrograms)|
|Birth – 6 months||15 mcg|
|7-12 months||20 mcg|
|1-3 years||20 mcg|
|4 – 8 years||30 mcg|
|9 – 13 years||40 mcg|
|14 – 18 years||55 mcg|
|19 – 50 years||55 mcg|
|51+ years||55 mcg|
If you find yourself in need of more selenium in your diet, you can try a supplement. You can find selenium in multivitamins or by itself. Whatever supplement you try, be sure to read the label.
4 Types of Selenium Supplements
When choosing a selenium supplement, pay attention to the form of selenium it contains. Selenium is available in several forms, and not all of them offer the same health benefits. Different forms are absorbed and metabolized differently. The most important distinction between the various selenium forms is whether it’s organic or inorganic. Inorganic forms of selenium are easily absorbed through the intestine but poorly retained. Once they reach the blood, inorganic selenium is quickly filtered out by the kidneys and excreted in urine. Suffice to say, that won’t provide the full nutritional benefits of the nutrient.
Conversely, organic, protein-bound selenium is better retained, utilized, and incorporated by the human body. Organic selenium supplements are often extracted from food sources. Selenium-containing amino acids, such as selenomethionine, are introduced directly into proteins, including the proteins that make up our muscles. About 90% of the selenomethionine we take in is actually absorbed in the intestinal tract, and about half of that stays in the body.
The most common types of selenium found in supplements are:
- Selenium sulfide – A topical substance that is generally not considered a supplement. Selenium sulfide is an anti-infective agent that relieves itching and flaking of the scalp. It’s often used in lotions and shampoos.
- Sodium Selenite – An inorganic form of selenium usually derived from a synthetic process.
- Selenium-enriched yeast – An organic form of selenium produced from yeast fermentation.
- Selenomethionine and Selenocysteine – Naturally occurring organic amino acids that contain selenium.
Why Do We Need Selenium Supplementation?
Regional differences in selenium concentration in soil make it difficult to accurately estimate your daily selenium intake. Consuming an unsuitable amount of selenium can contribute to health problems. A multitude of factors can cause some sort of selenium deficiency. Kidney dialysis, HIV infection, smoking, and heavy alcohol consumption can all severely lower selenium levels in the body.[13,14,15,16] Talk to your healthcare practitioner if you’re worried that you suffer from selenium deficiency. They can test selenium levels by analyzing blood, urine, hair, and nails.
How to Choose the Best Selenium Supplement?
I personally recommend whole food, plant-based supplements over those created synthetically. In addition, plant-based supplements, particularly mustard seed-derived selenium, contain the best form of this trace mineral. It also is one of the most difficult forms to get too much of, making it a safer choice to take regularly.
We formulated a chemically organic (carbon-bound) selenium supplement. It’s extracted from mustard seeds and I’m extremely proud of it. The selenium complex in our supplement is minimally processed to protect the delicate carbon-bound selenium found in mustard.
Have you added selenium to your life? What changes have you noticed? Let us know in the content section.
- “Dietary Supplement Fact Sheet: Selenium.” National Institutes of Health. U.S. Department of Health & Human Services, 11 Feb. 2016. Web. 28 Mar. 2016.
- Haug, Anna et al. “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 (2007): 209–228. PMC. Web. 28 Mar. 2016.
- Ahsan, U., Z. Kamran, I. Raza, S. Ahmad, W. Babar, M.h. Riaz, and Z. Iqbal. “Role of Selenium in Male Reproduction—A Review.” Animal Reproduction Science 146.1-2 (2014): 55-62. Web.
- Tinggi, Ujang. “Selenium: Its Role as Antioxidant in Human Health.” Environmental Health and Preventive Medicine 13.2 (2008): 102–108. PMC. Web. 28 Mar. 2016.
- Agriculture, Board On, Subcommittee On Selenium, National Research Council, and Committee On Animal Nutrition. “3: Distribution.” Selenium in Nutrition, Revised Edition. N.p.: National Academies, 1983. N. pag. Print.
- Tapiero, H., D.m Townsend, and K.d Tew. “The Antioxidant Role of Selenium and Seleno-compounds.”Biomedicine & Pharmacotherapy 57.3-4 (2003): 134-44. Web. 28 Mar. 2016.
- Temmerman, Ludwig De, Nadia Waegeneers, Céline Thiry, Gijs Du Laing, Filip Tack, and Ann Ruttens. “Selenium Content of Belgian Cultivated Soils and Its Uptake by Field Crops and Vegetables.” Science of The Total Environment 468-469 (2014): 77-82. Web. 28 Mar. 2016.
- “Selenium in Counties of the Conterminous States.” U.S. Geological Survey. USA.gov, n.d. Web. 28 Mar. 2016.
- Fairweather-Tait, Susan J, et al. “Selenium Bioavailability: Current Knowledge and Future Research Requirements.” The American Journal of Clinical Nutrition, vol. 91, no. 5, May 2010, pp. 1484–1491. Accessed 21 Sept. 2016.
- “Selenium Sulfide: MedlinePlus Drug Information.” MedlinePlus, U.S. National Library of Medicine, 16 Sept. 2016. Accessed 21 Sept. 2016.
- “Sodium Selenite.” PubChem, U.S. National Library of Medicine, 2005. Accessed 21 Sept. 2016.
- Combs, Gerald F. “Selenium in Global Food Systems.” BJN British Journal of Nutrition 85.05 (2001): 517. Web. 28 Mar. 2016.
- Swanson, CA, and Et Al. “Selenium Intake, Age, Gender, and Smoking in Relation to Indices of Selenium Status of Adults Residing in a Seleniferous Area.” American Journal of Clinical Nutrition 52.5 (1990): 858-62. Print.
- Hartman, Terryl J. “Toenail Selenium Concentration and Lung Cancer in Male Smokers (Finland).”Cancer Causes & Control 13.10 (2002): 923-28.JSTOR. Web. 28 Mar. 2016.
- Bjørneboe, GA, J. Johnsen, A. Bjørneboe, J. Mørland, and CA Drevon. “Effect of Heavy Alcohol Consumption on Serum Concentrations of Fat-soluble Vitamins and Selenium.” Alcohol Suppl. 1 (1987): 533-37. Web. 28 Mar. 2016.
- Suhajda, Á., J. Hegóczki, B. Janzsó, I. Pais, and G. Vereczkey. “Preparation of Selenium Yeasts I. Preparation of Selenium-enriched Saccharomyces Cerevisiae.” Journal of Trace Elements in Medicine and Biology 14.1 (2000): 43-47. Web. 28 Mar. 2016.
- Bañuelos, Gary S., et al. “Quantification, Localization, and Speciation of Selenium in Seeds of Canola and Two Mustard Species Compared to Seed-Meals Produced by Hydraulic Press.” Analytical Chemistry, vol. 84, no. 14, 2012. Accessed 21 Sept. 2016.